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authorDavid Baker <dave@matrix.org>2014-12-18 15:15:22 +0000
committerDavid Baker <dave@matrix.org>2014-12-18 15:15:22 +0000
commitb56730bb6e549e6b22c95858cae50e091de96844 (patch)
tree0eb011bc6b32a44df8c343ffedbc15e2ddd046e9 /synapse
parentschema version is now 10 (diff)
parentUpdate README.rst (diff)
downloadsynapse-b56730bb6e549e6b22c95858cae50e091de96844.tar.xz
Merge branch 'develop' into pushers
Conflicts:
	synapse/api/errors.py
	synapse/server.py
	synapse/storage/__init__.py
Diffstat (limited to '')
-rw-r--r--synapse/__init__.py2
-rw-r--r--synapse/api/auth.py106
-rw-r--r--synapse/api/constants.py15
-rw-r--r--synapse/api/errors.py3
-rw-r--r--synapse/api/events/__init__.py148
-rw-r--r--synapse/api/events/factory.py90
-rw-r--r--synapse/api/events/room.py170
-rw-r--r--synapse/api/events/validator.py87
-rw-r--r--synapse/api/urls.py1
-rwxr-xr-xsynapse/app/homeserver.py22
-rw-r--r--synapse/config/_base.py14
-rw-r--r--synapse/config/logger.py2
-rw-r--r--synapse/config/repository.py9
-rw-r--r--synapse/crypto/event_signing.py44
-rw-r--r--synapse/events/__init__.py149
-rw-r--r--synapse/events/builder.py77
-rw-r--r--synapse/events/snapshot.py (renamed from tests/events/__init__.py)7
-rw-r--r--synapse/events/utils.py (renamed from synapse/api/events/utils.py)69
-rw-r--r--synapse/events/validator.py92
-rw-r--r--synapse/federation/replication.py137
-rw-r--r--synapse/federation/transport.py2
-rw-r--r--synapse/handlers/_base.py106
-rw-r--r--synapse/handlers/directory.py31
-rw-r--r--synapse/handlers/federation.py265
-rw-r--r--synapse/handlers/message.py93
-rw-r--r--synapse/handlers/presence.py50
-rw-r--r--synapse/handlers/profile.py35
-rw-r--r--synapse/handlers/register.py6
-rw-r--r--synapse/handlers/room.py218
-rw-r--r--synapse/handlers/typing.py129
-rw-r--r--synapse/http/matrixfederationclient.py123
-rw-r--r--synapse/http/server.py29
-rw-r--r--synapse/media/__init__.py0
-rw-r--r--synapse/media/v0/__init__.py0
-rw-r--r--synapse/media/v0/content_repository.py (renamed from synapse/http/content_repository.py)2
-rw-r--r--synapse/media/v1/__init__.py0
-rw-r--r--synapse/media/v1/base_resource.py369
-rw-r--r--synapse/media/v1/download_resource.py68
-rw-r--r--synapse/media/v1/filepath.py67
-rw-r--r--synapse/media/v1/media_repository.py77
-rw-r--r--synapse/media/v1/thumbnail_resource.py182
-rw-r--r--synapse/media/v1/thumbnailer.py89
-rw-r--r--synapse/media/v1/upload_resource.py113
-rw-r--r--synapse/notifier.py32
-rw-r--r--synapse/rest/__init__.py2
-rw-r--r--synapse/rest/admin.py2
-rw-r--r--synapse/rest/base.py4
-rw-r--r--synapse/rest/directory.py13
-rw-r--r--synapse/rest/login.py4
-rw-r--r--synapse/rest/presence.py9
-rw-r--r--synapse/rest/profile.py6
-rw-r--r--synapse/rest/register.py4
-rw-r--r--synapse/rest/room.py178
-rw-r--r--synapse/rest/transactions.py1
-rw-r--r--synapse/server.py32
-rw-r--r--synapse/state.py175
-rw-r--r--synapse/storage/__init__.py199
-rw-r--r--synapse/storage/_base.py158
-rw-r--r--synapse/storage/event_federation.py11
-rw-r--r--synapse/storage/media_repository.py129
-rw-r--r--synapse/storage/schema/delta/v9.sql79
-rw-r--r--synapse/storage/schema/im.sql13
-rw-r--r--synapse/storage/schema/media_repository.sql68
-rw-r--r--synapse/storage/schema/state.sql3
-rw-r--r--synapse/storage/schema/transactions.sql6
-rw-r--r--synapse/storage/signatures.py19
-rw-r--r--synapse/storage/state.py13
-rw-r--r--synapse/storage/transactions.py106
-rw-r--r--synapse/types.py21
-rw-r--r--synapse/util/frozenutils.py46
70 files changed, 3120 insertions, 1511 deletions
diff --git a/synapse/__init__.py b/synapse/__init__.py
index 7e49e1fd08..1cef40925f 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -16,4 +16,4 @@
 """ This is a reference implementation of a synapse home server.
 """
 
-__version__ = "0.5.4a"
+__version__ = "0.6.0"
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 2b0475543d..70245aba04 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -17,14 +17,10 @@
 
 from twisted.internet import defer
 
-from synapse.api.constants import Membership, JoinRules
+from synapse.api.constants import EventTypes, Membership, JoinRules
 from synapse.api.errors import AuthError, StoreError, Codes, SynapseError
-from synapse.api.events.room import (
-    RoomMemberEvent, RoomPowerLevelsEvent, RoomRedactionEvent,
-    RoomJoinRulesEvent, RoomCreateEvent, RoomAliasesEvent,
-)
 from synapse.util.logutils import log_function
-from syutil.base64util import encode_base64
+from synapse.util.async import run_on_reactor
 
 import logging
 
@@ -53,15 +49,17 @@ class Auth(object):
                 logger.warn("Trusting event: %s", event.event_id)
                 return True
 
-            if event.type == RoomCreateEvent.TYPE:
+            if event.type == EventTypes.Create:
                 # FIXME
                 return True
 
             # FIXME: Temp hack
-            if event.type == RoomAliasesEvent.TYPE:
+            if event.type == EventTypes.Aliases:
                 return True
 
-            if event.type == RoomMemberEvent.TYPE:
+            logger.debug("Auth events: %s", auth_events)
+
+            if event.type == EventTypes.Member:
                 allowed = self.is_membership_change_allowed(
                     event, auth_events
                 )
@@ -74,10 +72,10 @@ class Auth(object):
             self.check_event_sender_in_room(event, auth_events)
             self._can_send_event(event, auth_events)
 
-            if event.type == RoomPowerLevelsEvent.TYPE:
+            if event.type == EventTypes.PowerLevels:
                 self._check_power_levels(event, auth_events)
 
-            if event.type == RoomRedactionEvent.TYPE:
+            if event.type == EventTypes.Redaction:
                 self._check_redaction(event, auth_events)
 
             logger.debug("Allowing! %s", event)
@@ -93,7 +91,7 @@ class Auth(object):
     def check_joined_room(self, room_id, user_id):
         member = yield self.state.get_current_state(
             room_id=room_id,
-            event_type=RoomMemberEvent.TYPE,
+            event_type=EventTypes.Member,
             state_key=user_id
         )
         self._check_joined_room(member, user_id, room_id)
@@ -104,7 +102,7 @@ class Auth(object):
         curr_state = yield self.state.get_current_state(room_id)
 
         for event in curr_state:
-            if event.type == RoomMemberEvent.TYPE:
+            if event.type == EventTypes.Member:
                 try:
                     if self.hs.parse_userid(event.state_key).domain != host:
                         continue
@@ -118,7 +116,7 @@ class Auth(object):
         defer.returnValue(False)
 
     def check_event_sender_in_room(self, event, auth_events):
-        key = (RoomMemberEvent.TYPE, event.user_id, )
+        key = (EventTypes.Member, event.user_id, )
         member_event = auth_events.get(key)
 
         return self._check_joined_room(
@@ -140,7 +138,7 @@ class Auth(object):
         # Check if this is the room creator joining:
         if len(event.prev_events) == 1 and Membership.JOIN == membership:
             # Get room creation event:
-            key = (RoomCreateEvent.TYPE, "", )
+            key = (EventTypes.Create, "", )
             create = auth_events.get(key)
             if create and event.prev_events[0][0] == create.event_id:
                 if create.content["creator"] == event.state_key:
@@ -149,19 +147,19 @@ class Auth(object):
         target_user_id = event.state_key
 
         # get info about the caller
-        key = (RoomMemberEvent.TYPE, event.user_id, )
+        key = (EventTypes.Member, event.user_id, )
         caller = auth_events.get(key)
 
         caller_in_room = caller and caller.membership == Membership.JOIN
         caller_invited = caller and caller.membership == Membership.INVITE
 
         # get info about the target
-        key = (RoomMemberEvent.TYPE, target_user_id, )
+        key = (EventTypes.Member, target_user_id, )
         target = auth_events.get(key)
 
         target_in_room = target and target.membership == Membership.JOIN
 
-        key = (RoomJoinRulesEvent.TYPE, "", )
+        key = (EventTypes.JoinRules, "", )
         join_rule_event = auth_events.get(key)
         if join_rule_event:
             join_rule = join_rule_event.content.get(
@@ -256,7 +254,7 @@ class Auth(object):
         return True
 
     def _get_power_level_from_event_state(self, event, user_id, auth_events):
-        key = (RoomPowerLevelsEvent.TYPE, "", )
+        key = (EventTypes.PowerLevels, "", )
         power_level_event = auth_events.get(key)
         level = None
         if power_level_event:
@@ -264,7 +262,7 @@ class Auth(object):
             if not level:
                 level = power_level_event.content.get("users_default", 0)
         else:
-            key = (RoomCreateEvent.TYPE, "", )
+            key = (EventTypes.Create, "", )
             create_event = auth_events.get(key)
             if (create_event is not None and
                     create_event.content["creator"] == user_id):
@@ -273,7 +271,7 @@ class Auth(object):
         return level
 
     def _get_ops_level_from_event_state(self, event, auth_events):
-        key = (RoomPowerLevelsEvent.TYPE, "", )
+        key = (EventTypes.PowerLevels, "", )
         power_level_event = auth_events.get(key)
 
         if power_level_event:
@@ -351,29 +349,31 @@ class Auth(object):
         return self.store.is_server_admin(user)
 
     @defer.inlineCallbacks
-    def add_auth_events(self, event):
-        if event.type == RoomCreateEvent.TYPE:
-            event.auth_events = []
+    def add_auth_events(self, builder, context):
+        yield run_on_reactor()
+
+        if builder.type == EventTypes.Create:
+            builder.auth_events = []
             return
 
-        auth_events = []
+        auth_ids = []
 
-        key = (RoomPowerLevelsEvent.TYPE, "", )
-        power_level_event = event.old_state_events.get(key)
+        key = (EventTypes.PowerLevels, "", )
+        power_level_event = context.current_state.get(key)
 
         if power_level_event:
-            auth_events.append(power_level_event.event_id)
+            auth_ids.append(power_level_event.event_id)
 
-        key = (RoomJoinRulesEvent.TYPE, "", )
-        join_rule_event = event.old_state_events.get(key)
+        key = (EventTypes.JoinRules, "", )
+        join_rule_event = context.current_state.get(key)
 
-        key = (RoomMemberEvent.TYPE, event.user_id, )
-        member_event = event.old_state_events.get(key)
+        key = (EventTypes.Member, builder.user_id, )
+        member_event = context.current_state.get(key)
 
-        key = (RoomCreateEvent.TYPE, "", )
-        create_event = event.old_state_events.get(key)
+        key = (EventTypes.Create, "", )
+        create_event = context.current_state.get(key)
         if create_event:
-            auth_events.append(create_event.event_id)
+            auth_ids.append(create_event.event_id)
 
         if join_rule_event:
             join_rule = join_rule_event.content.get("join_rule")
@@ -381,33 +381,37 @@ class Auth(object):
         else:
             is_public = False
 
-        if event.type == RoomMemberEvent.TYPE:
-            e_type = event.content["membership"]
+        if builder.type == EventTypes.Member:
+            e_type = builder.content["membership"]
             if e_type in [Membership.JOIN, Membership.INVITE]:
                 if join_rule_event:
-                    auth_events.append(join_rule_event.event_id)
+                    auth_ids.append(join_rule_event.event_id)
 
+            if e_type == Membership.JOIN:
                 if member_event and not is_public:
-                    auth_events.append(member_event.event_id)
+                    auth_ids.append(member_event.event_id)
+            else:
+                if member_event:
+                    auth_ids.append(member_event.event_id)
         elif member_event:
             if member_event.content["membership"] == Membership.JOIN:
-                auth_events.append(member_event.event_id)
+                auth_ids.append(member_event.event_id)
 
-        hashes = yield self.store.get_event_reference_hashes(
-            auth_events
+        auth_events_entries = yield self.store.add_event_hashes(
+            auth_ids
         )
-        hashes = [
-            {
-                k: encode_base64(v) for k, v in h.items()
-                if k == "sha256"
-            }
-            for h in hashes
-        ]
-        event.auth_events = zip(auth_events, hashes)
+
+        builder.auth_events = auth_events_entries
+
+        context.auth_events = {
+            k: v
+            for k, v in context.current_state.items()
+            if v.event_id in auth_ids
+        }
 
     @log_function
     def _can_send_event(self, event, auth_events):
-        key = (RoomPowerLevelsEvent.TYPE, "", )
+        key = (EventTypes.PowerLevels, "", )
         send_level_event = auth_events.get(key)
         send_level = None
         if send_level_event:
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 3cafff0e32..4fc8b79a40 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -59,3 +59,18 @@ class LoginType(object):
     EMAIL_URL = u"m.login.email.url"
     EMAIL_IDENTITY = u"m.login.email.identity"
     RECAPTCHA = u"m.login.recaptcha"
+
+
+class EventTypes(object):
+    Member = "m.room.member"
+    Create = "m.room.create"
+    JoinRules = "m.room.join_rules"
+    PowerLevels = "m.room.power_levels"
+    Aliases = "m.room.aliases"
+    Redaction = "m.room.redaction"
+    Feedback = "m.room.message.feedback"
+
+    # These are used for validation
+    Message = "m.room.message"
+    Topic = "m.room.topic"
+    Name = "m.room.name"
diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index 64784bf212..5cda3a6953 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -34,7 +34,8 @@ class Codes(object):
     LIMIT_EXCEEDED = "M_LIMIT_EXCEEDED"
     CAPTCHA_NEEDED = "M_CAPTCHA_NEEDED"
     CAPTCHA_INVALID = "M_CAPTCHA_INVALID"
-    MISSING_PARAM = "M_MISSING_PARAM"
+    MISSING_PARAM = "M_MISSING_PARAM",
+    TOO_LARGE = "M_TOO_LARGE"
 
 
 class CodeMessageException(Exception):
diff --git a/synapse/api/events/__init__.py b/synapse/api/events/__init__.py
deleted file mode 100644
index 22939d011a..0000000000
--- a/synapse/api/events/__init__.py
+++ /dev/null
@@ -1,148 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2014 OpenMarket Ltd
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-from synapse.util.jsonobject import JsonEncodedObject
-
-
-def serialize_event(hs, e):
-    # FIXME(erikj): To handle the case of presence events and the like
-    if not isinstance(e, SynapseEvent):
-        return e
-
-    # Should this strip out None's?
-    d = {k: v for k, v in e.get_dict().items()}
-    if "age_ts" in d:
-        d["age"] = int(hs.get_clock().time_msec()) - d["age_ts"]
-        del d["age_ts"]
-
-    return d
-
-
-class SynapseEvent(JsonEncodedObject):
-
-    """Base class for Synapse events. These are JSON objects which must abide
-    by a certain well-defined structure.
-    """
-
-    # Attributes that are currently assumed by the federation side:
-    # Mandatory:
-    # - event_id
-    # - room_id
-    # - type
-    # - is_state
-    #
-    # Optional:
-    # - state_key (mandatory when is_state is True)
-    # - prev_events (these can be filled out by the federation layer itself.)
-    # - prev_state
-
-    valid_keys = [
-        "event_id",
-        "type",
-        "room_id",
-        "user_id",  # sender/initiator
-        "content",  # HTTP body, JSON
-        "state_key",
-        "age_ts",
-        "prev_content",
-        "replaces_state",
-        "redacted_because",
-        "origin_server_ts",
-    ]
-
-    internal_keys = [
-        "is_state",
-        "depth",
-        "destinations",
-        "origin",
-        "outlier",
-        "redacted",
-        "prev_events",
-        "hashes",
-        "signatures",
-        "prev_state",
-        "auth_events",
-        "state_hash",
-    ]
-
-    required_keys = [
-        "event_id",
-        "room_id",
-        "content",
-    ]
-
-    outlier = False
-
-    def __init__(self, raises=True, **kwargs):
-        super(SynapseEvent, self).__init__(**kwargs)
-        # if "content" in kwargs:
-        #     self.check_json(self.content, raises=raises)
-
-    def get_content_template(self):
-        """ Retrieve the JSON template for this event as a dict.
-
-        The template must be a dict representing the JSON to match. Only
-        required keys should be present. The values of the keys in the template
-        are checked via type() to the values of the same keys in the actual
-        event JSON.
-
-        NB: If loading content via json.loads, you MUST define strings as
-        unicode.
-
-        For example:
-            Content:
-                {
-                    "name": u"bob",
-                    "age": 18,
-                    "friends": [u"mike", u"jill"]
-                }
-            Template:
-                {
-                    "name": u"string",
-                    "age": 0,
-                    "friends": [u"string"]
-                }
-            The values "string" and 0 could be anything, so long as the types
-            are the same as the content.
-        """
-        raise NotImplementedError("get_content_template not implemented.")
-
-    def get_pdu_json(self, time_now=None):
-        pdu_json = self.get_full_dict()
-        pdu_json.pop("destinations", None)
-        pdu_json.pop("outlier", None)
-        pdu_json.pop("replaces_state", None)
-        pdu_json.pop("redacted", None)
-        pdu_json.pop("prev_content", None)
-        state_hash = pdu_json.pop("state_hash", None)
-        if state_hash is not None:
-            pdu_json.setdefault("unsigned", {})["state_hash"] = state_hash
-        content = pdu_json.get("content", {})
-        content.pop("prev", None)
-        if time_now is not None and "age_ts" in pdu_json:
-            age = time_now - pdu_json["age_ts"]
-            pdu_json.setdefault("unsigned", {})["age"] = int(age)
-            del pdu_json["age_ts"]
-        user_id = pdu_json.pop("user_id")
-        pdu_json["sender"] = user_id
-        return pdu_json
-
-
-class SynapseStateEvent(SynapseEvent):
-
-    def __init__(self, **kwargs):
-        if "state_key" not in kwargs:
-            kwargs["state_key"] = ""
-        super(SynapseStateEvent, self).__init__(**kwargs)
diff --git a/synapse/api/events/factory.py b/synapse/api/events/factory.py
deleted file mode 100644
index a1ec708a81..0000000000
--- a/synapse/api/events/factory.py
+++ /dev/null
@@ -1,90 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2014 OpenMarket Ltd
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-from synapse.api.events.room import (
-    RoomTopicEvent, MessageEvent, RoomMemberEvent, FeedbackEvent,
-    InviteJoinEvent, RoomConfigEvent, RoomNameEvent, GenericEvent,
-    RoomPowerLevelsEvent, RoomJoinRulesEvent,
-    RoomCreateEvent,
-    RoomRedactionEvent,
-)
-
-from synapse.types import EventID
-
-from synapse.util.stringutils import random_string
-
-
-class EventFactory(object):
-
-    _event_classes = [
-        RoomTopicEvent,
-        RoomNameEvent,
-        MessageEvent,
-        RoomMemberEvent,
-        FeedbackEvent,
-        InviteJoinEvent,
-        RoomConfigEvent,
-        RoomPowerLevelsEvent,
-        RoomJoinRulesEvent,
-        RoomCreateEvent,
-        RoomRedactionEvent,
-    ]
-
-    def __init__(self, hs):
-        self._event_list = {}  # dict of TYPE to event class
-        for event_class in EventFactory._event_classes:
-            self._event_list[event_class.TYPE] = event_class
-
-        self.clock = hs.get_clock()
-        self.hs = hs
-
-        self.event_id_count = 0
-
-    def create_event_id(self):
-        i = str(self.event_id_count)
-        self.event_id_count += 1
-
-        local_part = str(int(self.clock.time())) + i + random_string(5)
-
-        e_id = EventID.create_local(local_part, self.hs)
-
-        return e_id.to_string()
-
-    def create_event(self, etype=None, **kwargs):
-        kwargs["type"] = etype
-        if "event_id" not in kwargs:
-            kwargs["event_id"] = self.create_event_id()
-            kwargs["origin"] = self.hs.hostname
-        else:
-            ev_id = self.hs.parse_eventid(kwargs["event_id"])
-            kwargs["origin"] = ev_id.domain
-
-        if "origin_server_ts" not in kwargs:
-            kwargs["origin_server_ts"] = int(self.clock.time_msec())
-
-        # The "age" key is a delta timestamp that should be converted into an
-        # absolute timestamp the minute we see it.
-        if "age" in kwargs:
-            kwargs["age_ts"] = int(self.clock.time_msec()) - int(kwargs["age"])
-            del kwargs["age"]
-        elif "age_ts" not in kwargs:
-            kwargs["age_ts"] = int(self.clock.time_msec())
-
-        if etype in self._event_list:
-            handler = self._event_list[etype]
-        else:
-            handler = GenericEvent
-
-        return handler(**kwargs)
diff --git a/synapse/api/events/room.py b/synapse/api/events/room.py
deleted file mode 100644
index 8c4ac45d02..0000000000
--- a/synapse/api/events/room.py
+++ /dev/null
@@ -1,170 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2014 OpenMarket Ltd
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-from synapse.api.constants import Feedback, Membership
-from synapse.api.errors import SynapseError
-from . import SynapseEvent, SynapseStateEvent
-
-
-class GenericEvent(SynapseEvent):
-    def get_content_template(self):
-        return {}
-
-
-class RoomTopicEvent(SynapseEvent):
-    TYPE = "m.room.topic"
-
-    internal_keys = SynapseEvent.internal_keys + [
-        "topic",
-    ]
-
-    def __init__(self, **kwargs):
-        kwargs["state_key"] = ""
-        if "topic" in kwargs["content"]:
-            kwargs["topic"] = kwargs["content"]["topic"]
-        super(RoomTopicEvent, self).__init__(**kwargs)
-
-    def get_content_template(self):
-        return {"topic": u"string"}
-
-
-class RoomNameEvent(SynapseEvent):
-    TYPE = "m.room.name"
-
-    internal_keys = SynapseEvent.internal_keys + [
-        "name",
-    ]
-
-    def __init__(self, **kwargs):
-        kwargs["state_key"] = ""
-        if "name" in kwargs["content"]:
-            kwargs["name"] = kwargs["content"]["name"]
-        super(RoomNameEvent, self).__init__(**kwargs)
-
-    def get_content_template(self):
-        return {"name": u"string"}
-
-
-class RoomMemberEvent(SynapseEvent):
-    TYPE = "m.room.member"
-
-    valid_keys = SynapseEvent.valid_keys + [
-        # target is the state_key
-        "membership",  # action
-    ]
-
-    def __init__(self, **kwargs):
-        if "membership" not in kwargs:
-            kwargs["membership"] = kwargs.get("content", {}).get("membership")
-        if not kwargs["membership"] in Membership.LIST:
-            raise SynapseError(400, "Bad membership value.")
-        super(RoomMemberEvent, self).__init__(**kwargs)
-
-    def get_content_template(self):
-        return {"membership": u"string"}
-
-
-class MessageEvent(SynapseEvent):
-    TYPE = "m.room.message"
-
-    valid_keys = SynapseEvent.valid_keys + [
-        "msg_id",  # unique per room + user combo
-    ]
-
-    def __init__(self, **kwargs):
-        super(MessageEvent, self).__init__(**kwargs)
-
-    def get_content_template(self):
-        return {"msgtype": u"string"}
-
-
-class FeedbackEvent(SynapseEvent):
-    TYPE = "m.room.message.feedback"
-
-    valid_keys = SynapseEvent.valid_keys
-
-    def __init__(self, **kwargs):
-        super(FeedbackEvent, self).__init__(**kwargs)
-        if not kwargs["content"]["type"] in Feedback.LIST:
-            raise SynapseError(400, "Bad feedback value.")
-
-    def get_content_template(self):
-        return {
-            "type": u"string",
-            "target_event_id": u"string"
-        }
-
-
-class InviteJoinEvent(SynapseEvent):
-    TYPE = "m.room.invite_join"
-
-    valid_keys = SynapseEvent.valid_keys + [
-        # target_user_id is the state_key
-        "target_host",
-    ]
-
-    def __init__(self, **kwargs):
-        super(InviteJoinEvent, self).__init__(**kwargs)
-
-    def get_content_template(self):
-        return {}
-
-
-class RoomConfigEvent(SynapseEvent):
-    TYPE = "m.room.config"
-
-    def __init__(self, **kwargs):
-        kwargs["state_key"] = ""
-        super(RoomConfigEvent, self).__init__(**kwargs)
-
-    def get_content_template(self):
-        return {}
-
-
-class RoomCreateEvent(SynapseStateEvent):
-    TYPE = "m.room.create"
-
-    def get_content_template(self):
-        return {}
-
-
-class RoomJoinRulesEvent(SynapseStateEvent):
-    TYPE = "m.room.join_rules"
-
-    def get_content_template(self):
-        return {}
-
-
-class RoomPowerLevelsEvent(SynapseStateEvent):
-    TYPE = "m.room.power_levels"
-
-    def get_content_template(self):
-        return {}
-
-
-class RoomAliasesEvent(SynapseStateEvent):
-    TYPE = "m.room.aliases"
-
-    def get_content_template(self):
-        return {}
-
-
-class RoomRedactionEvent(SynapseEvent):
-    TYPE = "m.room.redaction"
-
-    valid_keys = SynapseEvent.valid_keys + ["redacts"]
-
-    def get_content_template(self):
-        return {}
diff --git a/synapse/api/events/validator.py b/synapse/api/events/validator.py
deleted file mode 100644
index 067215f6ef..0000000000
--- a/synapse/api/events/validator.py
+++ /dev/null
@@ -1,87 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2014 OpenMarket Ltd
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-from synapse.api.errors import SynapseError, Codes
-
-
-class EventValidator(object):
-    def __init__(self, hs):
-        pass
-
-    def validate(self, event):
-        """Checks the given JSON content abides by the rules of the template.
-
-        Args:
-            content : A JSON object to check.
-            raises: True to raise a SynapseError if the check fails.
-        Returns:
-            True if the content passes the template. Returns False if the check
-            fails and raises=False.
-        Raises:
-            SynapseError if the check fails and raises=True.
-        """
-        # recursively call to inspect each layer
-        err_msg = self._check_json_template(
-            event.content,
-            event.get_content_template()
-        )
-        if err_msg:
-            raise SynapseError(400, err_msg, Codes.BAD_JSON)
-        else:
-            return True
-
-    def _check_json_template(self, content, template):
-        """Check content and template matches.
-
-        If the template is a dict, each key in the dict will be validated with
-        the content, else it will just compare the types of content and
-        template. This basic type check is required because this function will
-        be recursively called and could be called with just strs or ints.
-
-        Args:
-            content: The content to validate.
-            template: The validation template.
-        Returns:
-            str: An error message if the validation fails, else None.
-        """
-        if type(content) != type(template):
-            return "Mismatched types: %s" % template
-
-        if type(template) == dict:
-            for key in template:
-                if key not in content:
-                    return "Missing %s key" % key
-
-                if type(content[key]) != type(template[key]):
-                    return "Key %s is of the wrong type (got %s, want %s)" % (
-                        key, type(content[key]), type(template[key]))
-
-                if type(content[key]) == dict:
-                    # we must go deeper
-                    msg = self._check_json_template(
-                        content[key],
-                        template[key]
-                    )
-                    if msg:
-                        return msg
-                elif type(content[key]) == list:
-                    # make sure each item type in content matches the template
-                    for entry in content[key]:
-                        msg = self._check_json_template(
-                            entry,
-                            template[key][0]
-                        )
-                        if msg:
-                            return msg
diff --git a/synapse/api/urls.py b/synapse/api/urls.py
index 6dc19305b7..d7625127f8 100644
--- a/synapse/api/urls.py
+++ b/synapse/api/urls.py
@@ -20,3 +20,4 @@ FEDERATION_PREFIX = "/_matrix/federation/v1"
 WEB_CLIENT_PREFIX = "/_matrix/client"
 CONTENT_REPO_PREFIX = "/_matrix/content"
 SERVER_KEY_PREFIX = "/_matrix/key/v1"
+MEDIA_PREFIX = "/_matrix/media/v1"
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index d24c934b3f..ea52259724 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage import prepare_database
+from synapse.storage import prepare_database, UpgradeDatabaseException
 
 from synapse.server import HomeServer
 
@@ -24,12 +24,13 @@ from twisted.web.resource import Resource
 from twisted.web.static import File
 from twisted.web.server import Site
 from synapse.http.server import JsonResource, RootRedirect
-from synapse.http.content_repository import ContentRepoResource
+from synapse.media.v0.content_repository import ContentRepoResource
+from synapse.media.v1.media_repository import MediaRepositoryResource
 from synapse.http.server_key_resource import LocalKey
 from synapse.http.matrixfederationclient import MatrixFederationHttpClient
 from synapse.api.urls import (
     CLIENT_PREFIX, FEDERATION_PREFIX, WEB_CLIENT_PREFIX, CONTENT_REPO_PREFIX,
-    SERVER_KEY_PREFIX,
+    SERVER_KEY_PREFIX, MEDIA_PREFIX
 )
 from synapse.config.homeserver import HomeServerConfig
 from synapse.crypto import context_factory
@@ -69,6 +70,9 @@ class SynapseHomeServer(HomeServer):
             self, self.upload_dir, self.auth, self.content_addr
         )
 
