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-rw-r--r--graph/graph2.py138
-rwxr-xr-xsetup.py1
-rw-r--r--synapse/api/auth.py56
-rw-r--r--synapse/api/constants.py9
-rw-r--r--synapse/api/events/factory.py2
-rw-r--r--synapse/crypto/event_signing.py44
-rw-r--r--synapse/events/__init__.py178
-rw-r--r--synapse/events/builder.py77
-rw-r--r--synapse/events/snapshot.py64
-rw-r--r--synapse/events/utils.py129
-rw-r--r--synapse/events/validator.py71
-rw-r--r--synapse/federation/replication.py43
-rw-r--r--synapse/handlers/_base.py108
-rw-r--r--synapse/handlers/directory.py28
-rw-r--r--synapse/handlers/federation.py248
-rw-r--r--synapse/handlers/message.py45
-rw-r--r--synapse/handlers/presence.py38
-rw-r--r--synapse/handlers/profile.py35
-rw-r--r--synapse/handlers/register.py6
-rw-r--r--synapse/handlers/room.py189
-rw-r--r--synapse/handlers/typing.py4
-rw-r--r--synapse/rest/admin.py2
-rw-r--r--synapse/rest/base.py2
-rw-r--r--synapse/rest/login.py4
-rw-r--r--synapse/rest/presence.py4
-rw-r--r--synapse/rest/register.py4
-rw-r--r--synapse/rest/room.py108
-rw-r--r--synapse/server.py21
-rw-r--r--synapse/state.py89
-rw-r--r--synapse/storage/__init__.py77
-rw-r--r--synapse/storage/_base.py153
-rw-r--r--synapse/storage/schema/im.sql12
-rw-r--r--synapse/storage/schema/state.sql3
-rw-r--r--synapse/storage/signatures.py19
-rw-r--r--synapse/storage/state.py13
-rw-r--r--synapse/types.py21
-rw-r--r--synapse/util/frozenutils.py56
-rw-r--r--tests/federation/test_federation.py18
-rw-r--r--tests/handlers/test_federation.py42
-rw-r--r--tests/handlers/test_room.py68
-rw-r--r--tests/handlers/test_typing.py2
-rw-r--r--tests/storage/test_redaction.py124
-rw-r--r--tests/storage/test_roommember.py49
-rw-r--r--tests/storage/test_stream.py78
-rw-r--r--tests/test_types.py18
45 files changed, 1672 insertions, 828 deletions
diff --git a/graph/graph2.py b/graph/graph2.py
new file mode 100644
index 0000000000..b9b8a562a0
--- /dev/null
+++ b/graph/graph2.py
@@ -0,0 +1,138 @@
+# 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 sqlite3
+import pydot
+import cgi
+import json
+import datetime
+import argparse
+
+from synapse.events import FrozenEvent
+
+
+def make_graph(db_name, room_id, file_prefix):
+    conn = sqlite3.connect(db_name)
+
+    c = conn.execute(
+        "SELECT json FROM event_json where room_id = ?",
+        (room_id,)
+    )
+
+    events = [FrozenEvent(json.loads(e[0])) for e in c.fetchall()]
+
+    events.sort(key=lambda e: e.depth)
+
+    node_map = {}
+    state_groups = {}
+
+    graph = pydot.Dot(graph_name="Test")
+
+    for event in events:
+        c = conn.execute(
+            "SELECT state_group FROM event_to_state_groups "
+            "WHERE event_id = ?",
+            (event.event_id,)
+        )
+
+        res = c.fetchone()
+        state_group = res[0] if res else None
+
+        if state_group is not None:
+            state_groups.setdefault(state_group, []).append(event.event_id)
+
+        t = datetime.datetime.fromtimestamp(
+            float(event.origin_server_ts) / 1000
+        ).strftime('%Y-%m-%d %H:%M:%S,%f')
+
+        content = json.dumps(event.get_dict()["content"])
+
+        label = (
+            "<"
+            "<b>%(name)s </b><br/>"
+            "Type: <b>%(type)s </b><br/>"
+            "State key: <b>%(state_key)s </b><br/>"
+            "Content: <b>%(content)s </b><br/>"
+            "Time: <b>%(time)s </b><br/>"
+            "Depth: <b>%(depth)s </b><br/>"
+            "State group: %(state_group)s<br/>"
+            ">"
+        ) % {
+            "name": event.event_id,
+            "type": event.type,
+            "state_key": event.get("state_key", None),
+            "content": cgi.escape(content, quote=True),
+            "time": t,
+            "depth": event.depth,
+            "state_group": state_group,
+        }
+
+        node = pydot.Node(
+            name=event.event_id,
+            label=label,
+        )
+
+        node_map[event.event_id] = node
+        graph.add_node(node)
+
+    for event in events:
+        for prev_id, _ in event.prev_events:
+            try:
+                end_node = node_map[prev_id]
+            except:
+                end_node = pydot.Node(
+                    name=prev_id,
+                    label="<<b>%s</b>>" % (prev_id,),
+                )
+
+                node_map[prev_id] = end_node
+                graph.add_node(end_node)
+
+            edge = pydot.Edge(node_map[event.event_id], end_node)
+            graph.add_edge(edge)
+
+    for group, event_ids in state_groups.items():
+        if len(event_ids) <= 1:
+            continue
+
+        cluster = pydot.Cluster(
+            str(group),
+            label="<State Group: %s>" % (str(group),)
+        )
+
+        for event_id in event_ids:
+            cluster.add_node(node_map[event_id])
+
+        graph.add_subgraph(cluster)
+
+    graph.write('%s.dot' % file_prefix, format='raw', prog='dot')
+    graph.write_svg("%s.svg" % file_prefix, prog='dot')
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="Generate a PDU graph for a given room by talking "
+                    "to the given homeserver to get the list of PDUs. \n"
+                    "Requires pydot."
+    )
+    parser.add_argument(
+        "-p", "--prefix", dest="prefix",
+        help="String to prefix output files with"
+    )
+    parser.add_argument('db')
+    parser.add_argument('room')
+
+    args = parser.parse_args()
+
+    make_graph(args.db, args.room, args.prefix)
diff --git a/setup.py b/setup.py
index 34012bc7c1..eb410aa6d3 100755
--- a/setup.py
+++ b/setup.py
@@ -41,6 +41,7 @@ setup(
         "pynacl",
         "daemonize",
         "py-bcrypt",
+        "frozendict>=0.4",
         "pillow",
     ],
     dependency_links=[
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 2b0475543d..cd0deeb0e6 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -24,7 +24,7 @@ from synapse.api.events.room import (
     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
 