+    def build_resource_for_media_repository(self):
+        return MediaRepositoryResource(self)
+
     def build_resource_for_server_key(self):
         return LocalKey(self)
 
@@ -99,6 +103,7 @@ class SynapseHomeServer(HomeServer):
             (FEDERATION_PREFIX, self.get_resource_for_federation()),
             (CONTENT_REPO_PREFIX, self.get_resource_for_content_repo()),
             (SERVER_KEY_PREFIX, self.get_resource_for_server_key()),
+            (MEDIA_PREFIX, self.get_resource_for_media_repository()),
         ]
         if web_client:
             logger.info("Adding the web client.")
@@ -223,8 +228,15 @@ def setup():
 
     logger.info("Preparing database: %s...", db_name)
 
-    with sqlite3.connect(db_name) as db_conn:
-        prepare_database(db_conn)
+    try:
+        with sqlite3.connect(db_name) as db_conn:
+            prepare_database(db_conn)
+    except UpgradeDatabaseException:
+        sys.stderr.write(
+            "\nFailed to upgrade database.\n"
+            "Have you followed any instructions in UPGRADES.rst?\n"
+        )
+        sys.exit(1)
 
     logger.info("Database prepared in %s.", db_name)
 
diff --git a/synapse/config/_base.py b/synapse/config/_base.py
index 846570811f..1cdd03e414 100644
--- a/synapse/config/_base.py
+++ b/synapse/config/_base.py
@@ -50,6 +50,16 @@ class Config(object):
             )
         return cls.abspath(file_path)
 
+    @staticmethod
+    def ensure_directory(dir_path):
+        if not os.path.exists(dir_path):
+            os.makedirs(dir_path)
+        if not os.path.isdir(dir_path):
+            raise ConfigError(
+                "%s is not a directory" % (dir_path,)
+            )
+        return dir_path
+
     @classmethod
     def read_file(cls, file_path, config_name):
         cls.check_file(file_path, config_name)
@@ -57,6 +67,10 @@ class Config(object):
             return file_stream.read()
 
     @staticmethod
+    def default_path(name):
+        return os.path.abspath(os.path.join(os.path.curdir, name))
+
+    @staticmethod
     def read_config_file(file_path):
         with open(file_path) as file_stream:
             return yaml.load(file_stream)
diff --git a/synapse/config/logger.py b/synapse/config/logger.py
index 089d906fa5..d352ea9be9 100644
--- a/synapse/config/logger.py
+++ b/synapse/config/logger.py
@@ -36,7 +36,7 @@ class LoggingConfig(Config):
             help="The verbosity level."
         )
         logging_group.add_argument(
-            '-f', '--log-file', dest="log_file", default=None,
+            '-f', '--log-file', dest="log_file", default="homeserver.log",
             help="File to log to."
         )
         logging_group.add_argument(
diff --git a/synapse/config/repository.py b/synapse/config/repository.py
index 743bc26474..f1b7b1b74e 100644
--- a/synapse/config/repository.py
+++ b/synapse/config/repository.py
@@ -20,6 +20,8 @@ class ContentRepositoryConfig(Config):
     def __init__(self, args):
         super(ContentRepositoryConfig, self).__init__(args)
         self.max_upload_size = self.parse_size(args.max_upload_size)
+        self.max_image_pixels = self.parse_size(args.max_image_pixels)
+        self.media_store_path = self.ensure_directory(args.media_store_path)
 
     def parse_size(self, string):
         sizes = {"K": 1024, "M": 1024 * 1024}
@@ -37,3 +39,10 @@ class ContentRepositoryConfig(Config):
         db_group.add_argument(
             "--max-upload-size", default="1M"
         )
+        db_group.add_argument(
+            "--media-store-path", default=cls.default_path("media_store")
+        )
+        db_group.add_argument(
+            "--max-image-pixels", default="32M",
+            help="Maximum number of pixels that will be thumbnailed"
+        )
diff --git a/synapse/crypto/event_signing.py b/synapse/crypto/event_signing.py
index a9d8953239..21c19c971d 100644
--- a/synapse/crypto/event_signing.py
+++ b/synapse/crypto/event_signing.py
@@ -15,7 +15,7 @@
 # limitations under the License.
 
 
-from synapse.api.events.utils import prune_event
+from synapse.events.utils import prune_event
 from syutil.jsonutil import encode_canonical_json
 from syutil.base64util import encode_base64, decode_base64
 from syutil.crypto.jsonsign import sign_json
@@ -29,17 +29,17 @@ logger = logging.getLogger(__name__)
 
 def check_event_content_hash(event, hash_algorithm=hashlib.sha256):
     """Check whether the hash for this PDU matches the contents"""
-    computed_hash = _compute_content_hash(event, hash_algorithm)
-    logger.debug("Expecting hash: %s", encode_base64(computed_hash.digest()))
-    if computed_hash.name not in event.hashes:
+    name, expected_hash = compute_content_hash(event, hash_algorithm)
+    logger.debug("Expecting hash: %s", encode_base64(expected_hash))
+    if name not in event.hashes:
         raise SynapseError(
             400,
             "Algorithm %s not in hashes %s" % (
-                computed_hash.name, list(event.hashes),
+                name, list(event.hashes),
             ),
             Codes.UNAUTHORIZED,
         )
-    message_hash_base64 = event.hashes[computed_hash.name]
+    message_hash_base64 = event.hashes[name]
     try:
         message_hash_bytes = decode_base64(message_hash_base64)
     except:
@@ -48,10 +48,10 @@ def check_event_content_hash(event, hash_algorithm=hashlib.sha256):
             "Invalid base64: %s" % (message_hash_base64,),
             Codes.UNAUTHORIZED,
         )
-    return message_hash_bytes == computed_hash.digest()
+    return message_hash_bytes == expected_hash
 
 
-def _compute_content_hash(event, hash_algorithm):
+def compute_content_hash(event, hash_algorithm):
     event_json = event.get_pdu_json()
     event_json.pop("age_ts", None)
     event_json.pop("unsigned", None)
@@ -59,8 +59,11 @@ def _compute_content_hash(event, hash_algorithm):
     event_json.pop("hashes", None)
     event_json.pop("outlier", None)
     event_json.pop("destinations", None)
+
     event_json_bytes = encode_canonical_json(event_json)
-    return hash_algorithm(event_json_bytes)
+
+    hashed = hash_algorithm(event_json_bytes)
+    return (hashed.name, hashed.digest())
 
 
 def compute_event_reference_hash(event, hash_algorithm=hashlib.sha256):
@@ -79,27 +82,28 @@ def compute_event_signature(event, signature_name, signing_key):
     redact_json = tmp_event.get_pdu_json()
     redact_json.pop("age_ts", None)
     redact_json.pop("unsigned", None)
-    logger.debug("Signing event: %s", redact_json)
+    logger.debug("Signing event: %s", encode_canonical_json(redact_json))
     redact_json = sign_json(redact_json, signature_name, signing_key)
+    logger.debug("Signed event: %s", encode_canonical_json(redact_json))
     return redact_json["signatures"]
 
 
 def add_hashes_and_signatures(event, signature_name, signing_key,
                               hash_algorithm=hashlib.sha256):
-    if hasattr(event, "old_state_events"):
-        state_json_bytes = encode_canonical_json(
-            [e.event_id for e in event.old_state_events.values()]
-        )
-        hashed = hash_algorithm(state_json_bytes)
-        event.state_hash = {
-            hashed.name: encode_base64(hashed.digest())
-        }
+    # if hasattr(event, "old_state_events"):
+    #     state_json_bytes = encode_canonical_json(
+    #         [e.event_id for e in event.old_state_events.values()]
+    #     )
+    #     hashed = hash_algorithm(state_json_bytes)
+    #     event.state_hash = {
+    #         hashed.name: encode_base64(hashed.digest())
+    #     }
 
-    hashed = _compute_content_hash(event, hash_algorithm=hash_algorithm)
+    name, digest = compute_content_hash(event, hash_algorithm=hash_algorithm)
 
     if not hasattr(event, "hashes"):
         event.hashes = {}
-    event.hashes[hashed.name] = encode_base64(hashed.digest())
+    event.hashes[name] = encode_base64(digest)
 
     event.signatures = compute_event_signature(
         event,
diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py
new file mode 100644
index 0000000000..34b1b944ab
--- /dev/null
+++ b/synapse/events/__init__.py
@@ -0,0 +1,149 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from synapse.util.frozenutils import freeze, unfreeze
+
+import copy
+
+
+class _EventInternalMetadata(object):
+    def __init__(self, internal_metadata_dict):
+        self.__dict__ = copy.deepcopy(internal_metadata_dict)
+
+    def get_dict(self):
+        return dict(self.__dict__)
+
+    def is_outlier(self):
+        return hasattr(self, "outlier") and self.outlier
+
+
+def _event_dict_property(key):
+    def getter(self):
+        return self._event_dict[key]
+
+    def setter(self, v):
+        self._event_dict[key] = v
+
+    def delete(self):
+        del self._event_dict[key]
+
+    return property(
+        getter,
+        setter,
+        delete,
+    )
+
+
+class EventBase(object):
+    def __init__(self, event_dict, signatures={}, unsigned={},
+                 internal_metadata_dict={}):
+        self.signatures = copy.deepcopy(signatures)
+        self.unsigned = copy.deepcopy(unsigned)
+
+        self._event_dict = copy.deepcopy(event_dict)
+
+        self.internal_metadata = _EventInternalMetadata(
+            internal_metadata_dict
+        )
+
+    auth_events = _event_dict_property("auth_events")
+    depth = _event_dict_property("depth")
+    content = _event_dict_property("content")
+    event_id = _event_dict_property("event_id")
+    hashes = _event_dict_property("hashes")
+    origin = _event_dict_property("origin")
+    origin_server_ts = _event_dict_property("origin_server_ts")
+    prev_events = _event_dict_property("prev_events")
+    prev_state = _event_dict_property("prev_state")
+    redacts = _event_dict_property("redacts")
+    room_id = _event_dict_property("room_id")
+    sender = _event_dict_property("sender")
+    state_key = _event_dict_property("state_key")
+    type = _event_dict_property("type")
+    user_id = _event_dict_property("sender")
+
+    @property
+    def membership(self):
+        return self.content["membership"]
+
+    def is_state(self):
+        return hasattr(self, "state_key")
+
+    def get_dict(self):
+        d = dict(self._event_dict)
+        d.update({
+            "signatures": self.signatures,
+            "unsigned": self.unsigned,
+        })
+
+        return d
+
+    def get(self, key, default):
+        return self._event_dict.get(key, default)
+
+    def get_internal_metadata_dict(self):
+        return self.internal_metadata.get_dict()
+
+    def get_pdu_json(self, time_now=None):
+        pdu_json = self.get_dict()
+
+        if time_now is not None and "age_ts" in pdu_json["unsigned"]:
+            age = time_now - pdu_json["unsigned"]["age_ts"]
+            pdu_json.setdefault("unsigned", {})["age"] = int(age)
+            del pdu_json["unsigned"]["age_ts"]
+
+        return pdu_json
+
+    def __set__(self, instance, value):
+        raise AttributeError("Unrecognized attribute %s" % (instance,))
+
+
+class FrozenEvent(EventBase):
+    def __init__(self, event_dict, internal_metadata_dict={}):
+        event_dict = copy.deepcopy(event_dict)
+
+        signatures = copy.deepcopy(event_dict.pop("signatures", {}))
+        unsigned = copy.deepcopy(event_dict.pop("unsigned", {}))
+
+        frozen_dict = freeze(event_dict)
+
+        super(FrozenEvent, self).__init__(
+            frozen_dict,
+            signatures=signatures,
+            unsigned=unsigned,
+            internal_metadata_dict=internal_metadata_dict,
+        )
+
+    @staticmethod
+    def from_event(event):
+        e = FrozenEvent(
+            event.get_pdu_json()
+        )
+
+        e.internal_metadata = event.internal_metadata
+
+        return e
+
+    def get_dict(self):
+        # We need to unfreeze what we return
+        return unfreeze(super(FrozenEvent, self).get_dict())
+
+    def __str__(self):
+        return self.__repr__()
+
+    def __repr__(self):
+        return "<FrozenEvent event_id='%s', type='%s', state_key='%s'>" % (
+            self.event_id, self.type, self.get("state_key", None),
+        )
diff --git a/synapse/events/builder.py b/synapse/events/builder.py
new file mode 100644
index 0000000000..9579b1fe8b
--- /dev/null
+++ b/synapse/events/builder.py
@@ -0,0 +1,77 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from . import EventBase, FrozenEvent
+
+from synapse.types import EventID
+
+from synapse.util.stringutils import random_string
+
+import copy
+
+
+class EventBuilder(EventBase):
+    def __init__(self, key_values={}):
+        signatures = copy.deepcopy(key_values.pop("signatures", {}))
+        unsigned = copy.deepcopy(key_values.pop("unsigned", {}))
+
+        super(EventBuilder, self).__init__(
+            key_values,
+            signatures=signatures,
+            unsigned=unsigned
+        )
+
+    def update_event_key(self, key, value):
+        self._event_dict[key] = value
+
+    def update_event_keys(self, other_dict):
+        self._event_dict.update(other_dict)
+
+    def build(self):
+        return FrozenEvent.from_event(self)
+
+
+class EventBuilderFactory(object):
+    def __init__(self, clock, hostname):
+        self.clock = clock
+        self.hostname = hostname
+
+        self.event_id_count = 0
+
+    def create_event_id(self):
+        i = str(self.event_id_count)
+        self.event_id_count += 1
+
+        local_part = str(int(self.clock.time())) + i + random_string(5)
+
+        e_id = EventID.create(local_part, self.hostname)
+
+        return e_id.to_string()
+
+    def new(self, key_values={}):
+        key_values["event_id"] = self.create_event_id()
+
+        time_now = int(self.clock.time_msec())
+
+        key_values.setdefault("origin", self.hostname)
+        key_values.setdefault("origin_server_ts", time_now)
+
+        key_values.setdefault("unsigned", {})
+        age = key_values["unsigned"].pop("age", 0)
+        key_values["unsigned"].setdefault("age_ts", time_now - age)
+
+        key_values["signatures"] = {}
+
+        return EventBuilder(key_values=key_values,)
diff --git a/tests/events/__init__.py b/synapse/events/snapshot.py
index 9bff9ec169..b9fb29be01 100644
--- a/tests/events/__init__.py
+++ b/synapse/events/snapshot.py
@@ -13,3 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+
+class EventContext(object):
+
+    def __init__(self, current_state=None, auth_events=None):
+        self.current_state = current_state
+        self.auth_events = auth_events
+        self.state_group = None
diff --git a/synapse/api/events/utils.py b/synapse/events/utils.py
index d6019d56eb..94f3f15f52 100644
--- a/synapse/api/events/utils.py
+++ b/synapse/events/utils.py
@@ -13,10 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .room import (
-    RoomMemberEvent, RoomJoinRulesEvent, RoomPowerLevelsEvent,
-    RoomAliasesEvent, RoomCreateEvent,
-)
+from synapse.api.constants import EventTypes
+from . import EventBase
 
 
 def prune_event(event):
@@ -31,7 +29,7 @@ def prune_event(event):
 
     allowed_keys = [
         "event_id",
-        "user_id",
+        "sender",
         "room_id",
         "hashes",
         "signatures",
@@ -44,6 +42,7 @@ def prune_event(event):
         "auth_events",
         "origin",
         "origin_server_ts",
+        "membership",
     ]
 
     new_content = {}
@@ -53,13 +52,13 @@ def prune_event(event):
             if field in event.content:
                 new_content[field] = event.content[field]
 
-    if event_type == RoomMemberEvent.TYPE:
+    if event_type == EventTypes.Member:
         add_fields("membership")
-    elif event_type == RoomCreateEvent.TYPE:
+    elif event_type == EventTypes.Create:
         add_fields("creator")
-    elif event_type == RoomJoinRulesEvent.TYPE:
+    elif event_type == EventTypes.JoinRules:
         add_fields("join_rule")
-    elif event_type == RoomPowerLevelsEvent.TYPE:
+    elif event_type == EventTypes.PowerLevels:
         add_fields(
             "users",
             "users_default",
@@ -71,15 +70,61 @@ def prune_event(event):
             "kick",
             "redact",
         )
-    elif event_type == RoomAliasesEvent.TYPE:
+    elif event_type == EventTypes.Aliases:
         add_fields("aliases")
 
     allowed_fields = {
         k: v
-        for k, v in event.get_full_dict().items()
+        for k, v in event.get_dict().items()
         if k in allowed_keys
     }
 
     allowed_fields["content"] = new_content
 
-    return type(event)(**allowed_fields)
+    allowed_fields["unsigned"] = {}
+
+    if "age_ts" in event.unsigned:
+        allowed_fields["unsigned"]["age_ts"] = event.unsigned["age_ts"]
+
+    return type(event)(allowed_fields)
+
+
+def serialize_event(hs, e):
+    # FIXME(erikj): To handle the case of presence events and the like
+    if not isinstance(e, EventBase):
+        return e
+
+    # Should this strip out None's?
+    d = {k: v for k, v in e.get_dict().items()}
+    if "age_ts" in d["unsigned"]:
+        now = int(hs.get_clock().time_msec())
+        d["unsigned"]["age"] = now - d["unsigned"]["age_ts"]
+        del d["unsigned"]["age_ts"]
+
+    d["user_id"] = d.pop("sender", None)
+
+    if "redacted_because" in e.unsigned:
+        d["redacted_because"] = serialize_event(
+            hs, e.unsigned["redacted_because"]
+        )
+
+        del d["unsigned"]["redacted_because"]
+
+    if "redacted_by" in e.unsigned:
+        d["redacted_by"] = e.unsigned["redacted_by"]
+        del d["unsigned"]["redacted_by"]
+
+    if "replaces_state" in e.unsigned:
+        d["replaces_state"] = e.unsigned["replaces_state"]
+        del d["unsigned"]["replaces_state"]
+
+    if "prev_content" in e.unsigned:
+        d["prev_content"] = e.unsigned["prev_content"]
+        del d["unsigned"]["prev_content"]
+
+    del d["auth_events"]
+    del d["prev_events"]
+    del d["hashes"]
+    del d["signatures"]
+
+    return d
diff --git a/synapse/events/validator.py b/synapse/events/validator.py
new file mode 100644
index 0000000000..ebc6c30e62
--- /dev/null
+++ b/synapse/events/validator.py
@@ -0,0 +1,92 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from synapse.types import EventID, RoomID, UserID
+from synapse.api.errors import SynapseError
+from synapse.api.constants import EventTypes, Membership
+
+
+class EventValidator(object):
+
+    def validate(self, event):
+        EventID.from_string(event.event_id)
+        RoomID.from_string(event.room_id)
+
+        required = [
+            # "auth_events",
+            "content",
+            # "hashes",
+            "origin",
+            # "prev_events",
+            "sender",
+            "type",
+        ]
+
+        for k in required:
+            if not hasattr(event, k):
+                raise SynapseError(400, "Event does not have key %s" % (k,))
+
+        # Check that the following keys have string values
+        strings = [
+            "origin",
+            "sender",
+            "type",
+        ]
+
+        if hasattr(event, "state_key"):
+            strings.append("state_key")
+
+        for s in strings:
+            if not isinstance(getattr(event, s), basestring):
+                raise SynapseError(400, "Not '%s' a string type" % (s,))
+
+        if event.type == EventTypes.Member:
+            if "membership" not in event.content:
+                raise SynapseError(400, "Content has not membership key")
+
+            if event.content["membership"] not in Membership.LIST:
+                raise SynapseError(400, "Invalid membership key")
+
+        # Check that the following keys have dictionary values
+        # TODO
+
+        # Check that the following keys have the correct format for DAGs
+        # TODO
+
+    def validate_new(self, event):
+        self.validate(event)
+
+        UserID.from_string(event.sender)
+
+        if event.type == EventTypes.Message:
+            strings = [
+                "body",
+                "msgtype",
+            ]
+
+            self._ensure_strings(event.content, strings)
+
+        elif event.type == EventTypes.Topic:
+            self._ensure_strings(event.content, ["topic"])
+
+        elif event.type == EventTypes.Name:
+            self._ensure_strings(event.content, ["name"])
+
+    def _ensure_strings(self, d, keys):
+        for s in keys:
+            if s not in d:
+                raise SynapseError(400, "'%s' not in content" % (s,))
+            if not isinstance(d[s], basestring):
+                raise SynapseError(400, "Not '%s' a string type" % (s,))
diff --git a/synapse/federation/replication.py b/synapse/federation/replication.py
index 01f87fe423..9f8aadccca 100644
--- a/synapse/federation/replication.py
+++ b/synapse/federation/replication.py
@@ -25,6 +25,7 @@ from .persistence import TransactionActions
 
 from synapse.util.logutils import log_function
 from synapse.util.logcontext import PreserveLoggingContext
+from synapse.events import FrozenEvent
 
 import logging
 
@@ -73,7 +74,7 @@ class ReplicationLayer(object):
 
         self._clock = hs.get_clock()
 
-        self.event_factory = hs.get_event_factory()
+        self.event_builder_factory = hs.get_event_builder_factory()
 
     def set_handler(self, handler):
         """Sets the handler that the replication layer will use to communicate
@@ -112,7 +113,7 @@ class ReplicationLayer(object):
         self.query_handlers[query_type] = handler
 
     @log_function
-    def send_pdu(self, pdu):
+    def send_pdu(self, pdu, destinations):
         """Informs the replication layer about a new PDU generated within the
         home server that should be transmitted to others.
 
@@ -131,7 +132,7 @@ class ReplicationLayer(object):
         logger.debug("[%s] transaction_layer.enqueue_pdu... ", pdu.event_id)
 
         # TODO, add errback, etc.
-        self._transaction_queue.enqueue_pdu(pdu, order)
+        self._transaction_queue.enqueue_pdu(pdu, destinations, order)
 
         logger.debug(
             "[%s] transaction_layer.enqueue_pdu... done",
@@ -334,7 +335,7 @@ class ReplicationLayer(object):
             defer.returnValue(response)
             return
 
-        logger.debug("[%s] Transacition is new", transaction.transaction_id)
+        logger.debug("[%s] Transaction is new", transaction.transaction_id)
 
         with PreserveLoggingContext():
             dl = []
@@ -438,7 +439,9 @@ class ReplicationLayer(object):
 
     @defer.inlineCallbacks
     def on_send_join_request(self, origin, content):
+        logger.debug("on_send_join_request: content: %s", content)
         pdu = self.event_from_pdu_json(content)
+        logger.debug("on_send_join_request: pdu sigs: %s", pdu.signatures)
         res_pdus = yield self.handler.on_send_join_request(origin, pdu)
         time_now = self._clock.time_msec()
         defer.returnValue((200, {
@@ -557,7 +560,13 @@ class ReplicationLayer(object):
             origin, pdu.event_id, do_auth=False
         )
 
-        if existing and (not existing.outlier or pdu.outlier):
+        already_seen = (
+            existing and (
+                not existing.internal_metadata.outlier
+                or pdu.internal_metadata.outlier
+            )
+        )
+        if already_seen:
             logger.debug("Already seen pdu %s", pdu.event_id)
             defer.returnValue({})
             return
@@ -595,7 +604,7 @@ class ReplicationLayer(object):
         #             )
 
         # Get missing pdus if necessary.
-        if not pdu.outlier:
+        if not pdu.internal_metadata.outlier:
             # We only backfill backwards to the min depth.
             min_depth = yield self.handler.get_min_depth_for_context(
                 pdu.room_id
@@ -658,19 +667,14 @@ class ReplicationLayer(object):
         return "<ReplicationLayer(%s)>" % self.server_name
 
     def event_from_pdu_json(self, pdu_json, outlier=False):
-        #TODO: Check we have all the PDU keys here
-        pdu_json.setdefault("hashes", {})
-        pdu_json.setdefault("signatures", {})
-        sender = pdu_json.pop("sender", None)
-        if sender is not None:
-            pdu_json["user_id"] = sender
-        state_hash = pdu_json.get("unsigned", {}).pop("state_hash", None)
-        if state_hash is not None:
-            pdu_json["state_hash"] = state_hash
-        return self.event_factory.create_event(
-            pdu_json["type"], outlier=outlier, **pdu_json
+        event = FrozenEvent(
+            pdu_json
         )
 
+        event.internal_metadata.outlier = outlier
+
+        return event
+
 
 class _TransactionQueue(object):
     """This class makes sure we only have one transaction in flight at
@@ -685,6 +689,7 @@ class _TransactionQueue(object):
         self.transport_layer = transport_layer
 
         self._clock = hs.get_clock()
+        self.store = hs.get_datastore()
 
         # Is a mapping from destinations -> deferreds. Used to keep track
         # of which destinations have transactions in flight and when they are
@@ -705,15 +710,13 @@ class _TransactionQueue(object):
 
     @defer.inlineCallbacks
     @log_function
-    def enqueue_pdu(self, pdu, order):
+    def enqueue_pdu(self, pdu, destinations, order):
         # We loop through all destinations to see whether we already have
         # a transaction in progress. If we do, stick it in the pending_pdus
         # table and we'll get back to it later.
 
-        destinations = set([
-            d for d in pdu.destinations
-            if d != self.server_name
-        ])
+        destinations = set(destinations)
+        destinations.discard(self.server_name)
 
         logger.debug("Sending to: %s", str(destinations))
 
@@ -728,8 +731,14 @@ class _TransactionQueue(object):
                 (pdu, deferred, order)
             )
 
+            def eb(failure):
+                if not deferred.called:
+                    deferred.errback(failure)
+                else:
+                    logger.warn("Failed to send pdu", failure)
+
             with PreserveLoggingContext():
-                self._attempt_new_transaction(destination)
+                self._attempt_new_transaction(destination).addErrback(eb)
 
             deferreds.append(deferred)
 
@@ -739,6 +748,9 @@ class _TransactionQueue(object):
     def enqueue_edu(self, edu):
         destination = edu.destination
 
+        if destination == self.server_name:
+            return
+
         deferred = defer.Deferred()
         self.pending_edus_by_dest.setdefault(destination, []).append(
             (edu, deferred)
@@ -748,7 +760,7 @@ class _TransactionQueue(object):
             if not deferred.called:
                 deferred.errback(failure)
             else:
-                logger.exception("Failed to send edu", failure)
+                logger.warn("Failed to send edu", failure)
 
         with PreserveLoggingContext():
             self._attempt_new_transaction(destination).addErrback(eb)
@@ -770,10 +782,33 @@ class _TransactionQueue(object):
     @defer.inlineCallbacks
     @log_function
     def _attempt_new_transaction(self, destination):
+
+        (retry_last_ts, retry_interval) = (0, 0)
+        retry_timings = yield self.store.get_destination_retry_timings(
+            destination
+        )
+        if retry_timings:
+            (retry_last_ts, retry_interval) = (
+                retry_timings.retry_last_ts, retry_timings.retry_interval
+            )
+            if retry_last_ts + retry_interval > int(self._clock.time_msec()):
+                logger.info(
+                    "TX [%s] not ready for retry yet - "
+                    "dropping transaction for now",
+                    destination,
+                )
+                return
+            else:
+                logger.info("TX [%s] is ready for retry", destination)
+
         if destination in self.pending_transactions:
+            # XXX: pending_transactions can get stuck on by a never-ending
+            # request at which point pending_pdus_by_dest just keeps growing.
+            # we need application-layer timeouts of some flavour of these
+            # requests
             return
 
-        #  list of (pending_pdu, deferred, order)
+        # list of (pending_pdu, deferred, order)
         pending_pdus = self.pending_pdus_by_dest.pop(destination, [])
         pending_edus = self.pending_edus_by_dest.pop(destination, [])
         pending_failures = self.pending_failures_by_dest.pop(destination, [])
@@ -781,7 +816,14 @@ class _TransactionQueue(object):
         if not pending_pdus and not pending_edus and not pending_failures:
             return
 
-        logger.debug("TX [%s] Attempting new transaction", destination)
+        logger.debug(
+            "TX [%s] Attempting new transaction "
+            "(pdus: %d, edus: %d, failures: %d)",
+            destination,
+            len(pending_pdus),
+            len(pending_edus),
+            len(pending_failures)
+        )
 
         # Sort based on the order field
         pending_pdus.sort(key=lambda t: t[2])
@@ -814,7 +856,11 @@ class _TransactionQueue(object):
             yield self.transaction_actions.prepare_to_send(transaction)
 
             logger.debug("TX [%s] Persisted transaction", destination)
-            logger.debug("TX [%s] Sending transaction...", destination)
+            logger.info(
+                "TX [%s] Sending transaction [%s]",
+                destination,
+                transaction.transaction_id,
+            )
 
             # Actually send the transaction
 
@@ -835,6 +881,8 @@ class _TransactionQueue(object):
                 transaction, json_data_cb
             )
 
+            logger.info("TX [%s] got %d response", destination, code)
+
             logger.debug("TX [%s] Sent transaction", destination)
             logger.debug("TX [%s] Marking as delivered...", destination)
 
@@ -847,8 +895,14 @@ class _TransactionQueue(object):
 
             for deferred in deferreds:
                 if code == 200:
+                    if retry_last_ts:
+                        # this host is alive! reset retry schedule
+                        yield self.store.set_destination_retry_timings(
+                            destination, 0, 0
+                        )
                     deferred.callback(None)
                 else:
+                    self.set_retrying(destination, retry_interval)
                     deferred.errback(RuntimeError("Got status %d" % code))
 
                 # Ensures we don't continue until all callbacks on that
@@ -861,11 +915,15 @@ class _TransactionQueue(object):
             logger.debug("TX [%s] Yielded to callbacks", destination)
 
         except Exception as e:
-            logger.error("TX Problem in _attempt_transaction")
-
             # We capture this here as there as nothing actually listens
             # for this finishing functions deferred.
-            logger.exception(e)
+            logger.warn(
+                "TX [%s] Problem in _attempt_transaction: %s",
+                destination,
+                e,
+            )
+
+            self.set_retrying(destination, retry_interval)
 
             for deferred in deferreds:
                 if not deferred.called:
@@ -877,3 +935,22 @@ class _TransactionQueue(object):
 
             # Check to see if there is anything else to send.
             self._attempt_new_transaction(destination)
+
+    @defer.inlineCallbacks
+    def set_retrying(self, destination, retry_interval):
+        # track that this destination is having problems and we should
+        # give it a chance to recover before trying it again
+
+        if retry_interval:
+            retry_interval *= 2
+            # plateau at hourly retries for now
+            if retry_interval >= 60 * 60 * 1000:
+                retry_interval = 60 * 60 * 1000
+        else:
+            retry_interval = 2000  # try again at first after 2 seconds
+
+        yield self.store.set_destination_retry_timings(
+            destination,
+            int(self._clock.time_msec()),
+            retry_interval
+        )
diff --git a/synapse/federation/transport.py b/synapse/federation/transport.py
index 8d86152085..0f11c6d491 100644
--- a/synapse/federation/transport.py
+++ b/synapse/federation/transport.py
@@ -155,7 +155,7 @@ class TransportLayer(object):
     @defer.inlineCallbacks
     @log_function
     def send_transaction(self, transaction, json_data_callback=None):
-        """ Sends the given Transaction to it's destination
+        """ Sends the given Transaction to its destination
 
         Args:
             transaction (Transaction)
diff --git a/synapse/handlers/_base.py b/synapse/handlers/_base.py
index 15adc9dc2c..97ebd98917 100644
--- a/synapse/handlers/_base.py
+++ b/synapse/handlers/_base.py
@@ -15,11 +15,10 @@
 
 from twisted.internet import defer
 
-from synapse.api.errors import LimitExceededError
+from synapse.api.errors import LimitExceededError, SynapseError
 from synapse.util.async import run_on_reactor
 from synapse.crypto.event_signing import add_hashes_and_signatures
-from synapse.api.events.room import RoomMemberEvent
-from synapse.api.constants import Membership
+from synapse.api.constants import Membership, EventTypes
 
 import logging
 
@@ -31,10 +30,8 @@ class BaseHandler(object):
 
     def __init__(self, hs):
         self.store = hs.get_datastore()
-        self.event_factory = hs.get_event_factory()
         self.auth = hs.get_auth()
         self.notifier = hs.get_notifier()
-        self.room_lock = hs.get_room_lock_manager()
         self.state_handler = hs.get_state_handler()
         self.distributor = hs.get_distributor()
         self.ratelimiter = hs.get_ratelimiter()
@@ -44,6 +41,8 @@ class BaseHandler(object):
         self.signing_key = hs.config.signing_key[0]
         self.server_name = hs.hostname
 
+        self.event_builder_factory = hs.get_event_builder_factory()
+
     def ratelimit(self, user_id):
         time_now = self.clock.time()
         allowed, time_allowed = self.ratelimiter.send_message(
@@ -57,62 +56,95 @@ class BaseHandler(object):
             )
 
     @defer.inlineCallbacks
-    def _on_new_room_event(self, event, snapshot, extra_destinations=[],
-                           extra_users=[], suppress_auth=False,
-                           do_invite_host=None):
+    def _create_new_client_event(self, builder):
         yield run_on_reactor()
 
-        snapshot.fill_out_prev_events(event)
+        latest_ret = yield self.store.get_latest_events_in_room(
+            builder.room_id,
+        )
+
+        if latest_ret:
+            depth = max([d for _, _, d in latest_ret]) + 1
+        else:
+            depth = 1
+
+        prev_events = [(e, h) for e, h, _ in latest_ret]
+
+        builder.prev_events = prev_events
+        builder.depth = depth
 
-        yield self.state_handler.annotate_event_with_state(event)
+        state_handler = self.state_handler
 
-        yield self.auth.add_auth_events(event)
+        context = yield state_handler.compute_event_context(builder)
 
-        logger.debug("Signing event...")
+        if builder.is_state():
+            builder.prev_state = context.prev_state_events
+
+        yield self.auth.add_auth_events(builder, context)
 
         add_hashes_and_signatures(
-            event, self.server_name, self.signing_key
+            builder, self.server_name, self.signing_key
+        )
+
+        event = builder.build()
+
+        logger.debug(
+            "Created event %s with auth_events: %s, current state: %s",
+            event.event_id, context.auth_events, context.current_state,
+        )
+
+        defer.returnValue(
+            (event, context,)
         )
 
-        logger.debug("Signed event.")
+    @defer.inlineCallbacks
+    def handle_new_client_event(self, event, context, extra_destinations=[],
+                                extra_users=[], suppress_auth=False):
+        yield run_on_reactor()
+
+        # We now need to go and hit out to wherever we need to hit out to.
 
         if not suppress_auth:
-            logger.debug("Authing...")
-            self.auth.check(event, auth_events=event.old_state_events)
-            logger.debug("Authed")
-        else:
-            logger.debug("Suppressed auth.")
+            self.auth.check(event, auth_events=context.auth_events)
 
-        if do_invite_host:
-            federation_handler = self.hs.get_handlers().federation_handler
-            invite_event = yield federation_handler.send_invite(
-                do_invite_host,
-                event
-            )
+        yield self.store.persist_event(event, context=context)
 
-            # FIXME: We need to check if the remote changed anything else
-            event.signatures = invite_event.signatures
+        federation_handler = self.hs.get_handlers().federation_handler
 
-        yield self.store.persist_event(event)
+        if event.type == EventTypes.Member:
+            if event.content["membership"] == Membership.INVITE:
+                invitee = self.hs.parse_userid(event.state_key)
+                if not self.hs.is_mine(invitee):
+                    # TODO: Can we add signature from remote server in a nicer
+                    # way? If we have been invited by a remote server, we need
+                    # to get them to sign the event.
+                    returned_invite = yield federation_handler.send_invite(
+                        invitee.domain,
+                        event,
+                    )
+
+                    # TODO: Make sure the signatures actually are correct.
+                    event.signatures.update(
+                        returned_invite.signatures
+                    )
 
         destinations = set(extra_destinations)
-        # Send a PDU to all hosts who have joined the room.
-
-        for k, s in event.state_events.items():
+        for k, s in context.current_state.items():
             try:
-                if k[0] == RoomMemberEvent.TYPE:
+                if k[0] == EventTypes.Member:
                     if s.content["membership"] == Membership.JOIN:
                         destinations.add(
                             self.hs.parse_userid(s.state_key).domain
                         )
-            except:
+            except SynapseError:
                 logger.warn(
                     "Failed to get destination from event %s", s.event_id
                 )
 
-        event.destinations = list(destinations)
-
         yield self.notifier.on_new_room_event(event, extra_users=extra_users)
 
-        federation_handler = self.hs.get_handlers().federation_handler
-        yield federation_handler.handle_new_event(event, snapshot)
+        yield federation_handler.handle_new_event(
+            event,
+            None,
+            destinations=destinations,
+        )
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 3b37e49e6f..66d3b533d9 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -18,7 +18,7 @@ from twisted.internet import defer
 from ._base import BaseHandler
 
 from synapse.api.errors import SynapseError, Codes, CodeMessageException
-from synapse.api.events.room import RoomAliasesEvent
+from synapse.api.constants import EventTypes
 
 import logging
 
@@ -40,7 +40,7 @@ class DirectoryHandler(BaseHandler):
 
         # TODO(erikj): Do auth.
 
-        if not room_alias.is_mine:
+        if not self.hs.is_mine(room_alias):
             raise SynapseError(400, "Room alias must be local")
             # TODO(erikj): Change this.
 
@@ -64,7 +64,7 @@ class DirectoryHandler(BaseHandler):
     def delete_association(self, user_id, room_alias):
         # TODO Check if server admin
 
-        if not room_alias.is_mine:
+        if not self.hs.is_mine(room_alias):
             raise SynapseError(400, "Room alias must be local")
 
         room_id = yield self.store.delete_room_alias(room_alias)
@@ -75,7 +75,7 @@ class DirectoryHandler(BaseHandler):
     @defer.inlineCallbacks
     def get_association(self, room_alias):
         room_id = None
-        if room_alias.is_mine:
+        if self.hs.is_mine(room_alias):
             result = yield self.store.get_association_from_room_alias(
                 room_alias
             )
@@ -123,7 +123,7 @@ class DirectoryHandler(BaseHandler):
     @defer.inlineCallbacks
     def on_directory_query(self, args):
         room_alias = self.hs.parse_roomalias(args["room_alias"])
-        if not room_alias.is_mine:
+        if not self.hs.is_mine(room_alias):
             raise SynapseError(
                 400, "Room Alias is not hosted on this Home Server"
             )
@@ -148,16 +148,11 @@ class DirectoryHandler(BaseHandler):
     def send_room_alias_update_event(self, user_id, room_id):
         aliases = yield self.store.get_aliases_for_room(room_id)
 
-        event = self.event_factory.create_event(
-            etype=RoomAliasesEvent.TYPE,
-            state_key=self.hs.hostname,
-            room_id=room_id,
-            user_id=user_id,
-            content={"aliases": aliases},
-        )
-
-        snapshot = yield self.store.snapshot_room(event)
-
-        yield self._on_new_room_event(
-            event, snapshot, extra_users=[user_id], suppress_auth=True
-        )
+        msg_handler = self.hs.get_handlers().message_handler
+        yield msg_handler.create_and_send_event({
+            "type": EventTypes.Aliases,
+            "state_key": self.hs.hostname,
+            "room_id": room_id,
+            "sender": user_id,
+            "content": {"aliases": aliases},
+        })
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 925eb5376e..4aec3563ac 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -17,12 +17,11 @@
 
 from ._base import BaseHandler
 
-from synapse.api.events.utils import prune_event
+from synapse.events.utils import prune_event
 from synapse.api.errors import (
     AuthError, FederationError, SynapseError, StoreError,
 )
-from synapse.api.events.room import RoomMemberEvent, RoomCreateEvent
-from synapse.api.constants import Membership
+from synapse.api.constants import EventTypes, Membership
 from synapse.util.logutils import log_function
 from synapse.util.async import run_on_reactor
 from synapse.crypto.event_signing import (
@@ -76,7 +75,7 @@ class FederationHandler(BaseHandler):
 
     @log_function
     @defer.inlineCallbacks
-    def handle_new_event(self, event, snapshot):
+    def handle_new_event(self, event, snapshot, destinations):
         """ Takes in an event from the client to server side, that has already
         been authed and handled by the state module, and sends it to any
         remote home servers that may be interested.
@@ -92,12 +91,7 @@ class FederationHandler(BaseHandler):
 
         yield run_on_reactor()
 
-        pdu = event
-
-        if not hasattr(pdu, "destinations") or not pdu.destinations:
-            pdu.destinations = []
-
-        yield self.replication_layer.send_pdu(pdu)
+        yield self.replication_layer.send_pdu(event, destinations)
 
     @log_function
     @defer.inlineCallbacks
@@ -140,7 +134,7 @@ class FederationHandler(BaseHandler):
         if not check_event_content_hash(event):
             logger.warn(
                 "Event content has been tampered, redacting %s, %s",
-                event.event_id, encode_canonical_json(event.get_full_dict())
+                event.event_id, encode_canonical_json(event.get_dict())
             )
             event = redacted_event
 
@@ -153,7 +147,7 @@ class FederationHandler(BaseHandler):
             event.room_id,
             self.server_name
         )
-        if not is_in_room and not event.outlier:
+        if not is_in_room and not event.internal_metadata.outlier:
             logger.debug("Got event for room we're not in.")
 
             replication_layer = self.replication_layer
@@ -164,7 +158,7 @@ class FederationHandler(BaseHandler):
             )
 
             for e in auth_chain:
-                e.outlier = True
+                e.internal_metadata.outlier = True
                 try:
                     yield self._handle_new_event(e, fetch_missing=False)
                 except:
@@ -184,7 +178,7 @@ class FederationHandler(BaseHandler):
 
         if state:
             for e in state:
-                e.outlier = True
+                e.internal_metadata.outlier = True
                 try:
                     yield self._handle_new_event(e)
                 except:
@@ -208,6 +202,13 @@ class FederationHandler(BaseHandler):
                 affected=event.event_id,
             )
 
+        # if we're receiving valid events from an origin,
+        # it's probably a good idea to mark it as not in retry-state
+        # for sending (although this is a bit of a leap)
+        retry_timings = yield self.store.get_destination_retry_timings(origin)
+        if (retry_timings and retry_timings.retry_last_ts):
+            self.store.set_destination_retry_timings(origin, 0, 0)
+
         room = yield self.store.get_room(event.room_id)
 
         if not room:
@@ -222,7 +223,7 @@ class FederationHandler(BaseHandler):
 
         if not backfilled:
             extra_users = []
-            if event.type == RoomMemberEvent.TYPE:
+            if event.type == EventTypes.Member:
                 target_user_id = event.state_key
                 target_user = self.hs.parse_userid(target_user_id)
                 extra_users.append(target_user)
@@ -231,7 +232,7 @@ class FederationHandler(BaseHandler):
                 event, extra_users=extra_users
             )
 
-        if event.type == RoomMemberEvent.TYPE:
+        if event.type == EventTypes.Member:
             if event.membership == Membership.JOIN:
                 user = self.hs.parse_userid(event.state_key)
                 yield self.distributor.fire(
@@ -258,11 +259,15 @@ class FederationHandler(BaseHandler):
             event = pdu
 
             # FIXME (erikj): Not sure this actually works :/
-            yield self.state_handler.annotate_event_with_state(event)
+            context = yield self.state_handler.compute_event_context(event)
 
-            events.append(event)
+            events.append((event, context))
 
-            yield self.store.persist_event(event, backfilled=True)
+            yield self.store.persist_event(
+                event,
+                context=context,
+                backfilled=True
+            )
 
         defer.returnValue(events)
 
@@ -279,8 +284,6 @@ class FederationHandler(BaseHandler):
             pdu=event
         )
 
-
-
         defer.returnValue(pdu)
 
     @defer.inlineCallbacks
@@ -325,42 +328,55 @@ class FederationHandler(BaseHandler):
         event = pdu
 
         # We should assert some things.
-        assert(event.type == RoomMemberEvent.TYPE)
+        # FIXME: Do this in a nicer way
+        assert(event.type == EventTypes.Member)
         assert(event.user_id == joinee)
         assert(event.state_key == joinee)
         assert(event.room_id == room_id)
 
-        event.outlier = False
+        event.internal_metadata.outlier = False
 
         self.room_queues[room_id] = []
 
+        builder = self.event_builder_factory.new(
+            event.get_pdu_json()
+        )
+
+        handled_events = set()
+
         try:
-            event.event_id = self.event_factory.create_event_id()
-            event.origin = self.hs.hostname
-            event.content = content
+            builder.event_id = self.event_builder_factory.create_event_id()
+            builder.origin = self.hs.hostname
+            builder.content = content
 
             if not hasattr(event, "signatures"):
-                event.signatures = {}
+                builder.signatures = {}
 
             add_hashes_and_signatures(
-                event,
+                builder,
                 self.hs.hostname,
                 self.hs.config.signing_key[0],
             )
 
+            new_event = builder.build()
+
             ret = yield self.replication_layer.send_join(
                 target_host,
-                event
+                new_event
             )
 
             state = ret["state"]
             auth_chain = ret["auth_chain"]
             auth_chain.sort(key=lambda e: e.depth)
 
+            handled_events.update([s.event_id for s in state])
+            handled_events.update([a.event_id for a in auth_chain])
+            handled_events.add(new_event.event_id)
+
             logger.debug("do_invite_join auth_chain: %s", auth_chain)
             logger.debug("do_invite_join state: %s", state)
 
-            logger.debug("do_invite_join event: %s", event)
+            logger.debug("do_invite_join event: %s", new_event)
 
             try:
                 yield self.store.store_room(
@@ -373,7 +389,7 @@ class FederationHandler(BaseHandler):
                 pass
 
             for e in auth_chain:
-                e.outlier = True
+                e.internal_metadata.outlier = True
                 try:
                     yield self._handle_new_event(e, fetch_missing=False)
                 except:
@@ -384,7 +400,7 @@ class FederationHandler(BaseHandler):
 
             for e in state:
                 # FIXME: Auth these.
-                e.outlier = True
+                e.internal_metadata.outlier = True
                 try:
                     yield self._handle_new_event(
                         e,
@@ -397,13 +413,13 @@ class FederationHandler(BaseHandler):
                     )
 
             yield self._handle_new_event(
-                event,
+                new_event,
                 state=state,
                 current_state=state,
             )
 
             yield self.notifier.on_new_room_event(
-                event, extra_users=[joinee]
+                new_event, extra_users=[joinee]
             )
 
             logger.debug("Finished joining %s to %s", joinee, room_id)
@@ -412,6 +428,9 @@ class FederationHandler(BaseHandler):
             del self.room_queues[room_id]
 
             for p, origin in room_queue:
+                if p.event_id in handled_events:
+                    continue
+
                 try:
                     self.on_receive_pdu(origin, p, backfilled=False)
                 except:
@@ -421,25 +440,24 @@ class FederationHandler(BaseHandler):
 
     @defer.inlineCallbacks
     @log_function
-    def on_make_join_request(self, context, user_id):
+    def on_make_join_request(self, room_id, user_id):
         """ We've received a /make_join/ request, so we create a partial
         join event for the room and return that. We don *not* persist or
         process it until the other server has signed it and sent it back.
         """
-        event = self.event_factory.create_event(
-            etype=RoomMemberEvent.TYPE,
-            content={"membership": Membership.JOIN},
-            room_id=context,
-            user_id=user_id,
-            state_key=user_id,
-        )
+        builder = self.event_builder_factory.new({
+            "type": EventTypes.Member,
+            "content": {"membership": Membership.JOIN},
+            "room_id": room_id,
+            "sender": user_id,
+            "state_key": user_id,
+        })
 
-        snapshot = yield self.store.snapshot_room(event)
-        snapshot.fill_out_prev_events(event)
+        event, context = yield self._create_new_client_event(
+            builder=builder,
+        )
 
-        yield self.state_handler.annotate_event_with_state(event)
-        yield self.auth.add_auth_events(event)
-        self.auth.check(event, auth_events=event.old_state_events)
+        self.auth.check(event, auth_events=context.auth_events)
 
         pdu = event
 
@@ -453,12 +471,24 @@ class FederationHandler(BaseHandler):
         """
         event = pdu
 
-        event.outlier = False
+        logger.debug(
+            "on_send_join_request: Got event: %s, signatures: %s",
+            event.event_id,
+            event.signatures,
+        )
 
-        yield self._handle_new_event(event)
+        event.internal_metadata.outlier = False
+
+        context = yield self._handle_new_event(event)
+
+        logger.debug(
+            "on_send_join_request: After _handle_new_event: %s, sigs: %s",
+            event.event_id,
+            event.signatures,
+        )
 
         extra_users = []
-        if event.type == RoomMemberEvent.TYPE:
+        if event.type == EventTypes.Member:
             target_user_id = event.state_key
             target_user = self.hs.parse_userid(target_user_id)
             extra_users.append(target_user)
@@ -467,7 +497,7 @@ class FederationHandler(BaseHandler):
             event, extra_users=extra_users
         )
 
-        if event.type == RoomMemberEvent.TYPE:
+        if event.type == EventTypes.Member:
             if event.content["membership"] == Membership.JOIN:
                 user = self.hs.parse_userid(event.state_key)
                 yield self.distributor.fire(
@@ -478,9 +508,9 @@ class FederationHandler(BaseHandler):
 
         destinations = set()
 
-        for k, s in event.state_events.items():
+        for k, s in context.current_state.items():
             try:
-                if k[0] == RoomMemberEvent.TYPE:
+                if k[0] == EventTypes.Member:
                     if s.content["membership"] == Membership.JOIN:
                         destinations.add(
                             self.hs.parse_userid(s.state_key).domain
@@ -490,14 +520,18 @@ class FederationHandler(BaseHandler):
                     "Failed to get destination from event %s", s.event_id
                 )
 
-        new_pdu.destinations = list(destinations)
+        logger.debug(
+            "on_send_join_request: Sending event: %s, signatures: %s",
+            event.event_id,
+            event.signatures,
+        )
 
-        yield self.replication_layer.send_pdu(new_pdu)
+        yield self.replication_layer.send_pdu(new_pdu, destinations)
 
         auth_chain = yield self.store.get_auth_chain(event.event_id)
 
         defer.returnValue({
-            "state": event.state_events.values(),
+            "state": context.current_state.values(),
             "auth_chain": auth_chain,
         })
 
@@ -509,7 +543,7 @@ class FederationHandler(BaseHandler):
         """
         event = pdu
 
-        event.outlier = True
+        event.internal_metadata.outlier = True
 
         event.signatures.update(
             compute_event_signature(
@@ -519,10 +553,11 @@ class FederationHandler(BaseHandler):
             )
         )
 
-        yield self.state_handler.annotate_event_with_state(event)
+        context = yield self.state_handler.compute_event_context(event)
 
         yield self.store.persist_event(
             event,
+            context=context,
             backfilled=False,
         )
 
@@ -552,13 +587,13 @@ class FederationHandler(BaseHandler):
             }
 
             event = yield self.store.get_event(event_id)
-            if hasattr(event, "state_key"):
+            if event and event.is_state():
                 # Get previous state
-                if hasattr(event, "replaces_state") and event.replaces_state:
-                    prev_event = yield self.store.get_event(
-                        event.replaces_state
-                    )
-                    results[(event.type, event.state_key)] = prev_event
+                if "replaces_state" in event.unsigned:
+                    prev_id = event.unsigned["replaces_state"]
+                    if prev_id != event.event_id:
+                        prev_event = yield self.store.get_event(prev_id)
+                        results[(event.type, event.state_key)] = prev_event
                 else:
                     del results[(event.type, event.state_key)]
 
@@ -644,74 +679,78 @@ class FederationHandler(BaseHandler):
     @defer.inlineCallbacks
     def _handle_new_event(self, event, state=None, backfilled=False,
                           current_state=None, fetch_missing=True):
-        is_new_state = yield self.state_handler.annotate_event_with_state(
-            event,
-            old_state=state
-        )
 
-        if event.old_state_events:
-            known_ids = set(
-                [s.event_id for s in event.old_state_events.values()]
-            )
-            for e_id, _ in event.auth_events:
-                if e_id not in known_ids:
-                    e = yield self.store.get_event(
-                        e_id,
-                        allow_none=True,
-                    )
+        logger.debug(
+            "_handle_new_event: Before annotate: %s, sigs: %s",
+            event.event_id, event.signatures,
+        )
 
-                    if not e:
-                        # TODO: Do some conflict res to make sure that we're
-                        # not the ones who are wrong.
-                        logger.info(
-                            "Rejecting %s as %s not in %s",
-                            event.event_id, e_id, known_ids,
-                        )
-                        raise AuthError(403, "Auth events are stale")
+        context = yield self.state_handler.compute_event_context(
+            event, old_state=state
+        )
 
-            auth_events = event.old_state_events
-        else:
-            # We need to get the auth events from somewhere.
+        logger.debug(
+            "_handle_new_event: Before auth fetch: %s, sigs: %s",
+            event.event_id, event.signatures,
+        )
 
-            # TODO: Don't just hit the DBs?
+        is_new_state = not event.internal_metadata.is_outlier()
 
-            auth_events = {}
-            for e_id, _ in event.auth_events:
+        known_ids = set(
+            [s.event_id for s in context.auth_events.values()]
+        )
+        for e_id, _ in event.auth_events:
+            if e_id not in known_ids:
                 e = yield self.store.get_event(
-                    e_id,
-                    allow_none=True,
+                    e_id, allow_none=True,
                 )
 
                 if not e:
-                    e = yield self.replication_layer.get_pdu(
-                        event.origin, e_id, outlier=True
+                    # TODO: Do some conflict res to make sure that we're
+                    # not the ones who are wrong.
+                    logger.info(
+                        "Rejecting %s as %s not in db or %s",
+                        event.event_id, e_id, known_ids,
                     )
+                    # FIXME: How does raising AuthError work with federation?
+                    raise AuthError(403, "Auth events are stale")
 
-                    if e and fetch_missing:
-                        try:
-                            yield self.on_receive_pdu(event.origin, e, False)
-                        except:
-                            logger.exception(
-                                "Failed to parse auth event %s",
-                                e_id,
-                            )
+                context.auth_events[(e.type, e.state_key)] = e
 
-                if not e:
-                    logger.warn("Can't find auth event %s.", e_id)
+        logger.debug(
+            "_handle_new_event: Before hack: %s, sigs: %s",
+            event.event_id, event.signatures,
+        )
+
+        if event.type == EventTypes.Member and not event.auth_events:
+            if len(event.prev_events) == 1:
+                c = yield self.store.get_event(event.prev_events[0][0])
+                if c.type == EventTypes.Create:
+                    context.auth_events[(c.type, c.state_key)] = c
 
-                auth_events[(e.type, e.state_key)] = e
+        logger.debug(
+            "_handle_new_event: Before auth check: %s, sigs: %s",
+            event.event_id, event.signatures,
+        )
 
-            if event.type == RoomMemberEvent.TYPE and not event.auth_events:
-                if len(event.prev_events) == 1:
-                    c = yield self.store.get_event(event.prev_events[0][0])
-                    if c.type == RoomCreateEvent.TYPE:
-                        auth_events[(c.type, c.state_key)] = c
+        self.auth.check(event, auth_events=context.auth_events)
 
-        self.auth.check(event, auth_events=auth_events)
+        logger.debug(
+            "_handle_new_event: Before persist_event: %s, sigs: %s",
+            event.event_id, event.signatures,
+        )
 
         yield self.store.persist_event(
             event,
+            context=context,
             backfilled=backfilled,
             is_new_state=(is_new_state and not backfilled),
             current_state=current_state,
         )
+
+        logger.debug(
+            "_handle_new_event: After persist_event: %s, sigs: %s",
+            event.event_id, event.signatures,
+        )
+
+        defer.returnValue(context)
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 42dc4d46f3..49c0e98113 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -15,10 +15,11 @@
 
 from twisted.internet import defer
 
-from synapse.api.constants import Membership
+from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import RoomError
 from synapse.streams.config import PaginationConfig
-from synapse.util.logcontext import PreserveLoggingContext
+from synapse.events.validator import EventValidator
+
 from ._base import BaseHandler
 
 import logging
@@ -32,7 +33,7 @@ class MessageHandler(BaseHandler):
         super(MessageHandler, self).__init__(hs)
         self.hs = hs
         self.clock = hs.get_clock()
-        self.event_factory = hs.get_event_factory()
+        self.validator = EventValidator()
 
     @defer.inlineCallbacks
     def get_message(self, msg_id=None, room_id=None, sender_id=None,
@@ -64,35 +65,6 @@ class MessageHandler(BaseHandler):
         defer.returnValue(None)
 
     @defer.inlineCallbacks
-    def send_message(self, event=None, suppress_auth=False):
-        """ Send a message.
-
-        Args:
-            event : The message event to store.
-            suppress_auth (bool) : True to suppress auth for this message. This
-            is primarily so the home server can inject messages into rooms at
-            will.
-        Raises:
-            SynapseError if something went wrong.
-        """
-
-        self.ratelimit(event.user_id)
-        # TODO(paul): Why does 'event' not have a 'user' object?
-        user = self.hs.parse_userid(event.user_id)
-        assert user.is_mine, "User must be our own: %s" % (user,)
-
-        snapshot = yield self.store.snapshot_room(event)
-
-        yield self._on_new_room_event(
-            event, snapshot, suppress_auth=suppress_auth
-        )
-
-        with PreserveLoggingContext():
-            self.hs.get_handlers().presence_handler.bump_presence_active_time(
-                user
-            )
-
-    @defer.inlineCallbacks
     def get_messages(self, user_id=None, room_id=None, pagin_config=None,
                      feedback=False):
         """Get messages in a room.
@@ -134,19 +106,53 @@ class MessageHandler(BaseHandler):
         defer.returnValue(chunk)
 
     @defer.inlineCallbacks
-    def store_room_data(self, event=None):
-        """ Stores data for a room.
+    def create_and_send_event(self, event_dict):
+        """ Given a dict from a client, create and handle a new event.
+
+        Creates an FrozenEvent object, filling out auth_events, prev_events,
+        etc.
+
+        Adds display names to Join membership events.
+
+        Persists and notifies local clients and federation.
 
         Args:
-            event : The room path event
-            stamp_event (bool) : True to stamp event content with server keys.
-        Raises:
-            SynapseError if something went wrong.
+            event_dict (dict): An entire event
         """
+        builder = self.event_builder_factory.new(event_dict)
 
-        snapshot = yield self.store.snapshot_room(event)
+        self.validator.validate_new(builder)
 
-        yield self._on_new_room_event(event, snapshot)
+        self.ratelimit(builder.user_id)
+        # TODO(paul): Why does 'event' not have a 'user' object?
+        user = self.hs.parse_userid(builder.user_id)
+        assert self.hs.is_mine(user), "User must be our own: %s" % (user,)
+
+        if builder.type == EventTypes.Member:
+            membership = builder.content.get("membership", None)
+            if membership == Membership.JOIN:
+                joinee = self.hs.parse_userid(builder.state_key)
+                # If event doesn't include a display name, add one.
+                yield self.distributor.fire(
+                    "collect_presencelike_data",
+                    joinee,
+                    builder.content
+                )
+
+        event, context = yield self._create_new_client_event(
+            builder=builder,
+        )
+
+        if event.type == EventTypes.Member:
+            member_handler = self.hs.get_handlers().room_member_handler
+            yield member_handler.change_membership(event, context)
+        else:
+            yield self.handle_new_client_event(
+                event=event,
+                context=context,
+            )
+
+        defer.returnValue(event)
 
     @defer.inlineCallbacks
     def get_room_data(self, user_id=None, room_id=None,
@@ -181,13 +187,6 @@ class MessageHandler(BaseHandler):
         defer.returnValue(None)
 
     @defer.inlineCallbacks
-    def send_feedback(self, event):
-        snapshot = yield self.store.snapshot_room(event)
-
-        # store message in db
-        yield self._on_new_room_event(event, snapshot)
-
-    @defer.inlineCallbacks
     def get_state_events(self, user_id, room_id):
         """Retrieve all state events for a given room.
 
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 815d40f166..f3abfecdee 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -147,7 +147,7 @@ class PresenceHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def is_presence_visible(self, observer_user, observed_user):
-        assert(observed_user.is_mine)
+        assert(self.hs.is_mine(observed_user))
 
         if observer_user == observed_user:
             defer.returnValue(True)
@@ -165,7 +165,7 @@ class PresenceHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def get_state(self, target_user, auth_user, as_event=False):
-        if target_user.is_mine:
+        if self.hs.is_mine(target_user):
             visible = yield self.is_presence_visible(
                 observer_user=auth_user,
                 observed_user=target_user
@@ -212,7 +212,7 @@ class PresenceHandler(BaseHandler):
         # TODO (erikj): Turn this back on. Why did we end up sending EDUs
         # everywhere?
 
-        if not target_user.is_mine:
+        if not self.hs.is_mine(target_user):
             raise SynapseError(400, "User is not hosted on this Home Server")
 
         if target_user != auth_user:
@@ -291,7 +291,7 @@ class PresenceHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def user_joined_room(self, user, room_id):
-        if user.is_mine:
+        if self.hs.is_mine(user):
             statuscache = self._get_or_make_usercache(user)
 
             # No actual update but we need to bump the serial anyway for the
@@ -309,7 +309,7 @@ class PresenceHandler(BaseHandler):
         rm_handler = self.homeserver.get_handlers().room_member_handler
         curr_users = yield rm_handler.get_room_members(room_id)
 
-        for local_user in [c for c in curr_users if c.is_mine]:
+        for local_user in [c for c in curr_users if self.hs.is_mine(c)]:
             self.push_update_to_local_and_remote(
                 observed_user=local_user,
                 users_to_push=[user],
@@ -318,14 +318,14 @@ class PresenceHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def send_invite(self, observer_user, observed_user):
-        if not observer_user.is_mine:
+        if not self.hs.is_mine(observer_user):
             raise SynapseError(400, "User is not hosted on this Home Server")
 
         yield self.store.add_presence_list_pending(
             observer_user.localpart, observed_user.to_string()
         )
 
-        if observed_user.is_mine:
+        if self.hs.is_mine(observed_user):
             yield self.invite_presence(observed_user, observer_user)
         else:
             yield self.federation.send_edu(
@@ -339,7 +339,7 @@ class PresenceHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def _should_accept_invite(self, observed_user, observer_user):
-        if not observed_user.is_mine:
+        if not self.hs.is_mine(observed_user):
             defer.returnValue(False)
 
         row = yield self.store.has_presence_state(observed_user.localpart)
@@ -359,7 +359,7 @@ class PresenceHandler(BaseHandler):
                 observed_user.localpart, observer_user.to_string()
             )
 
-        if observer_user.is_mine:
+        if self.hs.is_mine(observer_user):
             if accept:
                 yield self.accept_presence(observed_user, observer_user)
             else:
@@ -396,7 +396,7 @@ class PresenceHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def drop(self, observed_user, observer_user):
-        if not observer_user.is_mine:
+        if not self.hs.is_mine(observer_user):
             raise SynapseError(400, "User is not hosted on this Home Server")
 
         yield self.store.del_presence_list(
@@ -410,7 +410,7 @@ class PresenceHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def get_presence_list(self, observer_user, accepted=None):
-        if not observer_user.is_mine:
+        if not self.hs.is_mine(observer_user):
             raise SynapseError(400, "User is not hosted on this Home Server")
 
         presence = yield self.store.get_presence_list(
@@ -465,7 +465,7 @@ class PresenceHandler(BaseHandler):
         )
 
         for target_user in target_users:
-            if target_user.is_mine:
+            if self.hs.is_mine(target_user):
                 self._start_polling_local(user, target_user)
 
                 # We want to tell the person that just came online
@@ -477,7 +477,7 @@ class PresenceHandler(BaseHandler):
                 )
 
         deferreds = []
-        remote_users = [u for u in target_users if not u.is_mine]
+        remote_users = [u for u in target_users if not self.hs.is_mine(u)]
         remoteusers_by_domain = partition(remote_users, lambda u: u.domain)
         # Only poll for people in our get_presence_list
         for domain in remoteusers_by_domain:
@@ -520,7 +520,7 @@ class PresenceHandler(BaseHandler):
     def stop_polling_presence(self, user, target_user=None):
         logger.debug("Stop polling for presence from %s", user)
 
-        if not target_user or target_user.is_mine:
+        if not target_user or self.hs.is_mine(target_user):
             self._stop_polling_local(user, target_user=target_user)
 
         deferreds = []
@@ -579,7 +579,7 @@ class PresenceHandler(BaseHandler):
     @defer.inlineCallbacks
     @log_function
     def push_presence(self, user, statuscache):
-        assert(user.is_mine)
+        assert(self.hs.is_mine(user))
 
         logger.debug("Pushing presence update from %s", user)
 
@@ -659,10 +659,6 @@ class PresenceHandler(BaseHandler):
             if room_ids:
                 logger.debug(" | %d interested room IDs %r", len(room_ids), room_ids)
 
-            if not observers and not room_ids:
-                logger.debug(" | no interested observers or room IDs")
-                continue
-
             state = dict(push)
             del state["user_id"]
 
@@ -683,6 +679,10 @@ class PresenceHandler(BaseHandler):
             self._user_cachemap_latest_serial += 1
             statuscache.update(state, serial=self._user_cachemap_latest_serial)
 
+            if not observers and not room_ids:
+                logger.debug(" | no interested observers or room IDs")
+                continue
+
             self.push_update_to_clients(
                 observed_user=user,
                 users_to_push=observers,
@@ -696,7 +696,7 @@ class PresenceHandler(BaseHandler):
         for poll in content.get("poll", []):
             user = self.hs.parse_userid(poll)
 
-            if not user.is_mine:
+            if not self.hs.is_mine(user):
                 continue
 
             # TODO(paul) permissions checks
@@ -711,7 +711,7 @@ class PresenceHandler(BaseHandler):
         for unpoll in content.get("unpoll", []):
             user = self.hs.parse_userid(unpoll)
 
-            if not user.is_mine:
+            if not self.hs.is_mine(user):
                 continue
 
             if user in self._remote_sendmap:
@@ -730,7 +730,7 @@ class PresenceHandler(BaseHandler):
 
         localusers, remoteusers = partitionbool(
             users_to_push,
-            lambda u: u.is_mine
+            lambda u: self.hs.is_mine(u)
         )
 
         localusers = set(localusers)
@@ -788,7 +788,7 @@ class PresenceEventSource(object):
                 [u.to_string() for u in observer_user, observed_user])):
             defer.returnValue(True)
 
-        if observed_user.is_mine:
+        if self.hs.is_mine(observed_user):
             pushmap = presence._local_pushmap
 
             defer.returnValue(
@@ -804,6 +804,7 @@ class PresenceEventSource(object):
             )
 
     @defer.inlineCallbacks
+    @log_function
     def get_new_events_for_user(self, user, from_key, limit):
         from_key = int(from_key)
 
@@ -816,7 +817,8 @@ class PresenceEventSource(object):
         # TODO(paul): use a DeferredList ? How to limit concurrency.
         for observed_user in cachemap.keys():
             cached = cachemap[observed_user]
-            if not (from_key < cached.serial):
+
+            if cached.serial <= from_key:
                 continue
 
             if (yield self.is_visible(observer_user, observed_user)):
diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py
index 814b3b68fe..33a2c167ec 100644
--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@@ -51,7 +51,7 @@ class ProfileHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def get_displayname(self, target_user):
-        if target_user.is_mine:
+        if self.hs.is_mine(target_user):
             displayname = yield self.store.get_profile_displayname(
                 target_user.localpart
             )
@@ -81,7 +81,7 @@ class ProfileHandler(BaseHandler):
     def set_displayname(self, target_user, auth_user, new_displayname):
         """target_user is the user whose displayname is to be changed;
         auth_user is the user attempting to make this change."""
-        if not target_user.is_mine:
+        if not self.hs.is_mine(target_user):
             raise SynapseError(400, "User is not hosted on this Home Server")
 
         if target_user != auth_user:
@@ -101,7 +101,7 @@ class ProfileHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def get_avatar_url(self, target_user):
-        if target_user.is_mine:
+        if self.hs.is_mine(target_user):
             avatar_url = yield self.store.get_profile_avatar_url(
                 target_user.localpart
             )
@@ -130,7 +130,7 @@ class ProfileHandler(BaseHandler):
     def set_avatar_url(self, target_user, auth_user, new_avatar_url):
         """target_user is the user whose avatar_url is to be changed;
         auth_user is the user attempting to make this change."""
-        if not target_user.is_mine:
+        if not self.hs.is_mine(target_user):
             raise SynapseError(400, "User is not hosted on this Home Server")
 
         if target_user != auth_user:
@@ -150,7 +150,7 @@ class ProfileHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def collect_presencelike_data(self, user, state):
-        if not user.is_mine:
+        if not self.hs.is_mine(user):
             defer.returnValue(None)
 
         with PreserveLoggingContext():
@@ -170,7 +170,7 @@ class ProfileHandler(BaseHandler):
     @defer.inlineCallbacks
     def on_profile_query(self, args):
         user = self.hs.parse_userid(args["user_id"])
-        if not user.is_mine:
+        if not self.hs.is_mine(user):
             raise SynapseError(400, "User is not hosted on this Home Server")
 
         just_field = args.get("field", None)
@@ -191,7 +191,7 @@ class ProfileHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def _update_join_states(self, user):
-        if not user.is_mine:
+        if not self.hs.is_mine(user):
             return
 
         joins = yield self.store.get_rooms_for_user_where_membership_is(
@@ -200,8 +200,6 @@ class ProfileHandler(BaseHandler):
         )
 
         for j in joins:
-            snapshot = yield self.store.snapshot_room(j)
-
             content = {
                 "membership": j.content["membership"],
             }
@@ -210,14 +208,11 @@ class ProfileHandler(BaseHandler):
                 "collect_presencelike_data", user, content
             )
 
-            new_event = self.event_factory.create_event(
-                etype=j.type,
-                room_id=j.room_id,
-                state_key=j.state_key,
-                content=content,
-                user_id=j.state_key,
-            )
-
-            yield self._on_new_room_event(
-                new_event, snapshot, suppress_auth=True
-            )
+            msg_handler = self.hs.get_handlers().message_handler
+            yield msg_handler.create_and_send_event({
+                "type": j.type,
+                "room_id": j.room_id,
+                "state_key": j.state_key,
+                "content": content,
+                "sender": j.state_key,
+            })
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index 48c326ebf0..15d8716455 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -22,6 +22,7 @@ from synapse.api.errors import (
 )
 from ._base import BaseHandler
 import synapse.util.stringutils as stringutils
+from synapse.util.async import run_on_reactor
 from synapse.http.client import SimpleHttpClient
 from synapse.http.client import CaptchaServerHttpClient
 
@@ -54,12 +55,13 @@ class RegistrationHandler(BaseHandler):
         Raises:
             RegistrationError if there was a problem registering.
         """
+        yield run_on_reactor()
         password_hash = None
         if password:
             password_hash = bcrypt.hashpw(password, bcrypt.gensalt())
 
         if localpart:
-            user = UserID(localpart, self.hs.hostname, True)
+            user = UserID(localpart, self.hs.hostname)
             user_id = user.to_string()
 
             token = self._generate_token(user_id)
@@ -78,7 +80,7 @@ class RegistrationHandler(BaseHandler):
             while not user_id and not token:
                 try:
                     localpart = self._generate_user_id()
-                    user = UserID(localpart, self.hs.hostname, True)
+                    user = UserID(localpart, self.hs.hostname)
                     user_id = user.to_string()
 
                     token = self._generate_token(user_id)
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index a000b44036..8567d7409d 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -17,12 +17,8 @@
 from twisted.internet import defer
 
 from synapse.types import UserID, RoomAlias, RoomID
-from synapse.api.constants import Membership, JoinRules
+from synapse.api.constants import EventTypes, Membership, JoinRules
 from synapse.api.errors import StoreError, SynapseError
-from synapse.api.events.room import (
-    RoomMemberEvent, RoomCreateEvent, RoomPowerLevelsEvent,
-    RoomTopicEvent, RoomNameEvent, RoomJoinRulesEvent,
-)
 from synapse.util import stringutils
 from synapse.util.async import run_on_reactor
 from ._base import BaseHandler
@@ -52,9 +48,9 @@ class RoomCreationHandler(BaseHandler):
         self.ratelimit(user_id)
 
         if "room_alias_name" in config:
-            room_alias = RoomAlias.create_local(
+            room_alias = RoomAlias.create(
                 config["room_alias_name"],
-                self.hs
+                self.hs.hostname,
             )
             mapping = yield self.store.get_association_from_room_alias(
                 room_alias
@@ -76,8 +72,8 @@ class RoomCreationHandler(BaseHandler):
 
         if room_id:
             # Ensure room_id is the correct type
-            room_id_obj = RoomID.from_string(room_id, self.hs)
-            if not room_id_obj.is_mine:
+            room_id_obj = RoomID.from_string(room_id)
+            if not self.hs.is_mine(room_id_obj):
                 raise SynapseError(400, "Room id must be local")
 
             yield self.store.store_room(
@@ -93,7 +89,10 @@ class RoomCreationHandler(BaseHandler):
             while attempts < 5:
                 try:
                     random_string = stringutils.random_string(18)
-                    gen_room_id = RoomID.create_local(random_string, self.hs)
+                    gen_room_id = RoomID.create(
+                        random_string,
+                        self.hs.hostname,
+                    )
                     yield self.store.store_room(
                         room_id=gen_room_id.to_string(),
                         room_creator_user_id=user_id,
@@ -120,59 +119,37 @@ class RoomCreationHandler(BaseHandler):
             user, room_id, is_public=is_public
         )
 
-        room_member_handler = self.hs.get_handlers().room_member_handler
-
-        @defer.inlineCallbacks
-        def handle_event(event):
-            snapshot = yield self.store.snapshot_room(event)
-
-            logger.debug("Event: %s", event)
-
-            if event.type == RoomMemberEvent.TYPE:
-                yield room_member_handler.change_membership(
-                    event,
-                    do_auth=True
-                )
-            else:
-                yield self._on_new_room_event(
-                    event, snapshot, extra_users=[user], suppress_auth=True
-                )
+        msg_handler = self.hs.get_handlers().message_handler
 
         for event in creation_events:
-            yield handle_event(event)
+            yield msg_handler.create_and_send_event(event)
 
         if "name" in config:
             name = config["name"]
-            name_event = self.event_factory.create_event(
-                etype=RoomNameEvent.TYPE,
-                room_id=room_id,
-                user_id=user_id,
-                content={"name": name},
-            )
-
-            yield handle_event(name_event)
+            yield msg_handler.create_and_send_event({
+                "type": EventTypes.Name,
+                "room_id": room_id,
+                "sender": user_id,
+                "content": {"name": name},
+            })
 
         if "topic" in config:
             topic = config["topic"]
-            topic_event = self.event_factory.create_event(
-                etype=RoomTopicEvent.TYPE,
-                room_id=room_id,
-                user_id=user_id,
-                content={"topic": topic},
-            )
+            yield msg_handler.create_and_send_event({
+                "type": EventTypes.Topic,
+                "room_id": room_id,
+                "sender": user_id,
+                "content": {"topic": topic},
+            })
 
-            yield handle_event(topic_event)
-
-        content = {"membership": Membership.INVITE}
         for invitee in invite_list:
-            invite_event = self.event_factory.create_event(
-                etype=RoomMemberEvent.TYPE,
-                state_key=invitee,
-                room_id=room_id,
-                user_id=user_id,
-                content=content
-            )
-            yield handle_event(invite_event)
+            yield msg_handler.create_and_send_event({
+                "type": EventTypes.Member,
+                "state_key": invitee,
+                "room_id": room_id,
+                "user_id": user_id,
+                "content": {"membership": Membership.INVITE},
+            })
 
         result = {"room_id": room_id}
 
@@ -189,40 +166,44 @@ class RoomCreationHandler(BaseHandler):
 
         event_keys = {
             "room_id": room_id,
-            "user_id": creator_id,
+            "sender": creator_id,
+            "state_key": "",
         }
 
-        def create(etype, **content):
-            return self.event_factory.create_event(
-                etype=etype,
-                content=content,
-                **event_keys
-            )
+        def create(etype, content, **kwargs):
+            e = {
+                "type": etype,
+                "content": content,
+            }
+
+            e.update(event_keys)
+            e.update(kwargs)
+
+            return e
 
         creation_event = create(
-            etype=RoomCreateEvent.TYPE,
-            creator=creator.to_string(),
+            etype=EventTypes.Create,
+            content={"creator": creator.to_string()},
         )
 
-        join_event = self.event_factory.create_event(
-            etype=RoomMemberEvent.TYPE,
+        join_event = create(
+            etype=EventTypes.Member,
             state_key=creator_id,
             content={
                 "membership": Membership.JOIN,
             },
-            **event_keys
         )
 
-        power_levels_event = self.event_factory.create_event(
-            etype=RoomPowerLevelsEvent.TYPE,
+        power_levels_event = create(
+            etype=EventTypes.PowerLevels,
             content={
                 "users": {
                     creator.to_string(): 100,
                 },
                 "users_default": 0,
                 "events": {
-                    RoomNameEvent.TYPE: 100,
-                    RoomPowerLevelsEvent.TYPE: 100,
+                    EventTypes.Name: 100,
+                    EventTypes.PowerLevels: 100,
                 },
                 "events_default": 0,
                 "state_default": 50,
@@ -230,13 +211,12 @@ class RoomCreationHandler(BaseHandler):
                 "kick": 50,
                 "redact": 50
             },
-            **event_keys
         )
 
         join_rule = JoinRules.PUBLIC if is_public else JoinRules.INVITE
         join_rules_event = create(
-            etype=RoomJoinRulesEvent.TYPE,
-            join_rule=join_rule,
+            etype=EventTypes.JoinRules,
+            content={"join_rule": join_rule},
         )
 
         return [
@@ -260,6 +240,7 @@ class RoomMemberHandler(BaseHandler):
 
         self.distributor = hs.get_distributor()
         self.distributor.declare("user_joined_room")
+        self.distributor.declare("user_left_room")
 
     @defer.inlineCallbacks
     def get_room_members(self, room_id, membership=Membership.JOIN):
@@ -287,7 +268,7 @@ class RoomMemberHandler(BaseHandler):
             if ignore_user is not None and member == ignore_user:
                 continue
 
-            if member.is_mine:
+            if self.hs.is_mine(member):
                 if localusers is not None:
                     localusers.add(member)
             else:
@@ -348,7 +329,7 @@ class RoomMemberHandler(BaseHandler):
         defer.returnValue(member)
 
     @defer.inlineCallbacks
-    def change_membership(self, event=None, do_auth=True):
+    def change_membership(self, event, context, do_auth=True):
         """ Change the membership status of a user in a room.
 
         Args:
@@ -358,11 +339,9 @@ class RoomMemberHandler(BaseHandler):
         """
         target_user_id = event.state_key
 
-        snapshot = yield self.store.snapshot_room(event)
-
-        ## TODO(markjh): get prev state from snapshot.
-        prev_state = yield self.store.get_room_member(
-            target_user_id, event.room_id
+        prev_state = context.current_state.get(
+            (EventTypes.Member, target_user_id),
+            None
         )
 
         room_id = event.room_id
@@ -371,10 +350,11 @@ class RoomMemberHandler(BaseHandler):
         # if this HS is not currently in the room, i.e. we have to do the
         # invite/join dance.
         if event.membership == Membership.JOIN:
-            yield self._do_join(event, snapshot, do_auth=do_auth)
+            yield self._do_join(event, context, do_auth=do_auth)
         else:
             # This is not a JOIN, so we can handle it normally.
 
+            # FIXME: This isn't idempotency.
             if prev_state and prev_state.membership == event.membership:
                 # double same action, treat this event as a NOOP.
                 defer.returnValue({})
@@ -383,10 +363,16 @@ class RoomMemberHandler(BaseHandler):
             yield self._do_local_membership_update(
                 event,
                 membership=event.content["membership"],
-                snapshot=snapshot,
+                context=context,
                 do_auth=do_auth,
             )
 
+            if prev_state and prev_state.membership == Membership.JOIN:
+                user = self.hs.parse_userid(event.user_id)
+                self.distributor.fire(
+                    "user_left_room", user=user, room_id=event.room_id
+                )
+
         defer.returnValue({"room_id": room_id})
 
     @defer.inlineCallbacks
@@ -405,32 +391,26 @@ class RoomMemberHandler(BaseHandler):
         host = hosts[0]
 
         content.update({"membership": Membership.JOIN})
-        new_event = self.event_factory.create_event(
-            etype=RoomMemberEvent.TYPE,
-            state_key=joinee.to_string(),
-            room_id=room_id,
-            user_id=joinee.to_string(),
-            membership=Membership.JOIN,
-            content=content,
-        )
-
-        snapshot = yield self.store.snapshot_room(new_event)
+        builder = self.event_builder_factory.new({
+            "type": EventTypes.Member,
+            "state_key": joinee.to_string(),
+            "room_id": room_id,
+            "sender": joinee.to_string(),
+            "membership": Membership.JOIN,
+            "content": content,
+        })
+        event, context = yield self._create_new_client_event(builder)
 
-        yield self._do_join(new_event, snapshot, room_host=host, do_auth=True)
+        yield self._do_join(event, context, room_host=host, do_auth=True)
 
         defer.returnValue({"room_id": room_id})
 
     @defer.inlineCallbacks
-    def _do_join(self, event, snapshot, room_host=None, do_auth=True):
+    def _do_join(self, event, context, room_host=None, do_auth=True):
         joinee = self.hs.parse_userid(event.state_key)
         # room_id = RoomID.from_string(event.room_id, self.hs)
         room_id = event.room_id
 
-        # If event doesn't include a display name, add one.
-        yield self.distributor.fire(
-            "collect_presencelike_data", joinee, event.content
-        )
-
         # XXX: We don't do an auth check if we are doing an invite
         # join dance for now, since we're kinda implicitly checking
         # that we are allowed to join when we decide whether or not we
@@ -452,31 +432,29 @@ class RoomMemberHandler(BaseHandler):
             )
 
             if prev_state and prev_state.membership == Membership.INVITE:
-                room = yield self.store.get_room(room_id)
-                inviter = UserID.from_string(
-                    prev_state.user_id, self.hs
-                )
+                inviter = UserID.from_string(prev_state.user_id)
 
-                should_do_dance = not inviter.is_mine and not room
+                should_do_dance = not self.hs.is_mine(inviter)
                 room_host = inviter.domain
             else:
                 should_do_dance = False
 
-        have_joined = False
         if should_do_dance:
             handler = self.hs.get_handlers().federation_handler
-            have_joined = yield handler.do_invite_join(
-                room_host, room_id, event.user_id, event.content, snapshot
+            yield handler.do_invite_join(
+                room_host,
+                room_id,
+                event.user_id,
+                event.get_dict()["content"],  # FIXME To get a non-frozen dict
+                context
             )
-
-        # We want to do the _do_update inside the room lock.
-        if not have_joined:
+        else:
             logger.debug("Doing normal join")
 
             yield self._do_local_membership_update(
                 event,
                 membership=event.content["membership"],
-                snapshot=snapshot,
+                context=context,
                 do_auth=do_auth,
             )
 
@@ -501,10 +479,10 @@ class RoomMemberHandler(BaseHandler):
         if prev_state and prev_state.membership == Membership.INVITE:
             room = yield self.store.get_room(room_id)
             inviter = UserID.from_string(
-                prev_state.sender, self.hs
+                prev_state.sender
             )
 
-            is_remote_invite_join = not inviter.is_mine and not room
+            is_remote_invite_join = not self.hs.is_mine(inviter) and not room
             room_host = inviter.domain
         else:
             is_remote_invite_join = False
@@ -526,25 +504,17 @@ class RoomMemberHandler(BaseHandler):
         defer.returnValue(room_ids)
 
     @defer.inlineCallbacks
-    def _do_local_membership_update(self, event, membership, snapshot,
+    def _do_local_membership_update(self, event, membership, context,
                                     do_auth):
         yield run_on_reactor()
 
-        # If we're inviting someone, then we should also send it to that
-        # HS.
-        target_user_id = event.state_key
-        target_user = self.hs.parse_userid(target_user_id)
-        if membership == Membership.INVITE and not target_user.is_mine:
-            do_invite_host = target_user.domain
-        else:
-            do_invite_host = None
+        target_user = self.hs.parse_userid(event.state_key)
 
-        yield self._on_new_room_event(
+        yield self.handle_new_client_event(
             event,
-            snapshot,
+            context,
             extra_users=[target_user],
             suppress_auth=(not do_auth),
-            do_invite_host=do_invite_host,
         )
 
 
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py
index d88a53242c..7626b07280 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -43,22 +43,50 @@ class TypingNotificationHandler(BaseHandler):
 
         self.federation.register_edu_handler("m.typing", self._recv_edu)
 
-        self._member_typing_until = {}
+        hs.get_distributor().observe("user_left_room", self.user_left_room)
+
+        self._member_typing_until = {}  # clock time we expect to stop
+        self._member_typing_timer = {}  # deferreds to manage theabove
+
+        # map room IDs to serial numbers
+        self._room_serials = {}
+        self._latest_room_serial = 0
+        # map room IDs to sets of users currently typing
+        self._room_typing = {}
+
+    def tearDown(self):
+        """Cancels all the pending timers.
+        Normally this shouldn't be needed, but it's required from unit tests
+        to avoid a "Reactor was unclean" warning."""
+        for t in self._member_typing_timer.values():
+            self.clock.cancel_call_later(t)
 
     @defer.inlineCallbacks
     def started_typing(self, target_user, auth_user, room_id, timeout):
-        if not target_user.is_mine:
+        if not self.hs.is_mine(target_user):
             raise SynapseError(400, "User is not hosted on this Home Server")
 
         if target_user != auth_user:
             raise AuthError(400, "Cannot set another user's typing state")
 
+        yield self.auth.check_joined_room(room_id, target_user.to_string())
+
+        logger.debug(
+            "%s has started typing in %s", target_user.to_string(), room_id
+        )
+
         until = self.clock.time_msec() + timeout
         member = RoomMember(room_id=room_id, user=target_user)
 
         was_present = member in self._member_typing_until
 
+        if member in self._member_typing_timer:
+            self.clock.cancel_call_later(self._member_typing_timer[member])
+
         self._member_typing_until[member] = until
+        self._member_typing_timer[member] = self.clock.call_later(
+            timeout / 1000, lambda: self._stopped_typing(member)
+        )
 
         if was_present:
             # No point sending another notification
@@ -72,24 +100,45 @@ class TypingNotificationHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def stopped_typing(self, target_user, auth_user, room_id):
-        if not target_user.is_mine:
+        if not self.hs.is_mine(target_user):
             raise SynapseError(400, "User is not hosted on this Home Server")
 
         if target_user != auth_user:
             raise AuthError(400, "Cannot set another user's typing state")
 
+        yield self.auth.check_joined_room(room_id, target_user.to_string())
+
+        logger.debug(
+            "%s has stopped typing in %s", target_user.to_string(), room_id
+        )
+
         member = RoomMember(room_id=room_id, user=target_user)
 
+        yield self._stopped_typing(member)
+
+    @defer.inlineCallbacks
+    def user_left_room(self, user, room_id):
+        if self.hs.is_mine(user):
+            member = RoomMember(room_id=room_id, user=user)
+            yield self._stopped_typing(member)
+
+    @defer.inlineCallbacks
+    def _stopped_typing(self, member):
         if member not in self._member_typing_until:
             # No point
             defer.returnValue(None)
 
         yield self._push_update(
-            room_id=room_id,
-            user=target_user,
+            room_id=member.room_id,
+            user=member.user,
             typing=False,
         )
 
+        del self._member_typing_until[member]
+
+        self.clock.cancel_call_later(self._member_typing_timer[member])
+        del self._member_typing_timer[member]
+
     @defer.inlineCallbacks
     def _push_update(self, room_id, user, typing):
         localusers = set()
@@ -97,16 +146,14 @@ class TypingNotificationHandler(BaseHandler):
 
         rm_handler = self.homeserver.get_handlers().room_member_handler
         yield rm_handler.fetch_room_distributions_into(
-            room_id, localusers=localusers, remotedomains=remotedomains,
-            ignore_user=user
+            room_id, localusers=localusers, remotedomains=remotedomains
         )
 
-        for u in localusers:
-            self.push_update_to_clients(
+        if localusers:
+            self._push_update_local(
                 room_id=room_id,
-                observer_user=u,
-                observed_user=user,
-                typing=typing,
+                user=user,
+                typing=typing
             )
 
         deferreds = []
@@ -135,29 +182,67 @@ class TypingNotificationHandler(BaseHandler):
             room_id, localusers=localusers
         )
 
-        for u in localusers:
-            self.push_update_to_clients(
+        if localusers:
+            self._push_update_local(
                 room_id=room_id,
-                observer_user=u,
-                observed_user=user,
+                user=user,
                 typing=content["typing"]
             )
 
-    def push_update_to_clients(self, room_id, observer_user, observed_user,
-                               typing):
-        # TODO(paul) steal this from presence.py
-        pass
+    def _push_update_local(self, room_id, user, typing):
+        if room_id not in self._room_serials:
+            self._room_serials[room_id] = 0
+            self._room_typing[room_id] = set()
+
+        room_set = self._room_typing[room_id]
+        if typing:
+            room_set.add(user)
+        elif user in room_set:
+            room_set.remove(user)
+
+        self._latest_room_serial += 1
+        self._room_serials[room_id] = self._latest_room_serial
+
+        self.notifier.on_new_user_event(rooms=[room_id])
 
 
 class TypingNotificationEventSource(object):
     def __init__(self, hs):
         self.hs = hs
+        self._handler = None
+
+    def handler(self):
+        # Avoid cyclic dependency in handler setup
+        if not self._handler:
+            self._handler = self.hs.get_handlers().typing_notification_handler
+        return self._handler
+
+    def _make_event_for(self, room_id):
+        typing = self.handler()._room_typing[room_id]
+        return {
+            "type": "m.typing",
+            "room_id": room_id,
+            "content": {
+                "user_ids": [u.to_string() for u in typing],
+            },
+        }
 
     def get_new_events_for_user(self, user, from_key, limit):
-        return ([], from_key)
+        from_key = int(from_key)
+        handler = self.handler()
+
+        events = []
+        for room_id in handler._room_serials:
+            if handler._room_serials[room_id] <= from_key:
+                continue
+
+            # TODO: check if user is in room
+            events.append(self._make_event_for(room_id))
+
+        return (events, handler._latest_room_serial)
 
     def get_current_key(self):
-        return 0
+        return self.handler()._latest_room_serial
 
     def get_pagination_rows(self, user, pagination_config, key):
         return ([], pagination_config.from_key)
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index 510f07dd7b..8f4db59c75 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -14,10 +14,11 @@
 # limitations under the License.
 
 
-from twisted.internet import defer, reactor
+from twisted.internet import defer, reactor, protocol
 from twisted.internet.error import DNSLookupError
 from twisted.web.client import readBody, _AgentBase, _URI
 from twisted.web.http_headers import Headers
+from twisted.web._newclient import ResponseDone
 
 from synapse.http.endpoint import matrix_federation_endpoint
 from synapse.util.async import sleep
@@ -25,7 +26,7 @@ from synapse.util.logcontext import PreserveLoggingContext
 
 from syutil.jsonutil import encode_canonical_json
 
-from synapse.api.errors import CodeMessageException, SynapseError
+from synapse.api.errors import CodeMessageException, SynapseError, Codes
 
 from syutil.crypto.jsonsign import sign_json
 
@@ -89,8 +90,8 @@ class MatrixFederationHttpClient(object):
             ("", "", path_bytes, param_bytes, query_bytes, "",)
         )
 
-        logger.debug("Sending request to %s: %s %s",
-                     destination, method, url_bytes)
+        logger.info("Sending request to %s: %s %s",
+                    destination, method, url_bytes)
 
         logger.debug(
             "Types: %s",
@@ -101,6 +102,8 @@ class MatrixFederationHttpClient(object):
             ]
         )
 
+        # XXX: Would be much nicer to retry only at the transaction-layer
+        # (once we have reliable transactions in place)
         retries_left = 5
 
         endpoint = self._getEndpoint(reactor, destination)
@@ -127,11 +130,20 @@ class MatrixFederationHttpClient(object):
                 break
             except Exception as e:
                 if not retry_on_dns_fail and isinstance(e, DNSLookupError):
-                    logger.warn("DNS Lookup failed to %s with %s", destination,
-                                e)
+                    logger.warn(
+                        "DNS Lookup failed to %s with %s",
+                        destination,
+                        e
+                    )
                     raise SynapseError(400, "Domain specified not found.")
 
-                logger.exception("Got error in _create_request")
+                logger.warn(
+                    "Sending request failed to %s: %s %s : %s",
+                    destination,
+                    method,
+                    url_bytes,
+                    e
+                )
                 _print_ex(e)
 
                 if retries_left:
@@ -140,15 +152,21 @@ class MatrixFederationHttpClient(object):
                 else:
                     raise
 
+        logger.info(
+            "Received response %d %s for %s: %s %s",
+            response.code,
+            response.phrase,
+            destination,
+            method,
+            url_bytes
+        )
+
         if 200 <= response.code < 300:
             # We need to update the transactions table to say it was sent?
             pass
         else:
             # :'(
             # Update transactions table?
-            logger.error(
-                "Got response %d %s", response.code, response.phrase
-            )
             raise CodeMessageException(
                 response.code, response.phrase
             )
@@ -227,7 +245,7 @@ class MatrixFederationHttpClient(object):
 
     @defer.inlineCallbacks
     def get_json(self, destination, path, args={}, retry_on_dns_fail=True):
-        """ Get's some json from the given host homeserver and path
+        """ GETs some json from the given host homeserver and path
 
         Args:
             destination (str): The remote server to send the HTTP request
@@ -235,9 +253,6 @@ class MatrixFederationHttpClient(object):
             path (str): The HTTP path.
             args (dict): A dictionary used to create query strings, defaults to
                 None.
-                **Note**: The value of each key is assumed to be an iterable
-                and *not* a string.
-
         Returns:
             Deferred: Succeeds when we get *any* HTTP response.
 
@@ -272,6 +287,52 @@ class MatrixFederationHttpClient(object):
 
         defer.returnValue(json.loads(body))
 
+    @defer.inlineCallbacks
+    def get_file(self, destination, path, output_stream, args={},
+                 retry_on_dns_fail=True, max_size=None):
+        """GETs a file from a given homeserver
+        Args:
+            destination (str): The remote server to send the HTTP request to.
+            path (str): The HTTP path to GET.
+            output_stream (file): File to write the response body to.
+            args (dict): Optional dictionary used to create the query string.
+        Returns:
+            A (int,dict) tuple of the file length and a dict of the response
+            headers.
+        """
+
+        encoded_args = {}
+        for k, vs in args.items():
+            if isinstance(vs, basestring):
+                vs = [vs]
+            encoded_args[k] = [v.encode("UTF-8") for v in vs]
+
+        query_bytes = urllib.urlencode(encoded_args, True)
+        logger.debug("Query bytes: %s Retry DNS: %s", args, retry_on_dns_fail)
+
+        def body_callback(method, url_bytes, headers_dict):
+            self.sign_request(destination, method, url_bytes, headers_dict)
+            return None
+
+        response = yield self._create_request(
+            destination.encode("ascii"),
+            "GET",
+            path.encode("ascii"),
+            query_bytes=query_bytes,
+            body_callback=body_callback,
+            retry_on_dns_fail=retry_on_dns_fail
+        )
+
+        headers = dict(response.headers.getAllRawHeaders())
+
+        try:
+            length = yield _readBodyToFile(response, output_stream, max_size)
+        except:
+            logger.exception("Failed to download body")
+            raise
+
+        defer.returnValue((length, headers))
+
     def _getEndpoint(self, reactor, destination):
         return matrix_federation_endpoint(
             reactor, destination, timeout=10,
@@ -279,12 +340,44 @@ class MatrixFederationHttpClient(object):
         )
 
 
+class _ReadBodyToFileProtocol(protocol.Protocol):
+    def __init__(self, stream, deferred, max_size):
+        self.stream = stream
+        self.deferred = deferred
+        self.length = 0
+        self.max_size = max_size
+
+    def dataReceived(self, data):
+        self.stream.write(data)
+        self.length += len(data)
+        if self.max_size is not None and self.length >= self.max_size:
+            self.deferred.errback(SynapseError(
+                502,
+                "Requested file is too large > %r bytes" % (self.max_size,),
+                Codes.TOO_LARGE,
+            ))
+            self.deferred = defer.Deferred()
+            self.transport.loseConnection()
+
+    def connectionLost(self, reason):
+        if reason.check(ResponseDone):
+            self.deferred.callback(self.length)
+        else:
+            self.deferred.errback(reason)
+
+
+def _readBodyToFile(response, stream, max_size):
+    d = defer.Deferred()
+    response.deliverBody(_ReadBodyToFileProtocol(stream, d, max_size))
+    return d
+
+
 def _print_ex(e):
     if hasattr(e, "reasons") and e.reasons:
         for ex in e.reasons:
             _print_ex(ex)
     else:
-        logger.exception(e)
+        logger.warn(e)
 
 
 class _JsonProducer(object):
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 8024ff5bde..f33859cf76 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -29,6 +29,7 @@ from twisted.web.util import redirectTo
 
 import collections
 import logging
+import urllib
 
 logger = logging.getLogger(__name__)
 
@@ -122,9 +123,14 @@ class JsonResource(HttpServer, resource.Resource):
                     # We found a match! Trigger callback and then return the
                     # returned response. We pass both the request and any
                     # matched groups from the regex to the callback.
+
+                    args = [
+                        urllib.unquote(u).decode("UTF-8") for u in m.groups()
+                    ]
+
                     code, response = yield path_entry.callback(
                         request,
-                        *m.groups()
+                        *args
                     )
 
                     self._send_response(request, code, response)
@@ -166,14 +172,10 @@ class JsonResource(HttpServer, resource.Resource):
                 request)
             return
 
-        if not self._request_user_agent_is_curl(request):
-            json_bytes = encode_canonical_json(response_json_object)
-        else:
-            json_bytes = encode_pretty_printed_json(response_json_object)
-
         # TODO: Only enable CORS for the requests that need it.
-        respond_with_json_bytes(request, code, json_bytes, send_cors=True,
-                                response_code_message=response_code_message)
+        respond_with_json(request, code, response_json_object, send_cors=True,
+                          response_code_message=response_code_message,
+                          pretty_print=self._request_user_agent_is_curl)
 
     @staticmethod
     def _request_user_agent_is_curl(request):
@@ -202,6 +204,17 @@ class RootRedirect(resource.Resource):
         return resource.Resource.getChild(self, name, request)
 
 
+def respond_with_json(request, code, json_object, send_cors=False,
+                      response_code_message=None, pretty_print=False):
+    if not pretty_print:
+        json_bytes = encode_pretty_printed_json(json_object)
+    else:
+        json_bytes = encode_canonical_json(json_object)
+
+    return respond_with_json_bytes(request, code, json_bytes, send_cors,
+                                   response_code_message=response_code_message)
+
+
 def respond_with_json_bytes(request, code, json_bytes, send_cors=False,
                             response_code_message=None):
     """Sends encoded JSON in response to the given request.
diff --git a/synapse/media/__init__.py b/synapse/media/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/synapse/media/__init__.py
diff --git a/synapse/media/v0/__init__.py b/synapse/media/v0/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/synapse/media/v0/__init__.py
diff --git a/synapse/http/content_repository.py b/synapse/media/v0/content_repository.py
index 64ecb5346e..ce5d3d153e 100644
--- a/synapse/http/content_repository.py
+++ b/synapse/media/v0/content_repository.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .server import respond_with_json_bytes
+from synapse.http.server import respond_with_json_bytes
 
 from synapse.util.stringutils import random_string
 from synapse.api.errors import (
diff --git a/synapse/media/v1/__init__.py b/synapse/media/v1/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/synapse/media/v1/__init__.py
diff --git a/synapse/media/v1/base_resource.py b/synapse/media/v1/base_resource.py
new file mode 100644
index 0000000000..2f5440ab64
--- /dev/null
+++ b/synapse/media/v1/base_resource.py
@@ -0,0 +1,369 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .thumbnailer import Thumbnailer
+
+from synapse.http.server import respond_with_json
+from synapse.util.stringutils import random_string
+from synapse.api.errors import (
+    cs_exception, CodeMessageException, cs_error, Codes, SynapseError
+)
+
+from twisted.internet import defer
+from twisted.web.resource import Resource
+from twisted.protocols.basic import FileSender
+
+import os
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class BaseMediaResource(Resource):
+    isLeaf = True
+
+    def __init__(self, hs, filepaths):
+        Resource.__init__(self)
+        self.auth = hs.get_auth()
+        self.client = hs.get_http_client()
+        self.clock = hs.get_clock()
+        self.server_name = hs.hostname
+        self.store = hs.get_datastore()
+        self.max_upload_size = hs.config.max_upload_size
+        self.max_image_pixels = hs.config.max_image_pixels
+        self.filepaths = filepaths
+        self.downloads = {}
+
+    @staticmethod
+    def catch_errors(request_handler):
+        @defer.inlineCallbacks
+        def wrapped_request_handler(self, request):
+            try:
+                yield request_handler(self, request)
+            except CodeMessageException as e:
+                logger.exception(e)
+                respond_with_json(
+                    request, e.code, cs_exception(e), send_cors=True
+                )
+            except:
+                logger.exception(
+                    "Failed handle request %s.%s on %r",
+                    request_handler.__module__,
+                    request_handler.__name__,
+                    self,
+                )
+                respond_with_json(
+                    request,
+                    500,
+                    {"error": "Internal server error"},
+                    send_cors=True
+                )
+        return wrapped_request_handler
+
+    @staticmethod
+    def _parse_media_id(request):
+        try:
+            server_name, media_id = request.postpath
+            return (server_name, media_id)
+        except:
+            raise SynapseError(
+                404,
+                "Invalid media id token %r" % (request.postpath,),
+                Codes.UNKKOWN,
+            )
+
+    @staticmethod
+    def _parse_integer(request, arg_name, default=None):
+        try:
+            if default is None:
+                return int(request.args[arg_name][0])
+            else:
+                return int(request.args.get(arg_name, [default])[0])
+        except:
+            raise SynapseError(
+                400,
+                "Missing integer argument %r" % (arg_name,),
+                Codes.UNKNOWN,
+            )
+
+    @staticmethod
+    def _parse_string(request, arg_name, default=None):
+        try:
+            if default is None:
+                return request.args[arg_name][0]
+            else:
+                return request.args.get(arg_name, [default])[0]
+        except:
+            raise SynapseError(
+                400,
+                "Missing string argument %r" % (arg_name,),
+                Codes.UNKNOWN,
+            )
+
+    def _respond_404(self, request):
+        respond_with_json(
+            request, 404,
+            cs_error(
+                "Not found %r" % (request.postpath,),
+                code=Codes.NOT_FOUND,
+            ),
+            send_cors=True
+        )
+
+    @staticmethod
+    def _makedirs(filepath):
+        dirname = os.path.dirname(filepath)
+        if not os.path.exists(dirname):
+            os.makedirs(dirname)
+
+    def _get_remote_media(self, server_name, media_id):
+        key = (server_name, media_id)
+        download = self.downloads.get(key)
+        if download is None:
+            download = self._get_remote_media_impl(server_name, media_id)
+            self.downloads[key] = download
+
+            @download.addBoth
+            def callback(media_info):
+                del self.downloads[key]
+        return download
+
+    @defer.inlineCallbacks
+    def _get_remote_media_impl(self, server_name, media_id):
+        media_info = yield self.store.get_cached_remote_media(
+            server_name, media_id
+        )
+        if not media_info:
+            media_info = yield self._download_remote_file(
+                server_name, media_id
+            )
+        defer.returnValue(media_info)
+
+    @defer.inlineCallbacks
+    def _download_remote_file(self, server_name, media_id):
+        file_id = random_string(24)
+
+        fname = self.filepaths.remote_media_filepath(
+            server_name, file_id
+        )
+        self._makedirs(fname)
+
+        try:
+            with open(fname, "wb") as f:
+                request_path = "/".join((
+                    "/_matrix/media/v1/download", server_name, media_id,
+                ))
+                length, headers = yield self.client.get_file(
+                    server_name, request_path, output_stream=f,
+                    max_size=self.max_upload_size,
+                )
+            media_type = headers["Content-Type"][0]
+            time_now_ms = self.clock.time_msec()
+
+            yield self.store.store_cached_remote_media(
+                origin=server_name,
+                media_id=media_id,
+                media_type=media_type,
+                time_now_ms=self.clock.time_msec(),
+                upload_name=None,
+                media_length=length,
+                filesystem_id=file_id,
+            )
+        except:
+            os.remove(fname)
+            raise
+
+        media_info = {
+            "media_type": media_type,
+            "media_length": length,
+            "upload_name": None,
+            "created_ts": time_now_ms,
+            "filesystem_id": file_id,
+        }
+
+        yield self._generate_remote_thumbnails(
+            server_name, media_id, media_info
+        )
+
+        defer.returnValue(media_info)
+
+    @defer.inlineCallbacks
+    def _respond_with_file(self, request, media_type, file_path):
+        logger.debug("Responding with %r", file_path)
+
+        if os.path.isfile(file_path):
+            request.setHeader(b"Content-Type", media_type.encode("UTF-8"))
+
+            # cache for at least a day.
+            # XXX: we might want to turn this off for data we don't want to
+            # recommend caching as it's sensitive or private - or at least
+            # select private. don't bother setting Expires as all our
+            # clients are smart enough to be happy with Cache-Control
+            request.setHeader(
+                b"Cache-Control", b"public,max-age=86400,s-maxage=86400"
+            )
+
+            with open(file_path, "rb") as f:
+                yield FileSender().beginFileTransfer(f, request)
+
+            request.finish()
+        else:
+            self._respond_404()
+
+    def _get_thumbnail_requirements(self, media_type):
+        if media_type == "image/jpeg":
+            return (
+                (32, 32, "crop", "image/jpeg"),
+                (96, 96, "crop", "image/jpeg"),
+                (320, 240, "scale", "image/jpeg"),
+                (640, 480, "scale", "image/jpeg"),
+            )
+        elif (media_type == "image/png") or (media_type == "image/gif"):
+            return (
+                (32, 32, "crop", "image/png"),
+                (96, 96, "crop", "image/png"),
+                (320, 240, "scale", "image/png"),
+                (640, 480, "scale", "image/png"),
+            )
+        else:
+            return ()
+
+    @defer.inlineCallbacks
+    def _generate_local_thumbnails(self, media_id, media_info):
+        media_type = media_info["media_type"]
+        requirements = self._get_thumbnail_requirements(media_type)
+        if not requirements:
+            return
+
+        input_path = self.filepaths.local_media_filepath(media_id)
+        thumbnailer = Thumbnailer(input_path)
+        m_width = thumbnailer.width
+        m_height = thumbnailer.height
+
+        if m_width * m_height >= self.max_image_pixels:
+            logger.info(
+                "Image too large to thumbnail %r x %r > %r",
+                m_width, m_height, self.max_image_pixels
+            )
+            return
+
+        scales = set()
+        crops = set()
+        for r_width, r_height, r_method, r_type in requirements:
+            if r_method == "scale":
+                t_width, t_height = thumbnailer.aspect(r_width, r_height)
+                scales.add((
+                    min(m_width, t_width), min(m_height, t_height), r_type,
+                ))
+            elif r_method == "crop":
+                crops.add((r_width, r_height, r_type))
+
+        for t_width, t_height, t_type in scales:
+            t_method = "scale"
+            t_path = self.filepaths.local_media_thumbnail(
+                media_id, t_width, t_height, t_type, t_method
+            )
+            self._makedirs(t_path)
+            t_len = thumbnailer.scale(t_path, t_width, t_height, t_type)
+            yield self.store.store_local_thumbnail(
+                media_id, t_width, t_height, t_type, t_method, t_len
+            )
+
+        for t_width, t_height, t_type in crops:
+            if (t_width, t_height, t_type) in scales:
+                # If the aspect ratio of the cropped thumbnail matches a purely
+                # scaled one then there is no point in calculating a separate
+                # thumbnail.
+                continue
+            t_method = "crop"
+            t_path = self.filepaths.local_media_thumbnail(
+                media_id, t_width, t_height, t_type, t_method
+            )
+            self._makedirs(t_path)
+            t_len = thumbnailer.crop(t_path, t_width, t_height, t_type)
+            yield self.store.store_local_thumbnail(
+                media_id, t_width, t_height, t_type, t_method, t_len
+            )
+
+        defer.returnValue({
+            "width": m_width,
+            "height": m_height,
+        })
+
+    @defer.inlineCallbacks
+    def _generate_remote_thumbnails(self, server_name, media_id, media_info):
+        media_type = media_info["media_type"]
+        file_id = media_info["filesystem_id"]
+        requirements = self._get_thumbnail_requirements(media_type)
+        if not requirements:
+            return
+
+        input_path = self.filepaths.remote_media_filepath(server_name, file_id)
+        thumbnailer = Thumbnailer(input_path)
+        m_width = thumbnailer.width
+        m_height = thumbnailer.height
+
+        if m_width * m_height >= self.max_image_pixels:
+            logger.info(
+                "Image too large to thumbnail %r x %r > %r",
+                m_width, m_height, self.max_image_pixels
+            )
+            return
+
+        scales = set()
+        crops = set()
+        for r_width, r_height, r_method, r_type in requirements:
+            if r_method == "scale":
+                t_width, t_height = thumbnailer.aspect(r_width, r_height)
+                scales.add((
+                    min(m_width, t_width), min(m_height, t_height), r_type,
+                ))
+            elif r_method == "crop":
+                crops.add((r_width, r_height, r_type))
+
+        for t_width, t_height, t_type in scales:
+            t_method = "scale"
+            t_path = self.filepaths.remote_media_thumbnail(
+                server_name, file_id, t_width, t_height, t_type, t_method
+            )
+            self._makedirs(t_path)
+            t_len = thumbnailer.scale(t_path, t_width, t_height, t_type)
+            yield self.store.store_remote_media_thumbnail(
+                server_name, media_id, file_id,
+                t_width, t_height, t_type, t_method, t_len
+            )
+
+        for t_width, t_height, t_type in crops:
+            if (t_width, t_height, t_type) in scales:
+                # If the aspect ratio of the cropped thumbnail matches a purely
+                # scaled one then there is no point in calculating a separate
+                # thumbnail.
+                continue
+            t_method = "crop"
+            t_path = self.filepaths.remote_media_thumbnail(
+                server_name, file_id, t_width, t_height, t_type, t_method
+            )
+            self._makedirs(t_path)
+            t_len = thumbnailer.crop(t_path, t_width, t_height, t_type)
+            yield self.store.store_remote_media_thumbnail(
+                server_name, media_id, file_id,
+                t_width, t_height, t_type, t_method, t_len
+            )
+
+        defer.returnValue({
+            "width": m_width,
+            "height": m_height,
+        })
diff --git a/synapse/media/v1/download_resource.py b/synapse/media/v1/download_resource.py
new file mode 100644
index 0000000000..f3a6804e05
--- /dev/null
+++ b/synapse/media/v1/download_resource.py
@@ -0,0 +1,68 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .base_resource import BaseMediaResource
+
+from twisted.web.server import NOT_DONE_YET
+from twisted.internet import defer
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class DownloadResource(BaseMediaResource):
+    def render_GET(self, request):
+        self._async_render_GET(request)
+        return NOT_DONE_YET
+
+    @BaseMediaResource.catch_errors
+    @defer.inlineCallbacks
+    def _async_render_GET(self, request):
+        try:
+            server_name, media_id = request.postpath
+        except:
+            self._respond_404(request)
+            return
+
+        if server_name == self.server_name:
+            yield self._respond_local_file(request, media_id)
+        else:
+            yield self._respond_remote_file(request, server_name, media_id)
+
+    @defer.inlineCallbacks
+    def _respond_local_file(self, request, media_id):
+        media_info = yield self.store.get_local_media(media_id)
+        if not media_info:
+            self._respond_404()
+            return
+
+        media_type = media_info["media_type"]
+        file_path = self.filepaths.local_media_filepath(media_id)
+
+        yield self._respond_with_file(request, media_type, file_path)
+
+    @defer.inlineCallbacks
+    def _respond_remote_file(self, request, server_name, media_id):
+        media_info = yield self._get_remote_media(server_name, media_id)
+
+        media_type = media_info["media_type"]
+        filesystem_id = media_info["filesystem_id"]
+
+        file_path = self.filepaths.remote_media_filepath(
+            server_name, filesystem_id
+        )
+
+        yield self._respond_with_file(request, media_type, file_path)
diff --git a/synapse/media/v1/filepath.py b/synapse/media/v1/filepath.py
new file mode 100644
index 0000000000..0078bc3d40
--- /dev/null
+++ b/synapse/media/v1/filepath.py
@@ -0,0 +1,67 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+
+
+class MediaFilePaths(object):
+
+    def __init__(self, base_path):
+        self.base_path = base_path
+
+    def default_thumbnail(self, default_top_level, default_sub_type, width,
+                          height, content_type, method):
+        top_level_type, sub_type = content_type.split("/")
+        file_name = "%i-%i-%s-%s-%s" % (
+            width, height, top_level_type, sub_type, method
+        )
+        return os.path.join(
+            self.base_path, "default_thumbnails", default_top_level,
+            default_sub_type, file_name
+        )
+
+    def local_media_filepath(self, media_id):
+        return os.path.join(
+            self.base_path, "local_content",
+            media_id[0:2], media_id[2:4], media_id[4:]
+        )
+
+    def local_media_thumbnail(self, media_id, width, height, content_type,
+                              method):
+        top_level_type, sub_type = content_type.split("/")
+        file_name = "%i-%i-%s-%s-%s" % (
+            width, height, top_level_type, sub_type, method
+        )
+        return os.path.join(
+            self.base_path, "local_thumbnails",
+            media_id[0:2], media_id[2:4], media_id[4:],
+            file_name
+        )
+
+    def remote_media_filepath(self, server_name, file_id):
+        return os.path.join(
+            self.base_path, "remote_content", server_name,
+            file_id[0:2], file_id[2:4], file_id[4:]
+        )
+
+    def remote_media_thumbnail(self, server_name, file_id, width, height,
+                               content_type, method):
+        top_level_type, sub_type = content_type.split("/")
+        file_name = "%i-%i-%s-%s" % (width, height, top_level_type, sub_type)
+        return os.path.join(
+            self.base_path, "remote_thumbnail", server_name,
+            file_id[0:2], file_id[2:4], file_id[4:],
+            file_name
+        )
diff --git a/synapse/media/v1/media_repository.py b/synapse/media/v1/media_repository.py
new file mode 100644
index 0000000000..2070ec3c7f
--- /dev/null
+++ b/synapse/media/v1/media_repository.py
@@ -0,0 +1,77 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .upload_resource import UploadResource
+from .download_resource import DownloadResource
+from .thumbnail_resource import ThumbnailResource
+from .filepath import MediaFilePaths
+
+from twisted.web.resource import Resource
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class MediaRepositoryResource(Resource):
+    """File uploading and downloading.
+
+    Uploads are POSTed to a resource which returns a token which is used to GET
+    the download::
+
+        => POST /_matrix/media/v1/upload HTTP/1.1
+           Content-Type: <media-type>
+
+           <media>
+
+        <= HTTP/1.1 200 OK
+           Content-Type: application/json
+
+           { "content_uri": "mxc://<server-name>/<media-id>" }
+
+        => GET /_matrix/media/v1/download/<server-name>/<media-id> HTTP/1.1
+
+        <= HTTP/1.1 200 OK
+           Content-Type: <media-type>
+           Content-Disposition: attachment;filename=<upload-filename>
+
+           <media>
+
+    Clients can get thumbnails by supplying a desired width and height and
+    thumbnailing method::
+
+        => GET /_matrix/media/v1/thumbnail/<server_name>
+                /<media-id>?width=<w>&height=<h>&method=<m> HTTP/1.1
+
+        <= HTTP/1.1 200 OK
+           Content-Type: image/jpeg or image/png
+
+           <thumbnail>
+
+    The thumbnail methods are "crop" and "scale". "scale" trys to return an
+    image where either the width or the height is smaller than the requested
+    size. The client should then scale and letterbox the image if it needs to
+    fit within a given rectangle. "crop" trys to return an image where the
+    width and height are close to the requested size and the aspect matches
+    the requested size. The client should scale the image if it needs to fit
+    within a given rectangle.
+    """
+
+    def __init__(self, hs):
+        Resource.__init__(self)
+        filepaths = MediaFilePaths(hs.config.media_store_path)
+        self.putChild("upload", UploadResource(hs, filepaths))
+        self.putChild("download", DownloadResource(hs, filepaths))
+        self.putChild("thumbnail", ThumbnailResource(hs, filepaths))
diff --git a/synapse/media/v1/thumbnail_resource.py b/synapse/media/v1/thumbnail_resource.py
new file mode 100644
index 0000000000..e19620d456
--- /dev/null
+++ b/synapse/media/v1/thumbnail_resource.py
@@ -0,0 +1,182 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+from .base_resource import BaseMediaResource
+
+from twisted.web.server import NOT_DONE_YET
+from twisted.internet import defer
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class ThumbnailResource(BaseMediaResource):
+    isLeaf = True
+
+    def render_GET(self, request):
+        self._async_render_GET(request)
+        return NOT_DONE_YET
+
+    @BaseMediaResource.catch_errors
+    @defer.inlineCallbacks
+    def _async_render_GET(self, request):
+        server_name, media_id = self._parse_media_id(request)
+        width = self._parse_integer(request, "width")
+        height = self._parse_integer(request, "height")
+        method = self._parse_string(request, "method", "scale")
+        m_type = self._parse_string(request, "type", "image/png")
+
+        if server_name == self.server_name:
+            yield self._respond_local_thumbnail(
+                request, media_id, width, height, method, m_type
+            )
+        else:
+            yield self._respond_remote_thumbnail(
+                request, server_name, media_id,
+                width, height, method, m_type
+            )
+
+    @defer.inlineCallbacks
+    def _respond_local_thumbnail(self, request, media_id, width, height,
+                                 method, m_type):
+        media_info = yield self.store.get_local_media(media_id)
+
+        if not media_info:
+            self._respond_404(request)
+            return
+
+        thumbnail_infos = yield self.store.get_local_media_thumbnails(media_id)
+
+        if thumbnail_infos:
+            thumbnail_info = self._select_thumbnail(
+                width, height, method, m_type, thumbnail_infos
+            )
+            t_width = thumbnail_info["thumbnail_width"]
+            t_height = thumbnail_info["thumbnail_height"]
+            t_type = thumbnail_info["thumbnail_type"]
+            t_method = thumbnail_info["thumbnail_method"]
+
+            file_path = self.filepaths.local_media_thumbnail(
+                media_id, t_width, t_height, t_type, t_method,
+            )
+            yield self._respond_with_file(request, t_type, file_path)
+
+        else:
+            yield self._respond_default_thumbnail(
+                request, media_info, width, height, method, m_type,
+            )
+
+    @defer.inlineCallbacks
+    def _respond_remote_thumbnail(self, request, server_name, media_id, width,
+                                  height, method, m_type):
+        # TODO: Don't download the whole remote file
+        # We should proxy the thumbnail from the remote server instead.
+        media_info = yield self._get_remote_media(server_name, media_id)
+
+        thumbnail_infos = yield self.store.get_remote_media_thumbnails(
+            server_name, media_id,
+        )
+
+        if thumbnail_infos:
+            thumbnail_info = self._select_thumbnail(
+                width, height, method, m_type, thumbnail_infos
+            )
+            t_width = thumbnail_info["thumbnail_width"]
+            t_height = thumbnail_info["thumbnail_height"]
+            t_type = thumbnail_info["thumbnail_type"]
+            t_method = thumbnail_info["thumbnail_method"]
+            file_id = thumbnail_info["filesystem_id"]
+
+            file_path = self.filepaths.remote_media_thumbnail(
+                server_name, file_id, t_width, t_height, t_type, t_method,
+            )
+            yield self._respond_with_file(request, t_type, file_path)
+        else:
+            yield self._respond_default_thumbnail(
+                request, media_info, width, height, method, m_type,
+            )
+
+    @defer.inlineCallbacks
+    def _respond_default_thumbnail(self, request, media_info, width, height,
+                                   method, m_type):
+        media_type = media_info["media_type"]
+        top_level_type = media_type.split("/")[0]
+        sub_type = media_type.split("/")[-1].split(";")[0]
+        thumbnail_infos = yield self.store.get_default_thumbnails(
+            top_level_type, sub_type,
+        )
+        if not thumbnail_infos:
+            thumbnail_infos = yield self.store.get_default_thumbnails(
+                top_level_type, "_default",
+            )
+        if not thumbnail_infos:
+            thumbnail_infos = yield self.store.get_default_thumbnails(
+                "_default", "_default",
+            )
+        if not thumbnail_infos:
+            self._respond_404(request)
+            return
+
+        thumbnail_info = self._select_thumbnail(
+            width, height, "crop", m_type, thumbnail_infos
+        )
+
+        t_width = thumbnail_info["thumbnail_width"]
+        t_height = thumbnail_info["thumbnail_height"]
+        t_type = thumbnail_info["thumbnail_type"]
+        t_method = thumbnail_info["thumbnail_method"]
+
+        file_path = self.filepaths.default_thumbnail(
+            top_level_type, sub_type, t_width, t_height, t_type, t_method,
+        )
+        yield self.respond_with_file(request, t_type, file_path)
+
+    def _select_thumbnail(self, desired_width, desired_height, desired_method,
+                          desired_type, thumbnail_infos):
+        d_w = desired_width
+        d_h = desired_height
+
+        if desired_method.lower() == "crop":
+            info_list = []
+            for info in thumbnail_infos:
+                t_w = info["thumbnail_width"]
+                t_h = info["thumbnail_height"]
+                t_method = info["thumbnail_method"]
+                if t_method == "scale" or t_method == "crop":
+                    aspect_quality = abs(d_w * t_h - d_h * t_w)
+                    size_quality = abs((d_w - t_w) * (d_h - t_h))
+                    type_quality = desired_type != info["thumbnail_type"]
+                    length_quality = info["thumbnail_length"]
+                    info_list.append((
+                        aspect_quality, size_quality, type_quality,
+                        length_quality, info
+                    ))
+            return min(info_list)[-1]
+        else:
+            info_list = []
+            for info in thumbnail_infos:
+                t_w = info["thumbnail_width"]
+                t_h = info["thumbnail_height"]
+                t_method = info["thumbnail_method"]
+                if t_method == "scale" and (t_w >= d_w or t_h >= d_h):
+                    size_quality = abs((d_w - t_w) * (d_h - t_h))
+                    type_quality = desired_type != info["thumbnail_type"]
+                    length_quality = info["thumbnail_length"]
+                    info_list.append((
+                        size_quality, type_quality, length_quality, info
+                    ))
+            return min(info_list)[-1]
diff --git a/synapse/media/v1/thumbnailer.py b/synapse/media/v1/thumbnailer.py
new file mode 100644
index 0000000000..774ae4538f
--- /dev/null
+++ b/synapse/media/v1/thumbnailer.py
@@ -0,0 +1,89 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import PIL.Image as Image
+from io import BytesIO
+
+
+class Thumbnailer(object):
+
+    FORMATS = {
+        "image/jpeg": "JPEG",
+        "image/png": "PNG",
+    }
+
+    def __init__(self, input_path):
+        self.image = Image.open(input_path)
+        self.width, self.height = self.image.size
+
+    def aspect(self, max_width, max_height):
+        """Calculate the largest size that preserves aspect ratio which
+        fits within the given rectangle::
+
+            (w_in / h_in) = (w_out / h_out)
+            w_out = min(w_max, h_max * (w_in / h_in))
+            h_out = min(h_max, w_max * (h_in / w_in))
+
+        Args:
+            max_width: The largest possible width.
+            max_height: The larget possible height.
+        """
+
+        if max_width * self.height < max_height * self.width:
+            return (max_width, (max_width * self.height) // self.width)
+        else:
+            return ((max_height * self.width) // self.height, max_height)
+
+    def scale(self, output_path, width, height, output_type):
+        """Rescales the image to the given dimensions"""
+        scaled = self.image.resize((width, height), Image.BILINEAR)
+        return self.save_image(scaled, output_type, output_path)
+
+    def crop(self, output_path, width, height, output_type):
+        """Rescales and crops the image to the given dimensions preserving
+        aspect::
+            (w_in / h_in) = (w_scaled / h_scaled)
+            w_scaled = max(w_out, h_out * (w_in / h_in))
+            h_scaled = max(h_out, w_out * (h_in / w_in))
+
+        Args:
+            max_width: The largest possible width.
+            max_height: The larget possible height.
+        """
+        if width * self.height > height * self.width:
+            scaled_height = (width * self.height) // self.width
+            scaled_image = self.image.resize(
+                (width, scaled_height), Image.BILINEAR
+            )
+            crop_top = (scaled_height - height) // 2
+            crop_bottom = height + crop_top
+            cropped = scaled_image.crop((0, crop_top, width, crop_bottom))
+        else:
+            scaled_width = (height * self.width) // self.height
+            scaled_image = self.image.resize(
+                (scaled_width, height), Image.BILINEAR
+            )
+            crop_left = (scaled_width - width) // 2
+            crop_right = width + crop_left
+            cropped = scaled_image.crop((crop_left, 0, crop_right, height))
+        return self.save_image(cropped, output_type, output_path)
+
+    def save_image(self, output_image, output_type, output_path):
+        output_bytes_io = BytesIO()
+        output_image.save(output_bytes_io, self.FORMATS[output_type])
+        output_bytes = output_bytes_io.getvalue()
+        with open(output_path, "wb") as output_file:
+            output_file.write(output_bytes)
+        return len(output_bytes)
diff --git a/synapse/media/v1/upload_resource.py b/synapse/media/v1/upload_resource.py
new file mode 100644
index 0000000000..5645b0df46
--- /dev/null
+++ b/synapse/media/v1/upload_resource.py
@@ -0,0 +1,113 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from synapse.http.server import respond_with_json
+
+from synapse.util.stringutils import random_string
+from synapse.api.errors import (
+    cs_exception, SynapseError, CodeMessageException
+)
+
+from twisted.web.server import NOT_DONE_YET
+from twisted.internet import defer
+
+from .base_resource import BaseMediaResource
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class UploadResource(BaseMediaResource):
+    def render_POST(self, request):
+        self._async_render_POST(request)
+        return NOT_DONE_YET
+
+    def render_OPTIONS(self, request):
+        respond_with_json(request, 200, {}, send_cors=True)
+        return NOT_DONE_YET
+
+    @defer.inlineCallbacks
+    def _async_render_POST(self, request):
+        try:
+            auth_user = yield self.auth.get_user_by_req(request)
+            # TODO: The checks here are a bit late. The content will have
+            # already been uploaded to a tmp file at this point
+            content_length = request.getHeader("Content-Length")
+            if content_length is None:
+                raise SynapseError(
+                    msg="Request must specify a Content-Length", code=400
+                )
+            if int(content_length) > self.max_upload_size:
+                raise SynapseError(
+                    msg="Upload request body is too large",
+                    code=413,
+                )
+
+            headers = request.requestHeaders
+
+            if headers.hasHeader("Content-Type"):
+                media_type = headers.getRawHeaders("Content-Type")[0]
+            else:
+                raise SynapseError(
+                    msg="Upload request missing 'Content-Type'",
+                    code=400,
+                )
+
+            #if headers.hasHeader("Content-Disposition"):
+            #    disposition = headers.getRawHeaders("Content-Disposition")[0]
+            # TODO(markjh): parse content-dispostion
+
+            media_id = random_string(24)
+
+            fname = self.filepaths.local_media_filepath(media_id)
+            self._makedirs(fname)
+
+            # This shouldn't block for very long because the content will have
+            # already been uploaded at this point.
+            with open(fname, "wb") as f:
+                f.write(request.content.read())
+
+            yield self.store.store_local_media(
+                media_id=media_id,
+                media_type=media_type,
+                time_now_ms=self.clock.time_msec(),
+                upload_name=None,
+                media_length=content_length,
+                user_id=auth_user,
+            )
+            media_info = {
+                "media_type": media_type,
+                "media_length": content_length,
+            }
+
+            yield self._generate_local_thumbnails(media_id, media_info)
+
+            content_uri = "mxc://%s/%s" % (self.server_name, media_id)
+
+            respond_with_json(
+                request, 200, {"content_uri": content_uri}, send_cors=True
+            )
+        except CodeMessageException as e:
+            logger.exception(e)
+            respond_with_json(request, e.code, cs_exception(e), send_cors=True)
+        except:
+            logger.exception("Failed to store file")
+            respond_with_json(
+                request,
+                500,
+                {"error": "Internal server error"},
+                send_cors=True
+            )
diff --git a/synapse/notifier.py b/synapse/notifier.py
index 5e14950449..383230caf1 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -146,7 +146,11 @@ class Notifier(object):
         Will wake up all listeners for the given users and rooms.
         """
         yield run_on_reactor()
+
+        # TODO(paul): This is horrible, having to manually list every event
+        # source here individually
         presence_source = self.event_sources.sources["presence"]
+        typing_source = self.event_sources.sources["typing"]
 
         listeners = set()
 
@@ -158,19 +162,33 @@ class Notifier(object):
 
         @defer.inlineCallbacks
         def notify(listener):
-            events, end_key = yield presence_source.get_new_events_for_user(
-                listener.user,
-                listener.from_token.presence_key,
-                listener.limit,
+            presence_events, presence_end_key = (
+                yield presence_source.get_new_events_for_user(
+                    listener.user,
+                    listener.from_token.presence_key,
+                    listener.limit,
+                )
+            )
+            typing_events, typing_end_key = (
+                yield typing_source.get_new_events_for_user(
+                    listener.user,
+                    listener.from_token.typing_key,
+                    listener.limit,
+                )
             )
 
-            if events:
+            if presence_events or typing_events:
                 end_token = listener.from_token.copy_and_replace(
-                    "presence_key", end_key
+                    "presence_key", presence_end_key
+                ).copy_and_replace(
+                    "typing_key", typing_end_key
                 )
 
                 listener.notify(
-                    self, events, listener.from_token, end_token
+                    self,
+                    presence_events + typing_events,
+                    listener.from_token,
+                    end_token
                 )
 
         def eb(failure):
diff --git a/synapse/rest/__init__.py b/synapse/rest/__init__.py
index c38cf27690..c29896bde9 100644
--- a/synapse/rest/__init__.py
+++ b/synapse/rest/__init__.py
@@ -28,7 +28,7 @@ class RestServletFactory(object):
     speaking, they serve as wrappers around events and the handlers that
     process them.
 
-    See synapse.api.events for information on synapse events.
+    See synapse.events for information on synapse events.
     """
 
     def __init__(self, hs):
diff --git a/synapse/rest/admin.py b/synapse/rest/admin.py
index ed9b484623..d74c551512 100644
--- a/synapse/rest/admin.py
+++ b/synapse/rest/admin.py
@@ -35,7 +35,7 @@ class WhoisRestServlet(RestServlet):
         if not is_admin and target_user != auth_user:
             raise AuthError(403, "You are not a server admin")
 
-        if not target_user.is_mine:
+        if not self.hs.is_mine(target_user):
             raise SynapseError(400, "Can only whois a local user")
 
         ret = yield self.handlers.admin_handler.get_whois(target_user)
diff --git a/synapse/rest/base.py b/synapse/rest/base.py
index 79fc4dfb84..06eda2587c 100644
--- a/synapse/rest/base.py
+++ b/synapse/rest/base.py
@@ -63,12 +63,10 @@ class RestServlet(object):
         self.hs = hs
 
         self.handlers = hs.get_handlers()
-        self.event_factory = hs.get_event_factory()
+        self.builder_factory = hs.get_event_builder_factory()
         self.auth = hs.get_auth()
         self.txns = HttpTransactionStore()
 
-        self.validator = hs.get_event_validator()
-
     def register(self, http_server):
         """ Register this servlet with the given HTTP server. """
         if hasattr(self, "PATTERN"):
diff --git a/synapse/rest/directory.py b/synapse/rest/directory.py
index 35300c6a6f..868fa7abed 100644
--- a/synapse/rest/directory.py
+++ b/synapse/rest/directory.py
@@ -21,7 +21,6 @@ from base import RestServlet, client_path_pattern
 
 import json
 import logging
-import urllib
 
 
 logger = logging.getLogger(__name__)
@@ -36,9 +35,7 @@ class ClientDirectoryServer(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, room_alias):
-        room_alias = self.hs.parse_roomalias(
-            urllib.unquote(room_alias).decode("utf-8")
-        )
+        room_alias = self.hs.parse_roomalias(room_alias)
 
         dir_handler = self.handlers.directory_handler
         res = yield dir_handler.get_association(room_alias)
@@ -56,9 +53,7 @@ class ClientDirectoryServer(RestServlet):
 
         logger.debug("Got content: %s", content)
 
-        room_alias = self.hs.parse_roomalias(
-            urllib.unquote(room_alias).decode("utf-8")
-        )
+        room_alias = self.hs.parse_roomalias(room_alias)
 
         logger.debug("Got room name: %s", room_alias.to_string())
 
@@ -97,9 +92,7 @@ class ClientDirectoryServer(RestServlet):
 
         dir_handler = self.handlers.directory_handler
 
-        room_alias = self.hs.parse_roomalias(
-            urllib.unquote(room_alias).decode("utf-8")
-        )
+        room_alias = self.hs.parse_roomalias(room_alias)
 
         yield dir_handler.delete_association(
             user.to_string(), room_alias
diff --git a/synapse/rest/login.py b/synapse/rest/login.py
index ad71f6c61d..875da076af 100644
--- a/synapse/rest/login.py
+++ b/synapse/rest/login.py
@@ -47,8 +47,8 @@ class LoginRestServlet(RestServlet):
     @defer.inlineCallbacks
     def do_password_login(self, login_submission):
         if not login_submission["user"].startswith('@'):
-            login_submission["user"] = UserID.create_local(
-                login_submission["user"], self.hs).to_string()
+            login_submission["user"] = UserID.create(
+                login_submission["user"], self.hs.hostname).to_string()
 
         handler = self.handlers.login_handler
         token = yield handler.login(
diff --git a/synapse/rest/presence.py b/synapse/rest/presence.py
index 502ed0d4ca..9b42131628 100644
--- a/synapse/rest/presence.py
+++ b/synapse/rest/presence.py
@@ -22,7 +22,6 @@ from base import RestServlet, client_path_pattern
 
 import json
 import logging
-import urllib
 
 logger = logging.getLogger(__name__)
 
@@ -33,7 +32,6 @@ class PresenceStatusRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_GET(self, request, user_id):
         auth_user = yield self.auth.get_user_by_req(request)
-        user_id = urllib.unquote(user_id)
         user = self.hs.parse_userid(user_id)
 
         state = yield self.handlers.presence_handler.get_state(
@@ -44,7 +42,6 @@ class PresenceStatusRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_PUT(self, request, user_id):
         auth_user = yield self.auth.get_user_by_req(request)
-        user_id = urllib.unquote(user_id)
         user = self.hs.parse_userid(user_id)
 
         state = {}
@@ -80,10 +77,9 @@ class PresenceListRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_GET(self, request, user_id):
         auth_user = yield self.auth.get_user_by_req(request)
-        user_id = urllib.unquote(user_id)
         user = self.hs.parse_userid(user_id)
 
-        if not user.is_mine:
+        if not self.hs.is_mine(user):
             raise SynapseError(400, "User not hosted on this Home Server")
 
         if auth_user != user:
@@ -101,10 +97,9 @@ class PresenceListRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_POST(self, request, user_id):
         auth_user = yield self.auth.get_user_by_req(request)
-        user_id = urllib.unquote(user_id)
         user = self.hs.parse_userid(user_id)
 
-        if not user.is_mine:
+        if not self.hs.is_mine(user):
             raise SynapseError(400, "User not hosted on this Home Server")
 
         if auth_user != user:
diff --git a/synapse/rest/profile.py b/synapse/rest/profile.py
index 72e02d8dd8..351863ab5d 100644
--- a/synapse/rest/profile.py
+++ b/synapse/rest/profile.py
@@ -19,7 +19,6 @@ from twisted.internet import defer
 from base import RestServlet, client_path_pattern
 
 import json
-import urllib
 
 
 class ProfileDisplaynameRestServlet(RestServlet):
@@ -27,7 +26,6 @@ class ProfileDisplaynameRestServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, user_id):
-        user_id = urllib.unquote(user_id)
         user = self.hs.parse_userid(user_id)
 
         displayname = yield self.handlers.profile_handler.get_displayname(
@@ -39,7 +37,6 @@ class ProfileDisplaynameRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_PUT(self, request, user_id):
         auth_user = yield self.auth.get_user_by_req(request)
-        user_id = urllib.unquote(user_id)
         user = self.hs.parse_userid(user_id)
 
         try:
@@ -62,7 +59,6 @@ class ProfileAvatarURLRestServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, user_id):
-        user_id = urllib.unquote(user_id)
         user = self.hs.parse_userid(user_id)
 
         avatar_url = yield self.handlers.profile_handler.get_avatar_url(
@@ -74,7 +70,6 @@ class ProfileAvatarURLRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_PUT(self, request, user_id):
         auth_user = yield self.auth.get_user_by_req(request)
-        user_id = urllib.unquote(user_id)
         user = self.hs.parse_userid(user_id)
 
         try:
@@ -97,7 +92,6 @@ class ProfileRestServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, user_id):
-        user_id = urllib.unquote(user_id)
         user = self.hs.parse_userid(user_id)
 
         displayname = yield self.handlers.profile_handler.get_displayname(
diff --git a/synapse/rest/register.py b/synapse/rest/register.py
index f25e23a158..4f0f5a7531 100644
--- a/synapse/rest/register.py
+++ b/synapse/rest/register.py
@@ -21,6 +21,8 @@ from synapse.api.constants import LoginType
 from base import RestServlet, client_path_pattern
 import synapse.util.stringutils as stringutils
 
+from synapse.util.async import run_on_reactor
+
 from hashlib import sha1
 import hmac
 import json
@@ -233,7 +235,7 @@ class RegisterRestServlet(RestServlet):
 
     @defer.inlineCallbacks
     def _do_password(self, request, register_json, session):
-        yield
+        yield run_on_reactor()
         if (self.hs.config.enable_registration_captcha and
                 not session[LoginType.RECAPTCHA]):
             # captcha should've been done by this stage!
diff --git a/synapse/rest/room.py b/synapse/rest/room.py
index 3147d7a60b..005a9f6f44 100644
--- a/synapse/rest/room.py
+++ b/synapse/rest/room.py
@@ -19,8 +19,7 @@ from twisted.internet import defer
 from base import RestServlet, client_path_pattern
 from synapse.api.errors import SynapseError, Codes
 from synapse.streams.config import PaginationConfig
-from synapse.api.events.room import RoomMemberEvent, RoomRedactionEvent
-from synapse.api.constants import Membership
+from synapse.api.constants import EventTypes, Membership
 
 import json
 import logging
@@ -129,9 +128,9 @@ class RoomStateEventRestServlet(RestServlet):
         msg_handler = self.handlers.message_handler
         data = yield msg_handler.get_room_data(
             user_id=user.to_string(),
-            room_id=urllib.unquote(room_id),
-            event_type=urllib.unquote(event_type),
-            state_key=urllib.unquote(state_key),
+            room_id=room_id,
+            event_type=event_type,
+            state_key=state_key,
         )
 
         if not data:
@@ -143,32 +142,23 @@ class RoomStateEventRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_PUT(self, request, room_id, event_type, state_key):
         user = yield self.auth.get_user_by_req(request)
-        event_type = urllib.unquote(event_type)
 
         content = _parse_json(request)
 
-        event = self.event_factory.create_event(
-            etype=event_type,  # already urldecoded
-            content=content,
-            room_id=urllib.unquote(room_id),
-            user_id=user.to_string(),
-            state_key=urllib.unquote(state_key)
-            )
+        event_dict = {
+            "type": event_type,
+            "content": content,
+            "room_id": room_id,
+            "sender": user.to_string(),
+        }
 
-        self.validator.validate(event)
+        if state_key is not None:
+            event_dict["state_key"] = state_key
 
-        if event_type == RoomMemberEvent.TYPE:
-            # membership events are special
-            handler = self.handlers.room_member_handler
-            yield handler.change_membership(event)
-            defer.returnValue((200, {}))
-        else:
-            # store random bits of state
-            msg_handler = self.handlers.message_handler
-            yield msg_handler.store_room_data(
-                event=event
-            )
-            defer.returnValue((200, {}))
+        msg_handler = self.handlers.message_handler
+        yield msg_handler.create_and_send_event(event_dict)
+
+        defer.returnValue((200, {}))
 
 
 # TODO: Needs unit testing for generic events + feedback
@@ -184,17 +174,15 @@ class RoomSendEventRestServlet(RestServlet):
         user = yield self.auth.get_user_by_req(request)
         content = _parse_json(request)
 
-        event = self.event_factory.create_event(
-            etype=urllib.unquote(event_type),
-            room_id=urllib.unquote(room_id),
-            user_id=user.to_string(),
-            content=content
-        )
-
-        self.validator.validate(event)
-
         msg_handler = self.handlers.message_handler
-        yield msg_handler.send_message(event)
+        event = yield msg_handler.create_and_send_event(
+            {
+                "type": event_type,
+                "content": content,
+                "room_id": room_id,
+                "sender": user.to_string(),
+            }
+        )
 
         defer.returnValue((200, {"event_id": event.event_id}))
 
@@ -235,14 +223,10 @@ class JoinRoomAliasServlet(RestServlet):
         identifier = None
         is_room_alias = False
         try:
-            identifier = self.hs.parse_roomalias(
-                urllib.unquote(room_identifier)
-            )
+            identifier = self.hs.parse_roomalias(room_identifier)
             is_room_alias = True
         except SynapseError:
-            identifier = self.hs.parse_roomid(
-                urllib.unquote(room_identifier)
-            )
+            identifier = self.hs.parse_roomid(room_identifier)
 
         # TODO: Support for specifying the home server to join with?
 
@@ -251,18 +235,17 @@ class JoinRoomAliasServlet(RestServlet):
             ret_dict = yield handler.join_room_alias(user, identifier)
             defer.returnValue((200, ret_dict))
         else:  # room id
-            event = self.event_factory.create_event(
-                etype=RoomMemberEvent.TYPE,
-                content={"membership": Membership.JOIN},
-                room_id=urllib.unquote(identifier.to_string()),
-                user_id=user.to_string(),
-                state_key=user.to_string()
+            msg_handler = self.handlers.message_handler
+            yield msg_handler.create_and_send_event(
+                {
+                    "type": EventTypes.Member,
+                    "content": {"membership": Membership.JOIN},
+                    "room_id": identifier.to_string(),
+                    "sender": user.to_string(),
+                    "state_key": user.to_string(),
+                }
             )
 
-            self.validator.validate(event)
-
-            handler = self.handlers.room_member_handler
-            yield handler.change_membership(event)
             defer.returnValue((200, {}))
 
     @defer.inlineCallbacks
@@ -301,7 +284,7 @@ class RoomMemberListRestServlet(RestServlet):
         user = yield self.auth.get_user_by_req(request)
         handler = self.handlers.room_member_handler
         members = yield handler.get_room_members_as_pagination_chunk(
-            room_id=urllib.unquote(room_id),
+            room_id=room_id,
             user_id=user.to_string())
 
         for event in members["chunk"]:
@@ -327,13 +310,13 @@ class RoomMessageListRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_GET(self, request, room_id):
         user = yield self.auth.get_user_by_req(request)
-        pagination_config = PaginationConfig.from_request(request,
-            default_limit=10,
+        pagination_config = PaginationConfig.from_request(
+            request, default_limit=10,
         )
         with_feedback = "feedback" in request.args
         handler = self.handlers.message_handler
         msgs = yield handler.get_messages(
-            room_id=urllib.unquote(room_id),
+            room_id=room_id,
             user_id=user.to_string(),
             pagin_config=pagination_config,
             feedback=with_feedback)
@@ -351,7 +334,7 @@ class RoomStateRestServlet(RestServlet):
         handler = self.handlers.message_handler
         # Get all the current state for this room
         events = yield handler.get_state_events(
-            room_id=urllib.unquote(room_id),
+            room_id=room_id,
             user_id=user.to_string(),
         )
         defer.returnValue((200, events))
@@ -366,7 +349,7 @@ class RoomInitialSyncRestServlet(RestServlet):
         user = yield self.auth.get_user_by_req(request)
         pagination_config = PaginationConfig.from_request(request)
         content = yield self.handlers.message_handler.room_initial_sync(
-            room_id=urllib.unquote(room_id),
+            room_id=room_id,
             user_id=user.to_string(),
             pagin_config=pagination_config,
         )
@@ -378,8 +361,10 @@ class RoomTriggerBackfill(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, room_id):
-        remote_server = urllib.unquote(request.args["remote"][0])
-        room_id = urllib.unquote(room_id)
+        remote_server = urllib.unquote(
+            request.args["remote"][0]
+        ).decode("UTF-8")
+
         limit = int(request.args["limit"][0])
 
         handler = self.handlers.federation_handler
@@ -414,18 +399,17 @@ class RoomMembershipRestServlet(RestServlet):
             if membership_action == "kick":
                 membership_action = "leave"
 
-        event = self.event_factory.create_event(
-            etype=RoomMemberEvent.TYPE,
-            content={"membership": unicode(membership_action)},
-            room_id=urllib.unquote(room_id),
-            user_id=user.to_string(),
-            state_key=state_key
+        msg_handler = self.handlers.message_handler
+        yield msg_handler.create_and_send_event(
+            {
+                "type": EventTypes.Member,
+                "content": {"membership": unicode(membership_action)},
+                "room_id": room_id,
+                "sender": user.to_string(),
+                "state_key": state_key,
+            }
         )
 
-        self.validator.validate(event)
-
-        handler = self.handlers.room_member_handler
-        yield handler.change_membership(event)
         defer.returnValue((200, {}))
 
     @defer.inlineCallbacks
@@ -453,18 +437,16 @@ class RoomRedactEventRestServlet(RestServlet):
         user = yield self.auth.get_user_by_req(request)
         content = _parse_json(request)
 
-        event = self.event_factory.create_event(
-            etype=RoomRedactionEvent.TYPE,
-            room_id=urllib.unquote(room_id),
-            user_id=user.to_string(),
-            content=content,
-            redacts=urllib.unquote(event_id),
-        )
-
-        self.validator.validate(event)
-
         msg_handler = self.handlers.message_handler
-        yield msg_handler.send_message(event)
+        event = yield msg_handler.create_and_send_event(
+            {
+                "type": EventTypes.Redaction,
+                "content": content,
+                "room_id": room_id,
+                "sender": user.to_string(),
+                "redacts": event_id,
+            }
+        )
 
         defer.returnValue((200, {"event_id": event.event_id}))
 
@@ -483,6 +465,39 @@ class RoomRedactEventRestServlet(RestServlet):
         defer.returnValue(response)
 
 
+class RoomTypingRestServlet(RestServlet):
+    PATTERN = client_path_pattern(
+        "/rooms/(?P<room_id>[^/]*)/typing/(?P<user_id>[^/]*)$"
+    )
+
+    @defer.inlineCallbacks
+    def on_PUT(self, request, room_id, user_id):
+        auth_user = yield self.auth.get_user_by_req(request)
+
+        room_id = urllib.unquote(room_id)
+        target_user = self.hs.parse_userid(urllib.unquote(user_id))
+
+        content = _parse_json(request)
+
+        typing_handler = self.handlers.typing_notification_handler
+
+        if content["typing"]:
+            yield typing_handler.started_typing(
+                target_user=target_user,
+                auth_user=auth_user,
+                room_id=room_id,
+                timeout=content.get("timeout", 30000),
+            )
+        else:
+            yield typing_handler.stopped_typing(
+                target_user=target_user,
+                auth_user=auth_user,
+                room_id=room_id,
+            )
+
+        defer.returnValue((200, {}))
+
+
 def _parse_json(request):
     try:
         content = json.loads(request.content.read())
@@ -538,3 +553,4 @@ def register_servlets(hs, http_server):
     RoomStateRestServlet(hs).register(http_server)
     RoomInitialSyncRestServlet(hs).register(http_server)
     RoomRedactEventRestServlet(hs).register(http_server)
+    RoomTypingRestServlet(hs).register(http_server)
diff --git a/synapse/rest/transactions.py b/synapse/rest/transactions.py
index 93c0122f30..31377bd41d 100644
--- a/synapse/rest/transactions.py
+++ b/synapse/rest/transactions.py
@@ -20,6 +20,7 @@ import logging
 logger = logging.getLogger(__name__)
 
 
+# FIXME: elsewhere we use FooStore to indicate something in the storage layer...
 class HttpTransactionStore(object):
 
     def __init__(self):
diff --git a/synapse/server.py b/synapse/server.py
index cfbe7d5e38..b7d6811449 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -20,9 +20,7 @@
 
 # Imports required for the default HomeServer() implementation
 from synapse.federation import initialize_http_replication
-from synapse.api.events import serialize_event
-from synapse.api.events.factory import EventFactory
-from synapse.api.events.validator import EventValidator
+from synapse.events.utils import serialize_event
 from synapse.notifier import Notifier
 from synapse.api.auth import Auth
 from synapse.handlers import Handlers
@@ -37,6 +35,7 @@ from synapse.streams.events import EventSources
 from synapse.api.ratelimiting import Ratelimiter
 from synapse.crypto.keyring import Keyring
 from synapse.push.pusherpool import PusherPool
+from synapse.events.builder import EventBuilderFactory
 
 
 class BaseHomeServer(object):
@@ -66,7 +65,6 @@ class BaseHomeServer(object):
         'persistence_service',
         'replication_layer',
         'datastore',
-        'event_factory',
         'handlers',
         'auth',
         'rest_servlet_factory',
@@ -79,11 +77,12 @@ class BaseHomeServer(object):
         'resource_for_web_client',
         'resource_for_content_repo',
         'resource_for_server_key',
+        'resource_for_media_repository',
         'event_sources',
         'ratelimiter',
         'keyring',
-        'event_validator',
-        'pusherpool'
+        'pusherpool',
+        'event_builder_factory',
     ]
 
     def __init__(self, hostname, **kwargs):
@@ -135,22 +134,22 @@ class BaseHomeServer(object):
     def parse_userid(self, s):
         """Parse the string given by 's' as a User ID and return a UserID
         object."""
-        return UserID.from_string(s, hs=self)
+        return UserID.from_string(s)
 
     def parse_roomalias(self, s):
         """Parse the string given by 's' as a Room Alias and return a RoomAlias
         object."""
-        return RoomAlias.from_string(s, hs=self)
+        return RoomAlias.from_string(s)
 
     def parse_roomid(self, s):
         """Parse the string given by 's' as a Room ID and return a RoomID
         object."""
-        return RoomID.from_string(s, hs=self)
+        return RoomID.from_string(s)
 
     def parse_eventid(self, s):
         """Parse the string given by 's' as a Event ID and return a EventID
         object."""
-        return EventID.from_string(s, hs=self)
+        return EventID.from_string(s)
 
     def serialize_event(self, e):
         return serialize_event(self, e)
@@ -167,6 +166,9 @@ class BaseHomeServer(object):
 
         return ip_addr
 
+    def is_mine(self, domain_specific_string):
+        return domain_specific_string.domain == self.hostname
+
 # Build magic accessors for every dependency
 for depname in BaseHomeServer.DEPENDENCIES:
     BaseHomeServer._make_dependency_method(depname)
@@ -194,9 +196,6 @@ class HomeServer(BaseHomeServer):
     def build_datastore(self):
         return DataStore(self)
 
-    def build_event_factory(self):
-        return EventFactory(self)
-
     def build_handlers(self):
         return Handlers(self)
 
@@ -227,8 +226,11 @@ class HomeServer(BaseHomeServer):
     def build_keyring(self):
         return Keyring(self)
 
-    def build_event_validator(self):
-        return EventValidator(self)
+    def build_event_builder_factory(self):
+        return EventBuilderFactory(
+            clock=self.get_clock(),
+            hostname=self.hostname,
+        )
 
     def build_pusherpool(self):
         return PusherPool(self)
diff --git a/synapse/state.py b/synapse/state.py
index 430665f7ba..15397e2f38 100644
--- a/synapse/state.py
+++ b/synapse/state.py
@@ -18,11 +18,11 @@ from twisted.internet import defer
 
 from synapse.util.logutils import log_function
 from synapse.util.async import run_on_reactor
-from synapse.api.events.room import RoomPowerLevelsEvent
+from synapse.api.constants import EventTypes
+from synapse.events.snapshot import EventContext
 
 from collections import namedtuple
 
-import copy
 import logging
 import hashlib
 
@@ -44,71 +44,6 @@ class StateHandler(object):
         self.store = hs.get_datastore()
 
     @defer.inlineCallbacks
-    @log_function
-    def annotate_event_with_state(self, event, old_state=None):
-        """ Annotates the event with the current state events as of that event.
-
-        This method adds three new attributes to the event:
-            * `state_events`: The state up to and including the event. Encoded
-              as a dict mapping tuple (type, state_key) -> event.
-            * `old_state_events`: The state up to, but excluding, the event.
-              Encoded similarly as `state_events`.
-            * `state_group`: If there is an existing state group that can be
-              used, then return that. Otherwise return `None`. See state
-              storage for more information.
-
-        If the argument `old_state` is given (in the form of a list of
-        events), then they are used as a the values for `old_state_events` and
-        the value for `state_events` is generated from it. `state_group` is
-        set to None.
-
-        This needs to be called before persisting the event.
-        """
-        yield run_on_reactor()
-
-        if old_state:
-            event.state_group = None
-            event.old_state_events = {
-                (s.type, s.state_key): s for s in old_state
-            }
-            event.state_events = event.old_state_events
-
-            if hasattr(event, "state_key"):
-                event.state_events[(event.type, event.state_key)] = event
-
-            defer.returnValue(False)
-            return
-
-        if hasattr(event, "outlier") and event.outlier:
-            event.state_group = None
-            event.old_state_events = None
-            event.state_events = None
-            defer.returnValue(False)
-            return
-
-        ids = [e for e, _ in event.prev_events]
-
-        ret = yield self.resolve_state_groups(ids)
-        state_group, new_state = ret
-
-        event.old_state_events = copy.deepcopy(new_state)
-
-        if hasattr(event, "state_key"):
-            key = (event.type, event.state_key)
-            if key in new_state:
-                event.replaces_state = new_state[key].event_id
-            new_state[key] = event
-        elif state_group:
-            event.state_group = state_group
-            event.state_events = new_state
-            defer.returnValue(False)
-
-        event.state_group = None
-        event.state_events = new_state
-
-        defer.returnValue(hasattr(event, "state_key"))
-
-    @defer.inlineCallbacks
     def get_current_state(self, room_id, event_type=None, state_key=""):
         """ Returns the current state for the room as a list. This is done by
         calling `get_latest_events_in_room` to get the leading edges of the
@@ -136,8 +71,91 @@ class StateHandler(object):
         defer.returnValue(res[1].values())
 
     @defer.inlineCallbacks
+    def compute_event_context(self, event, old_state=None):
+        """ Fills out the context with the `current state` of the graph. The
+        `current state` here is defined to be the state of the event graph
+        just before the event - i.e. it never includes `event`
+
+        If `event` has `auth_events` then this will also fill out the
+        `auth_events` field on `context` from the `current_state`.
+
+        Args:
+            event (EventBase)
+        Returns:
+            an EventContext
+        """
+        context = EventContext()
+
+        yield run_on_reactor()
+
+        if old_state:
+            context.current_state = {
+                (s.type, s.state_key): s for s in old_state
+            }
+            context.state_group = None
+
+            if hasattr(event, "auth_events") and event.auth_events:
+                auth_ids = zip(*event.auth_events)[0]
+                context.auth_events = {
+                    k: v
+                    for k, v in context.current_state.items()
+                    if v.event_id in auth_ids
+                }
+            else:
+                context.auth_events = {}
+
+            if event.is_state():
+                key = (event.type, event.state_key)
+                if key in context.current_state:
+                    replaces = context.current_state[key]
+                    if replaces.event_id != event.event_id:  # Paranoia check
+                        event.unsigned["replaces_state"] = replaces.event_id
+
+            context.prev_state_events = []
+            defer.returnValue(context)
+
+        if event.is_state():
+            ret = yield self.resolve_state_groups(
+                [e for e, _ in event.prev_events],
+                event_type=event.type,
+                state_key=event.state_key,
+            )
+        else:
+            ret = yield self.resolve_state_groups(
+                [e for e, _ in event.prev_events],
+            )
+
+        group, curr_state, prev_state = ret
+
+        context.current_state = curr_state
+        context.state_group = group if not event.is_state() else None
+
+        prev_state = yield self.store.add_event_hashes(
+            prev_state
+        )
+
+        if event.is_state():
+            key = (event.type, event.state_key)
+            if key in context.current_state:
+                replaces = context.current_state[key]
+                event.unsigned["replaces_state"] = replaces.event_id
+
+        if hasattr(event, "auth_events") and event.auth_events:
+            auth_ids = zip(*event.auth_events)[0]
+            context.auth_events = {
+                k: v
+                for k, v in context.current_state.items()
+                if v.event_id in auth_ids
+            }
+        else:
+            context.auth_events = {}
+
+        context.prev_state_events = prev_state
+        defer.returnValue(context)
+
+    @defer.inlineCallbacks
     @log_function
-    def resolve_state_groups(self, event_ids):
+    def resolve_state_groups(self, event_ids, event_type=None, state_key=""):
         """ Given a list of event_ids this method fetches the state at each
         event, resolves conflicts between them and returns them.
 
@@ -156,7 +174,14 @@ class StateHandler(object):
                 (e.type, e.state_key): e
                 for e in state_list
             }
-            defer.returnValue((name, state))
+            prev_state = state.get((event_type, state_key), None)
+            if prev_state:
+                prev_state = prev_state.event_id
+                prev_states = [prev_state]
+            else:
+                prev_states = []
+
+            defer.returnValue((name, state, prev_states))
 
         state = {}
         for group, g_state in state_groups.items():
@@ -177,6 +202,14 @@ class StateHandler(object):
             if len(v.values()) > 1
         }
 
+        if event_type:
+            prev_states_events = conflicted_state.get(
+                (event_type, state_key), []
+            )
+            prev_states = [s.event_id for s in prev_states_events]
+        else:
+            prev_states = []
+
         try:
             new_state = {}
             new_state.update(unconflicted_state)
@@ -186,11 +219,11 @@ class StateHandler(object):
             logger.exception("Failed to resolve state")
             raise
 
-        defer.returnValue((None, new_state))
+        defer.returnValue((None, new_state, prev_states))
 
     def _get_power_level_from_event_state(self, event, user_id):
         if hasattr(event, "old_state_events") and event.old_state_events:
-            key = (RoomPowerLevelsEvent.TYPE, "", )
+            key = (EventTypes.PowerLevels, "", )
             power_level_event = event.old_state_events.get(key)
             level = None
             if power_level_event:
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index ad1765e04d..ac3bf5cee5 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -15,12 +15,8 @@
 
 from twisted.internet import defer
 
-from synapse.api.events.room import (
-    RoomMemberEvent, RoomTopicEvent, FeedbackEvent, RoomNameEvent,
-    RoomRedactionEvent,
-)
-
 from synapse.util.logutils import log_function
+from synapse.api.constants import EventTypes
 
 from .directory import DirectoryStore
 from .feedback import FeedbackStore
@@ -34,11 +30,13 @@ from .transactions import TransactionStore
 from .keys import KeyStore
 from .event_federation import EventFederationStore
 from .pusher import PusherStore
+from .media_repository import MediaRepositoryStore
 
 from .state import StateStore
 from .signatures import SignatureStore
 
 from syutil.base64util import decode_base64
+from syutil.jsonutil import encode_canonical_json
 
 from synapse.crypto.event_signing import compute_event_reference_hash
 
@@ -63,7 +61,8 @@ SCHEMAS = [
     "state",
     "event_edges",
     "event_signatures",
-    "pusher"
+    "pusher",
+    "media_repository",
 ]
 
 
@@ -83,11 +82,13 @@ class DataStore(RoomMemberStore, RoomStore,
                 RegistrationStore, StreamStore, ProfileStore, FeedbackStore,
                 PresenceStore, TransactionStore,
                 DirectoryStore, KeyStore, StateStore, SignatureStore,
-                EventFederationStore, PusherStore, ):
+                EventFederationStore,
+                MediaRepositoryStore,
+                PusherStore,
+                ):
 
     def __init__(self, hs):
         super(DataStore, self).__init__(hs)
-        self.event_factory = hs.get_event_factory()
         self.hs = hs
 
         self.min_token_deferred = self._get_min_token()
@@ -95,8 +96,8 @@ class DataStore(RoomMemberStore, RoomStore,
 
     @defer.inlineCallbacks
     @log_function
-    def persist_event(self, event, backfilled=False, is_new_state=True,
-                      current_state=None):
+    def persist_event(self, event, context, backfilled=False,
+                      is_new_state=True, current_state=None):
         stream_ordering = None
         if backfilled:
             if not self.min_token_deferred.called:
@@ -109,6 +110,7 @@ class DataStore(RoomMemberStore, RoomStore,
                 "persist_event",
                 self._persist_event_txn,
                 event=event,
+                context=context,
                 backfilled=backfilled,
                 stream_ordering=stream_ordering,
                 is_new_state=is_new_state,
@@ -119,50 +121,66 @@ class DataStore(RoomMemberStore, RoomStore,
 
     @defer.inlineCallbacks
     def get_event(self, event_id, allow_none=False):
-        events_dict = yield self._simple_select_one(
-            "events",
-            {"event_id": event_id},
-            [
-                "event_id",
-                "type",
-                "room_id",
-                "content",
-                "unrecognized_keys",
-                "depth",
-            ],
-            allow_none=allow_none,
-        )
+        events = yield self._get_events([event_id])
 
-        if not events_dict:
-            defer.returnValue(None)
+        if not events:
+            if allow_none:
+                defer.returnValue(None)
+            else:
+                raise RuntimeError("Could not find event %s" % (event_id,))
 
-        event = yield self._parse_events([events_dict])
-        defer.returnValue(event[0])
+        defer.returnValue(events[0])
 
     @log_function
-    def _persist_event_txn(self, txn, event, backfilled, stream_ordering=None,
-                           is_new_state=True, current_state=None):
-        if event.type == RoomMemberEvent.TYPE:
+    def _persist_event_txn(self, txn, event, context, backfilled,
+                           stream_ordering=None, is_new_state=True,
+                           current_state=None):
+        if event.type == EventTypes.Member:
             self._store_room_member_txn(txn, event)
-        elif event.type == FeedbackEvent.TYPE:
+        elif event.type == EventTypes.Feedback:
             self._store_feedback_txn(txn, event)
-        elif event.type == RoomNameEvent.TYPE:
+        elif event.type == EventTypes.Name:
             self._store_room_name_txn(txn, event)
-        elif event.type == RoomTopicEvent.TYPE:
+        elif event.type == EventTypes.Topic:
             self._store_room_topic_txn(txn, event)
-        elif event.type == RoomRedactionEvent.TYPE:
+        elif event.type == EventTypes.Redaction:
             self._store_redaction(txn, event)
 
         outlier = False
-        if hasattr(event, "outlier"):
-            outlier = event.outlier
+        if hasattr(event.internal_metadata, "outlier"):
+            outlier = event.internal_metadata.outlier
+
+        event_dict = {
+            k: v
+            for k, v in event.get_dict().items()
+            if k not in [
+                "redacted",
+                "redacted_because",
+            ]
+        }
+
+        metadata_json = encode_canonical_json(
+            event.internal_metadata.get_dict()
+        )
+
+        self._simple_insert_txn(
+            txn,
+            table="event_json",
+            values={
+                "event_id": event.event_id,
+                "room_id": event.room_id,
+                "internal_metadata": metadata_json.decode("UTF-8"),
+                "json": encode_canonical_json(event_dict).decode("UTF-8"),
+            },
+            or_replace=True,
+        )
 
         vals = {
             "topological_ordering": event.depth,
             "event_id": event.event_id,
             "type": event.type,
             "room_id": event.room_id,
-            "content": json.dumps(event.content),
+            "content": json.dumps(event.get_dict()["content"]),
             "processed": True,
             "outlier": outlier,
             "depth": event.depth,
@@ -173,7 +191,7 @@ class DataStore(RoomMemberStore, RoomStore,
 
         unrec = {
             k: v
-            for k, v in event.get_full_dict().items()
+            for k, v in event.get_dict().items()
             if k not in vals.keys() and k not in [
                 "redacted",
                 "redacted_because",
@@ -208,7 +226,8 @@ class DataStore(RoomMemberStore, RoomStore,
             room_id=event.room_id,
         )
 
-        self._store_state_groups_txn(txn, event)
+        if not outlier:
+            self._store_state_groups_txn(txn, event, context)
 
         if current_state:
             txn.execute(
@@ -302,16 +321,6 @@ class DataStore(RoomMemberStore, RoomStore,
                 txn, event.event_id, hash_alg, hash_bytes,
             )
 
-        if hasattr(event, "signatures"):
-            logger.debug("sigs: %s", event.signatures)
-            for name, sigs in event.signatures.items():
-                for key_id, signature_base64 in sigs.items():
-                    signature_bytes = decode_base64(signature_base64)
-                    self._store_event_signature_txn(
-                        txn, event.event_id, name, key_id,
-                        signature_bytes,
-                    )
-
         for prev_event_id, prev_hashes in event.prev_events:
             for alg, hash_base64 in prev_hashes.items():
                 hash_bytes = decode_base64(hash_base64)
@@ -413,86 +422,6 @@ class DataStore(RoomMemberStore, RoomStore,
             ],
         )
 
-    def snapshot_room(self, event):
-        """Snapshot the room for an update by a user
-        Args:
-            room_id (synapse.types.RoomId): The room to snapshot.
-            user_id (synapse.types.UserId): The user to snapshot the room for.
-            state_type (str): Optional state type to snapshot.
-            state_key (str): Optional state key to snapshot.
-        Returns:
-            synapse.storage.Snapshot: A snapshot of the state of the room.
-        """
-        def _snapshot(txn):
-            prev_events = self._get_latest_events_in_room(
-                txn,
-                event.room_id
-            )
-
-            prev_state = None
-            state_key = None
-            if hasattr(event, "state_key"):
-                state_key = event.state_key
-                prev_state = self._get_latest_state_in_room(
-                    txn,
-                    event.room_id,
-                    type=event.type,
-                    state_key=state_key,
-                )
-
-            return Snapshot(
-                store=self,
-                room_id=event.room_id,
-                user_id=event.user_id,
-                prev_events=prev_events,
-                prev_state=prev_state,
-                state_type=event.type,
-                state_key=state_key,
-            )
-
-        return self.runInteraction("snapshot_room", _snapshot)
-
-
-class Snapshot(object):
-    """Snapshot of the state of a room
-    Args:
-        store (DataStore): The datastore.
-        room_id (RoomId): The room of the snapshot.
-        user_id (UserId): The user this snapshot is for.
-        prev_events (list): The list of event ids this snapshot is after.
-        membership_state (RoomMemberEvent): The current state of the user in
-            the room.
-        state_type (str, optional): State type captured by the snapshot
-        state_key (str, optional): State key captured by the snapshot
-        prev_state_pdu (PduEntry, optional): pdu id of
-            the previous value of the state type and key in the room.
-    """
-
-    def __init__(self, store, room_id, user_id, prev_events,
-                 prev_state, state_type=None, state_key=None):
-        self.store = store
-        self.room_id = room_id
-        self.user_id = user_id
-        self.prev_events = prev_events
-        self.prev_state = prev_state
-        self.state_type = state_type
-        self.state_key = state_key
-
-    def fill_out_prev_events(self, event):
-        if not hasattr(event, "prev_events"):
-            event.prev_events = [
-                (event_id, hashes)
-                for event_id, hashes, _ in self.prev_events
-            ]
-
-            if self.prev_events:
-                event.depth = max([int(v) for _, _, v in self.prev_events]) + 1
-            else:
-                event.depth = 0
-
-        if not hasattr(event, "prev_state") and self.prev_state is not None:
-            event.prev_state = self.prev_state
-
 
 def schema_path(schema):
     """ Get a filesystem path for the named database schema
@@ -520,6 +449,14 @@ def read_schema(schema):
         return schema_file.read()
 
 
+class PrepareDatabaseException(Exception):
+    pass
+
+
+class UpgradeDatabaseException(PrepareDatabaseException):
+    pass
+
+
 def prepare_database(db_conn):
     """ Set up all the dbs. Since all the *.sql have IF NOT EXISTS, so we
     don't have to worry about overwriting existing content.
@@ -544,6 +481,10 @@ def prepare_database(db_conn):
 
             # Run every version since after the current version.
             for v in range(user_version + 1, SCHEMA_VERSION + 1):
+                if v == 10:
+                    raise UpgradeDatabaseException(
+                        "No delta for version 10"
+                    )
                 sql_script = read_schema("delta/v%d" % (v))
                 c.executescript(sql_script)
 
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index eb8cc4a9f3..efb2664680 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -15,15 +15,14 @@
 import logging
 
 from synapse.api.errors import StoreError
-from synapse.api.events.utils import prune_event
+from synapse.events import FrozenEvent
+from synapse.events.utils import prune_event
 from synapse.util.logutils import log_function
 from synapse.util.logcontext import PreserveLoggingContext, LoggingContext
-from syutil.base64util import encode_base64
 
 from twisted.internet import defer
 
 import collections
-import copy
 import json
 import sys
 import time
@@ -84,7 +83,6 @@ class SQLBaseStore(object):
     def __init__(self, hs):
         self.hs = hs
         self._db_pool = hs.get_db_pool()
-        self.event_factory = hs.get_event_factory()
         self._clock = hs.get_clock()
 
     @defer.inlineCallbacks
@@ -481,123 +479,77 @@ class SQLBaseStore(object):
 
         return self.runInteraction("_simple_max_id", func)
 
-    def _parse_event_from_row(self, row_dict):
-        d = copy.deepcopy({k: v for k, v in row_dict.items()})
-
-        d.pop("stream_ordering", None)
-        d.pop("topological_ordering", None)
-        d.pop("processed", None)
-        d["origin_server_ts"] = d.pop("ts", 0)
-        replaces_state = d.pop("prev_state", None)
+    def _get_events(self, event_ids):
+        return self.runInteraction(
+            "_get_events", self._get_events_txn, event_ids
+        )
 
-        if replaces_state:
-            d["replaces_state"] = replaces_state
+    def _get_events_txn(self, txn, event_ids):
+        events = []
+        for e_id in event_ids:
+            ev = self._get_event_txn(txn, e_id)
 
-        d.update(json.loads(row_dict["unrecognized_keys"]))
-        d["content"] = json.loads(d["content"])
-        del d["unrecognized_keys"]
+            if ev:
+                events.append(ev)
 
-        if "age_ts" not in d:
-            # For compatibility
-            d["age_ts"] = d.get("origin_server_ts", 0)
+        return events
 
-        return self.event_factory.create_event(
-            etype=d["type"],
-            **d
+    def _get_event_txn(self, txn, event_id, check_redacted=True,
+                       get_prev_content=True):
+        sql = (
+            "SELECT internal_metadata, json, r.event_id FROM event_json as e "
+            "LEFT JOIN redactions as r ON e.event_id = r.redacts "
+            "WHERE e.event_id = ? "
+            "LIMIT 1 "
         )
 
-    def _get_events_txn(self, txn, event_ids):
-        # FIXME (erikj): This should be batched?
+        txn.execute(sql, (event_id,))
 
-        sql = "SELECT * FROM events WHERE event_id = ? ORDER BY rowid asc"
+        res = txn.fetchone()
 
-        event_rows = []
-        for e_id in event_ids:
-            c = txn.execute(sql, (e_id,))
-            event_rows.extend(self.cursor_to_dict(c))
+        if not res:
+            return None
 
-        return self._parse_events_txn(txn, event_rows)
+        internal_metadata, js, redacted = res
 
-    def _parse_events(self, rows):
-        return self.runInteraction(
-            "_parse_events", self._parse_events_txn, rows
-        )
+        d = json.loads(js)
+        internal_metadata = json.loads(internal_metadata)
 
-    def _parse_events_txn(self, txn, rows):
-        events = [self._parse_event_from_row(r) for r in rows]
+        ev = FrozenEvent(d, internal_metadata_dict=internal_metadata)
 
-        select_event_sql = (
-            "SELECT * FROM events WHERE event_id = ? ORDER BY rowid asc"
-        )
+        if check_redacted and redacted:
+            ev = prune_event(ev)
 
-        for i, ev in enumerate(events):
-            signatures = self._get_event_signatures_txn(
-                txn, ev.event_id,
+            ev.unsigned["redacted_by"] = redacted
+            # Get the redaction event.
+
+            because = self._get_event_txn(
+                txn,
+                redacted,
+                check_redacted=False
             )
 
-            ev.signatures = {
-                n: {
-                    k: encode_base64(v) for k, v in s.items()
-                }
-                for n, s in signatures.items()
-            }
+            if because:
+                ev.unsigned["redacted_because"] = because
 
-            hashes = self._get_event_content_hashes_txn(
-                txn, ev.event_id,
-            )
+        if get_prev_content and "replaces_state" in ev.unsigned:
+            ev.unsigned["prev_content"] = self._get_event_txn(
+                txn,
+                ev.unsigned["replaces_state"],
+                get_prev_content=False,
+            ).get_dict()["content"]
 
-            ev.hashes = {
-                k: encode_base64(v) for k, v in hashes.items()
-            }
-
-            prevs = self._get_prev_events_and_state(txn, ev.event_id)
-
-            ev.prev_events = [
-                (e_id, h)
-                for e_id, h, is_state in prevs
-                if is_state == 0
-            ]
-
-            ev.auth_events = self._get_auth_events(txn, ev.event_id)
-
-            if hasattr(ev, "state_key"):
-                ev.prev_state = [
-                    (e_id, h)
-                    for e_id, h, is_state in prevs
-                    if is_state == 1
-                ]
-
-                if hasattr(ev, "replaces_state"):
-                    # Load previous state_content.
-                    # FIXME (erikj): Handle multiple prev_states.
-                    cursor = txn.execute(
-                        select_event_sql,
-                        (ev.replaces_state,)
-                    )
-                    prevs = self.cursor_to_dict(cursor)
-                    if prevs:
-                        prev = self._parse_event_from_row(prevs[0])
-                        ev.prev_content = prev.content
-
-            if not hasattr(ev, "redacted"):
-                logger.debug("Doesn't have redacted key: %s", ev)
-                ev.redacted = self._has_been_redacted_txn(txn, ev)
-
-            if ev.redacted:
-                # Get the redaction event.
-                select_event_sql = "SELECT * FROM events WHERE event_id = ?"
-                txn.execute(select_event_sql, (ev.redacted,))
-
-                del_evs = self._parse_events_txn(
-                    txn, self.cursor_to_dict(txn)
-                )
+        return ev
 
-                if del_evs:
-                    ev = prune_event(ev)
-                    events[i] = ev
-                    ev.redacted_because = del_evs[0]
+    def _parse_events(self, rows):
+        return self.runInteraction(
+            "_parse_events", self._parse_events_txn, rows
+        )
 
-        return events
+    def _parse_events_txn(self, txn, rows):
+        event_ids = [r["event_id"] for r in rows]
+
+        return self._get_events_txn(txn, event_ids)
 
     def _has_been_redacted_txn(self, txn, event):
         sql = "SELECT event_id FROM redactions WHERE redacts = ?"
@@ -695,7 +647,7 @@ class JoinHelper(object):
     to dump the results into.
 
     Attributes:
-        taples (list): List of `Table` classes
+        tables (list): List of `Table` classes
         EntryType (type)
     """
 
diff --git a/synapse/storage/event_federation.py b/synapse/storage/event_federation.py
index 6c559f8f63..ced066f407 100644
--- a/synapse/storage/event_federation.py
+++ b/synapse/storage/event_federation.py
@@ -177,14 +177,15 @@ class EventFederationStore(SQLBaseStore):
             retcols=["prev_event_id", "is_state"],
         )
 
+        hashes = self._get_prev_event_hashes_txn(txn, event_id)
+
         results = []
         for d in res:
-            hashes = self._get_event_reference_hashes_txn(
-                txn,
-                d["prev_event_id"]
-            )
+            edge_hash = self._get_event_reference_hashes_txn(txn, d["prev_event_id"])
+            edge_hash.update(hashes.get(d["prev_event_id"], {}))
             prev_hashes = {
-                k: encode_base64(v) for k, v in hashes.items()
+                k: encode_base64(v)
+                for k, v in edge_hash.items()
                 if k == "sha256"
             }
             results.append((d["prev_event_id"], prev_hashes, d["is_state"]))
diff --git a/synapse/storage/media_repository.py b/synapse/storage/media_repository.py
new file mode 100644
index 0000000000..18c068d3d9
--- /dev/null
+++ b/synapse/storage/media_repository.py
@@ -0,0 +1,129 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from _base import SQLBaseStore
+
+
+class MediaRepositoryStore(SQLBaseStore):
+    """Persistence for attachments and avatars"""
+
+    def get_default_thumbnails(self, top_level_type, sub_type):
+        return []
+
+    def get_local_media(self, media_id):
+        """Get the metadata for a local piece of media
+        Returns:
+            None if the meia_id doesn't exist.
+        """
+        return self._simple_select_one(
+            "local_media_repository",
+            {"media_id": media_id},
+            ("media_type", "media_length", "upload_name", "created_ts"),
+            allow_none=True,
+        )
+
+    def store_local_media(self, media_id, media_type, time_now_ms, upload_name,
+                          media_length, user_id):
+        return self._simple_insert(
+            "local_media_repository",
+            {
+                "media_id": media_id,
+                "media_type": media_type,
+                "created_ts": time_now_ms,
+                "upload_name": upload_name,
+                "media_length": media_length,
+                "user_id": user_id.to_string(),
+            }
+        )
+
+    def get_local_media_thumbnails(self, media_id):
+        return self._simple_select_list(
+            "local_media_repository_thumbnails",
+            {"media_id": media_id},
+            (
+                "thumbnail_width", "thumbnail_height", "thumbnail_method",
+                "thumbnail_type", "thumbnail_length",
+            )
+        )
+
+    def store_local_thumbnail(self, media_id, thumbnail_width,
+                              thumbnail_height, thumbnail_type,
+                              thumbnail_method, thumbnail_length):
+        return self._simple_insert(
+            "local_media_repository_thumbnails",
+            {
+                "media_id": media_id,
+                "thumbnail_width": thumbnail_width,
+                "thumbnail_height": thumbnail_height,
+                "thumbnail_method": thumbnail_method,
+                "thumbnail_type": thumbnail_type,
+                "thumbnail_length": thumbnail_length,
+            }
+        )
+
+    def get_cached_remote_media(self, origin, media_id):
+        return self._simple_select_one(
+            "remote_media_cache",
+            {"media_origin": origin, "media_id": media_id},
+            (
+                "media_type", "media_length", "upload_name", "created_ts",
+                "filesystem_id",
+            ),
+            allow_none=True,
+        )
+
+    def store_cached_remote_media(self, origin, media_id, media_type,
+                                  media_length, time_now_ms, upload_name,
+                                  filesystem_id):
+        return self._simple_insert(
+            "remote_media_cache",
+            {
+                "media_origin": origin,
+                "media_id": media_id,
+                "media_type": media_type,
+                "media_length": media_length,
+                "created_ts": time_now_ms,
+                "upload_name": upload_name,
+                "filesystem_id": filesystem_id,
+            }
+        )
+
+    def get_remote_media_thumbnails(self, origin, media_id):
+        return self._simple_select_list(
+            "remote_media_cache_thumbnails",
+            {"media_origin": origin, "media_id": media_id},
+            (
+                "thumbnail_width", "thumbnail_height", "thumbnail_method",
+                "thumbnail_type", "thumbnail_length", "filesystem_id",
+            )
+        )
+
+    def store_remote_media_thumbnail(self, origin, media_id, filesystem_id,
+                                     thumbnail_width, thumbnail_height,
+                                     thumbnail_type, thumbnail_method,
+                                     thumbnail_length):
+        return self._simple_insert(
+            "remote_media_cache_thumbnails",
+            {
+                "media_origin": origin,
+                "media_id": media_id,
+                "thumbnail_width": thumbnail_width,
+                "thumbnail_height": thumbnail_height,
+                "thumbnail_method": thumbnail_method,
+                "thumbnail_type": thumbnail_type,
+                "thumbnail_length": thumbnail_length,
+                "filesystem_id": filesystem_id,
+            }
+        )
diff --git a/synapse/storage/schema/delta/v9.sql b/synapse/storage/schema/delta/v9.sql
new file mode 100644
index 0000000000..0af29733a0
--- /dev/null
+++ b/synapse/storage/schema/delta/v9.sql
@@ -0,0 +1,79 @@
+/* Copyright 2014 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+-- To track destination health
+CREATE TABLE IF NOT EXISTS destinations(
+    destination TEXT PRIMARY KEY,
+    retry_last_ts INTEGER,
+    retry_interval INTEGER
+);
+
+
+CREATE TABLE IF NOT EXISTS local_media_repository (
+    media_id TEXT, -- The id used to refer to the media.
+    media_type TEXT, -- The MIME-type of the media.
+    media_length INTEGER, -- Length of the media in bytes.
+    created_ts INTEGER, -- When the content was uploaded in ms.
+    upload_name TEXT, -- The name the media was uploaded with.
+    user_id TEXT, -- The user who uploaded the file.
+    CONSTRAINT uniqueness UNIQUE (media_id)
+);
+
+CREATE TABLE IF NOT EXISTS local_media_repository_thumbnails (
+    media_id TEXT, -- The id used to refer to the media.
+    thumbnail_width INTEGER, -- The width of the thumbnail in pixels.
+    thumbnail_height INTEGER, -- The height of the thumbnail in pixels.
+    thumbnail_type TEXT, -- The MIME-type of the thumbnail.
+    thumbnail_method TEXT, -- The method used to make the thumbnail.
+    thumbnail_length INTEGER, -- The length of the thumbnail in bytes.
+    CONSTRAINT uniqueness UNIQUE (
+        media_id, thumbnail_width, thumbnail_height, thumbnail_type
+    )
+);
+
+CREATE INDEX IF NOT EXISTS local_media_repository_thumbnails_media_id
+    ON local_media_repository_thumbnails (media_id);
+
+CREATE TABLE IF NOT EXISTS remote_media_cache (
+    media_origin TEXT, -- The remote HS the media came from.
+    media_id TEXT, -- The id used to refer to the media on that server.
+    media_type TEXT, -- The MIME-type of the media.
+    created_ts INTEGER, -- When the content was uploaded in ms.
+    upload_name TEXT, -- The name the media was uploaded with.
+    media_length INTEGER, -- Length of the media in bytes.
+    filesystem_id TEXT, -- The name used to store the media on disk.
+    CONSTRAINT uniqueness UNIQUE (media_origin, media_id)
+);
+
+CREATE TABLE IF NOT EXISTS remote_media_cache_thumbnails (
+    media_origin TEXT, -- The remote HS the media came from.
+    media_id TEXT, -- The id used to refer to the media.
+    thumbnail_width INTEGER, -- The width of the thumbnail in pixels.
+    thumbnail_height INTEGER, -- The height of the thumbnail in pixels.
+    thumbnail_method TEXT, -- The method used to make the thumbnail
+    thumbnail_type TEXT, -- The MIME-type of the thumbnail.
+    thumbnail_length INTEGER, -- The length of the thumbnail in bytes.
+    filesystem_id TEXT, -- The name used to store the media on disk.
+    CONSTRAINT uniqueness UNIQUE (
+        media_origin, media_id, thumbnail_width, thumbnail_height,
+        thumbnail_type, thumbnail_type
+    )
+);
+
+CREATE INDEX IF NOT EXISTS remote_media_cache_thumbnails_media_id
+    ON local_media_repository_thumbnails (media_id);
+
+
+PRAGMA user_version = 9;
diff --git a/synapse/storage/schema/im.sql b/synapse/storage/schema/im.sql
index 8ba732a23b..253f9f779b 100644
--- a/synapse/storage/schema/im.sql
+++ b/synapse/storage/schema/im.sql
@@ -32,6 +32,19 @@ CREATE INDEX IF NOT EXISTS events_stream_ordering ON events (stream_ordering);
 CREATE INDEX IF NOT EXISTS events_topological_ordering ON events (topological_ordering);
 CREATE INDEX IF NOT EXISTS events_room_id ON events (room_id);
 
+
+CREATE TABLE IF NOT EXISTS event_json(
+    event_id TEXT NOT NULL,
+    room_id TEXT NOT NULL,
+    internal_metadata NOT NULL,
+    json BLOB NOT NULL,
+    CONSTRAINT ev_j_uniq UNIQUE (event_id)
+);
+
+CREATE INDEX IF NOT EXISTS event_json_id ON event_json(event_id);
+CREATE INDEX IF NOT EXISTS event_json_room_id ON event_json(room_id);
+
+
 CREATE TABLE IF NOT EXISTS state_events(
     event_id TEXT NOT NULL,
     room_id TEXT NOT NULL,
diff --git a/synapse/storage/schema/media_repository.sql b/synapse/storage/schema/media_repository.sql
new file mode 100644
index 0000000000..b785fa0208
--- /dev/null
+++ b/synapse/storage/schema/media_repository.sql
@@ -0,0 +1,68 @@
+/* Copyright 2014 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+CREATE TABLE IF NOT EXISTS local_media_repository (
+    media_id TEXT, -- The id used to refer to the media.
+    media_type TEXT, -- The MIME-type of the media.
+    media_length INTEGER, -- Length of the media in bytes.
+    created_ts INTEGER, -- When the content was uploaded in ms.
+    upload_name TEXT, -- The name the media was uploaded with.
+    user_id TEXT, -- The user who uploaded the file.
+    CONSTRAINT uniqueness UNIQUE (media_id)
+);
+
+CREATE TABLE IF NOT EXISTS local_media_repository_thumbnails (
+    media_id TEXT, -- The id used to refer to the media.
+    thumbnail_width INTEGER, -- The width of the thumbnail in pixels.
+    thumbnail_height INTEGER, -- The height of the thumbnail in pixels.
+    thumbnail_type TEXT, -- The MIME-type of the thumbnail.
+    thumbnail_method TEXT, -- The method used to make the thumbnail.
+    thumbnail_length INTEGER, -- The length of the thumbnail in bytes.
+    CONSTRAINT uniqueness UNIQUE (
+        media_id, thumbnail_width, thumbnail_height, thumbnail_type
+    )
+);
+
+CREATE INDEX IF NOT EXISTS local_media_repository_thumbnails_media_id
+    ON local_media_repository_thumbnails (media_id);
+
+CREATE TABLE IF NOT EXISTS remote_media_cache (
+    media_origin TEXT, -- The remote HS the media came from.
+    media_id TEXT, -- The id used to refer to the media on that server.
+    media_type TEXT, -- The MIME-type of the media.
+    created_ts INTEGER, -- When the content was uploaded in ms.
+    upload_name TEXT, -- The name the media was uploaded with.
+    media_length INTEGER, -- Length of the media in bytes.
+    filesystem_id TEXT, -- The name used to store the media on disk.
+    CONSTRAINT uniqueness UNIQUE (media_origin, media_id)
+);
+
+CREATE TABLE IF NOT EXISTS remote_media_cache_thumbnails (
+    media_origin TEXT, -- The remote HS the media came from.
+    media_id TEXT, -- The id used to refer to the media.
+    thumbnail_width INTEGER, -- The width of the thumbnail in pixels.
+    thumbnail_height INTEGER, -- The height of the thumbnail in pixels.
+    thumbnail_method TEXT, -- The method used to make the thumbnail
+    thumbnail_type TEXT, -- The MIME-type of the thumbnail.
+    thumbnail_length INTEGER, -- The length of the thumbnail in bytes.
+    filesystem_id TEXT, -- The name used to store the media on disk.
+    CONSTRAINT uniqueness UNIQUE (
+        media_origin, media_id, thumbnail_width, thumbnail_height,
+        thumbnail_type, thumbnail_type
+    )
+);
+
+CREATE INDEX IF NOT EXISTS remote_media_cache_thumbnails_media_id
+    ON local_media_repository_thumbnails (media_id);
diff --git a/synapse/storage/schema/state.sql b/synapse/storage/schema/state.sql
index 44f7aafb27..2c48d6daca 100644
--- a/synapse/storage/schema/state.sql
+++ b/synapse/storage/schema/state.sql
@@ -29,7 +29,8 @@ CREATE TABLE IF NOT EXISTS state_groups_state(
 
 CREATE TABLE IF NOT EXISTS event_to_state_groups(
     event_id TEXT NOT NULL,
-    state_group INTEGER NOT NULL
+    state_group INTEGER NOT NULL,
+    CONSTRAINT event_to_state_groups_uniq UNIQUE (event_id)
 );
 
 CREATE INDEX IF NOT EXISTS state_groups_id ON state_groups(id);
diff --git a/synapse/storage/schema/transactions.sql b/synapse/storage/schema/transactions.sql
index 88e3e4e04d..de461bfa15 100644
--- a/synapse/storage/schema/transactions.sql
+++ b/synapse/storage/schema/transactions.sql
@@ -59,3 +59,9 @@ CREATE INDEX IF NOT EXISTS transaction_id_to_pdu_tx ON transaction_id_to_pdu(tra
 CREATE INDEX IF NOT EXISTS transaction_id_to_pdu_dest ON transaction_id_to_pdu(destination);
 CREATE INDEX IF NOT EXISTS transaction_id_to_pdu_index ON transaction_id_to_pdu(transaction_id, destination);
 
+-- To track destination health
+CREATE TABLE IF NOT EXISTS destinations(
+    destination TEXT PRIMARY KEY,
+    retry_last_ts INTEGER,
+    retry_interval INTEGER
+);
diff --git a/synapse/storage/signatures.py b/synapse/storage/signatures.py
index eea4f21065..3a705119fd 100644
--- a/synapse/storage/signatures.py
+++ b/synapse/storage/signatures.py
@@ -13,8 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from twisted.internet import defer
+
 from _base import SQLBaseStore
 
+from syutil.base64util import encode_base64
+
 
 class SignatureStore(SQLBaseStore):
     """Persistence for event signatures and hashes"""
@@ -67,6 +71,21 @@ class SignatureStore(SQLBaseStore):
             f
         )
 
+    @defer.inlineCallbacks
+    def add_event_hashes(self, event_ids):
+        hashes = yield self.get_event_reference_hashes(
+            event_ids
+        )
+        hashes = [
+            {
+                k: encode_base64(v) for k, v in h.items()
+                if k == "sha256"
+            }
+            for h in hashes
+        ]
+
+        defer.returnValue(zip(event_ids, hashes))
+
     def _get_event_reference_hashes_txn(self, txn, event_id):
         """Get all the hashes for a given PDU.
         Args:
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index e0f44b3e59..afe3e5edea 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -86,11 +86,16 @@ class StateStore(SQLBaseStore):
             self._store_state_groups_txn, event
         )
 
-    def _store_state_groups_txn(self, txn, event):
-        if event.state_events is None:
+    def _store_state_groups_txn(self, txn, event, context):
+        if context.current_state is None:
             return
 
-        state_group = event.state_group
+        state_events = context.current_state
+
+        if event.is_state():
+            state_events[(event.type, event.state_key)] = event
+
+        state_group = context.state_group
         if not state_group:
             state_group = self._simple_insert_txn(
                 txn,
@@ -102,7 +107,7 @@ class StateStore(SQLBaseStore):
                 or_ignore=True,
             )
 
-            for state in event.state_events.values():
+            for state in state_events.values():
                 self._simple_insert_txn(
                     txn,
                     table="state_groups_state",
diff --git a/synapse/storage/transactions.py b/synapse/storage/transactions.py
index 00d0f48082..423cc3f02a 100644
--- a/synapse/storage/transactions.py
+++ b/synapse/storage/transactions.py
@@ -17,6 +17,8 @@ from ._base import SQLBaseStore, Table
 
 from collections import namedtuple
 
+from twisted.internet import defer
+
 import logging
 
 logger = logging.getLogger(__name__)
@@ -26,6 +28,10 @@ class TransactionStore(SQLBaseStore):
     """A collection of queries for handling PDUs.
     """
 
+    # a write-through cache of DestinationsTable.EntryType indexed by
+    # destination string
+    destination_retry_cache = {}
+
     def get_received_txn_response(self, transaction_id, origin):
         """For an incoming transaction from a given origin, check if we have
         already responded to it. If so, return the response code and response
@@ -114,7 +120,7 @@ class TransactionStore(SQLBaseStore):
     def _prep_send_transaction(self, txn, transaction_id, destination,
                                origin_server_ts):
 
-        # First we find out what the prev_txs should be.
+        # First we find out what the prev_txns should be.
         # Since we know that we are only sending one transaction at a time,
         # we can simply take the last one.
         query = "%s ORDER BY id DESC LIMIT 1" % (
@@ -205,6 +211,92 @@ class TransactionStore(SQLBaseStore):
 
         return ReceivedTransactionsTable.decode_results(txn.fetchall())
 
+    def get_destination_retry_timings(self, destination):
+        """Gets the current retry timings (if any) for a given destination.
+
+        Args:
+            destination (str)
+
+        Returns:
+            None if not retrying
+            Otherwise a DestinationsTable.EntryType for the retry scheme
+        """
+        if destination in self.destination_retry_cache:
+            return defer.succeed(self.destination_retry_cache[destination])
+
+        return self.runInteraction(
+            "get_destination_retry_timings",
+            self._get_destination_retry_timings, destination)
+
+    def _get_destination_retry_timings(cls, txn, destination):
+        query = DestinationsTable.select_statement("destination = ?")
+        txn.execute(query, (destination,))
+        result = txn.fetchall()
+        if result:
+            result = DestinationsTable.decode_single_result(result)
+            if result.retry_last_ts > 0:
+                return result
+            else:
+                return None
+
+    def set_destination_retry_timings(self, destination,
+                                      retry_last_ts, retry_interval):
+        """Sets the current retry timings for a given destination.
+        Both timings should be zero if retrying is no longer occuring.
+
+        Args:
+            destination (str)
+            retry_last_ts (int) - time of last retry attempt in unix epoch ms
+            retry_interval (int) - how long until next retry in ms
+        """
+
+        self.destination_retry_cache[destination] = (
+            DestinationsTable.EntryType(
+                destination,
+                retry_last_ts,
+                retry_interval
+            )
+        )
+
+        # XXX: we could chose to not bother persisting this if our cache thinks
+        # this is a NOOP
+        return self.runInteraction(
+            "set_destination_retry_timings",
+            self._set_destination_retry_timings,
+            destination,
+            retry_last_ts,
+            retry_interval,
+        )
+
+    def _set_destination_retry_timings(cls, txn, destination,
+                                       retry_last_ts, retry_interval):
+
+        query = (
+            "INSERT OR REPLACE INTO %s "
+            "(destination, retry_last_ts, retry_interval) "
+            "VALUES (?, ?, ?) "
+        ) % DestinationsTable.table_name
+
+        txn.execute(query, (destination, retry_last_ts, retry_interval))
+
+    def get_destinations_needing_retry(self):
+        """Get all destinations which are due a retry for sending a transaction.
+
+        Returns:
+            list: A list of `DestinationsTable.EntryType`
+        """
+
+        return self.runInteraction(
+            "get_destinations_needing_retry",
+            self._get_destinations_needing_retry
+        )
+
+    def _get_destinations_needing_retry(cls, txn):
+        where = "retry_last_ts > 0 and retry_next_ts < now()"
+        query = DestinationsTable.select_statement(where)
+        txn.execute(query)
+        return DestinationsTable.decode_results(txn.fetchall())
+
 
 class ReceivedTransactionsTable(Table):
     table_name = "received_transactions"
@@ -247,3 +339,15 @@ class TransactionsToPduTable(Table):
     ]
 
     EntryType = namedtuple("TransactionsToPduEntry", fields)
+
+
+class DestinationsTable(Table):
+    table_name = "destinations"
+
+    fields = [
+        "destination",
+        "retry_last_ts",
+        "retry_interval",
+    ]
+
+    EntryType = namedtuple("DestinationsEntry", fields)
diff --git a/synapse/types.py b/synapse/types.py
index 649ff2f7d7..7c533193e1 100644
--- a/synapse/types.py
+++ b/synapse/types.py
@@ -19,7 +19,7 @@ from collections import namedtuple
 
 
 class DomainSpecificString(
-        namedtuple("DomainSpecificString", ("localpart", "domain", "is_mine"))
+        namedtuple("DomainSpecificString", ("localpart", "domain"))
 ):
     """Common base class among ID/name strings that have a local part and a
     domain name, prefixed with a sigil.
@@ -28,15 +28,13 @@ class DomainSpecificString(
 
         'localpart' : The local part of the name (without the leading sigil)
         'domain' : The domain part of the name
-        'is_mine' : Boolean indicating if the domain name is recognised by the
-            HomeServer as being its own
     """
 
     # Deny iteration because it will bite you if you try to create a singleton
     # set by:
     #    users = set(user)
     def __iter__(self):
-        raise ValueError("Attempted to iterate a %s" % (type(self).__name__))
+        raise ValueError("Attempted to iterate a %s" % (type(self).__name__,))
 
     # Because this class is a namedtuple of strings and booleans, it is deeply
     # immutable.
@@ -47,7 +45,7 @@ class DomainSpecificString(
         return self
 
     @classmethod
-    def from_string(cls, s, hs):
+    def from_string(cls, s):
         """Parse the string given by 's' into a structure object."""
         if s[0] != cls.SIGIL:
             raise SynapseError(400, "Expected %s string to start with '%s'" % (
@@ -66,22 +64,15 @@ class DomainSpecificString(
 
         # This code will need changing if we want to support multiple domain
         # names on one HS
-        is_mine = domain == hs.hostname
-        return cls(localpart=parts[0], domain=domain, is_mine=is_mine)
+        return cls(localpart=parts[0], domain=domain)
 
     def to_string(self):
         """Return a string encoding the fields of the structure object."""
         return "%s%s:%s" % (self.SIGIL, self.localpart, self.domain)
 
     @classmethod
-    def create_local(cls, localpart, hs):
-        """Create a structure on the local domain"""
-        return cls(localpart=localpart, domain=hs.hostname, is_mine=True)
-
-    @classmethod
-    def create(cls, localpart, domain, hs):
-        is_mine = domain == hs.hostname
-        return cls(localpart=localpart, domain=domain, is_mine=is_mine)
+    def create(cls, localpart, domain,):
+        return cls(localpart=localpart, domain=domain)
 
 
 class UserID(DomainSpecificString):
diff --git a/synapse/util/frozenutils.py b/synapse/util/frozenutils.py
new file mode 100644
index 0000000000..fcfb38b3b4
--- /dev/null
+++ b/synapse/util/frozenutils.py
@@ -0,0 +1,46 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from frozendict import frozendict
+
+
+def freeze(o):
+    if isinstance(o, dict) or isinstance(o, frozendict):
+        return frozendict({k: freeze(v) for k, v in o.items()})
+
+    if isinstance(o, basestring):
+        return o
+
+    try:
+        return tuple([freeze(i) for i in o])
+    except TypeError:
+        pass
+
+    return o
+
+
+def unfreeze(o):
+    if isinstance(o, frozendict) or isinstance(o, dict):
+        return dict({k: unfreeze(v) for k, v in o.items()})
+
+    if isinstance(o, basestring):
+        return o
+
+    try:
+        return [unfreeze(i) for i in o]
+    except TypeError:
+        pass
+
+    return o