@@ -351,29 +351,31 @@ 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 == RoomCreateEvent.TYPE:
+            builder.auth_events = []
             return
 
-        auth_events = []
+        auth_ids = []
 
         key = (RoomPowerLevelsEvent.TYPE, "", )
-        power_level_event = event.old_state_events.get(key)
+        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)
+        join_rule_event = context.current_state.get(key)
 
-        key = (RoomMemberEvent.TYPE, event.user_id, )
-        member_event = event.old_state_events.get(key)
+        key = (RoomMemberEvent.TYPE, builder.user_id, )
+        member_event = context.current_state.get(key)
 
         key = (RoomCreateEvent.TYPE, "", )
-        create_event = event.old_state_events.get(key)
+        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")
@@ -381,29 +383,29 @@ class Auth(object):
         else:
             is_public = False
 
-        if event.type == RoomMemberEvent.TYPE:
-            e_type = event.content["membership"]
+        if builder.type == RoomMemberEvent.TYPE:
+            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 member_event and not is_public:
-                    auth_events.append(member_event.event_id)
+                    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):
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 3cafff0e32..7e8c892b64 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -59,3 +59,12 @@ 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"
diff --git a/synapse/api/events/factory.py b/synapse/api/events/factory.py
index a1ec708a81..1b84e2b445 100644
--- a/synapse/api/events/factory.py
+++ b/synapse/api/events/factory.py
@@ -58,7 +58,7 @@ class EventFactory(object):
 
         local_part = str(int(self.clock.time())) + i + random_string(5)
 
-        e_id = EventID.create_local(local_part, self.hs)
+        e_id = EventID.create(local_part, self.hs.hostname)
 
         return e_id.to_string()
 
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..98d7f0e324
--- /dev/null
+++ b/synapse/events/__init__.py
@@ -0,0 +1,178 @@
+# -*- 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
+
+import copy
+
+
+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
+
+
+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):
+        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
+        )
+
+    @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),
+        )
\ No newline at end of file
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/synapse/events/snapshot.py b/synapse/events/snapshot.py
new file mode 100644
index 0000000000..e0cbacc19c
--- /dev/null
+++ b/synapse/events/snapshot.py
@@ -0,0 +1,64 @@
+# -*- 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 twisted.internet import defer
+
+
+class EventSnapshot(object):
+    def __init__(self, prev_events, depth, current_state,
+                 current_state_group):
+        self._prev_events = prev_events
+        self._depth = depth
+        self._current_state = current_state
+        self._current_state_group = current_state_group
+
+
+class EventCache(object):
+    def __init__(self, store):
+        self._store = store
+
+        self._cache = {}
+
+    @defer.inlineCallbacks
+    def load_event(self, event_id):
+        event = self._cache.get(event_id, None)
+
+        if not event:
+            event = yield self._store.get_event(
+                event_id,
+                allow_none=True
+            )
+
+            if event:
+                self._cache[event_id] = event
+
+        defer.returnValue(event)
+
+    def load_event_from_cache(self, event_id):
+        return self._cache.get(event_id, None)
+
+    def add_to_cache(self, *events):
+        self._cache.update({
+            event.event_id: event
+            for event in events
+        })
+
+
+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/events/utils.py b/synapse/events/utils.py
new file mode 100644
index 0000000000..4ab770dd5f
--- /dev/null
+++ b/synapse/events/utils.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 synapse.api.constants import EventTypes
+from . import EventBase
+
+
+def prune_event(event):
+    """ Returns a pruned version of the given event, which removes all keys we
+    don't know about or think could potentially be dodgy.
+
+    This is used when we "redact" an event. We want to remove all fields that
+    the user has specified, but we do want to keep necessary information like
+    type, state_key etc.
+    """
+    event_type = event.type
+
+    allowed_keys = [
+        "event_id",
+        "sender",
+        "room_id",
+        "hashes",
+        "signatures",
+        "content",
+        "type",
+        "state_key",
+        "depth",
+        "prev_events",
+        "prev_state",
+        "auth_events",
+        "origin",
+        "origin_server_ts",
+    ]
+
+    new_content = {}
+
+    def add_fields(*fields):
+        for field in fields:
+            if field in event.content:
+                new_content[field] = event.content[field]
+
+    if event_type == EventTypes.Member:
+        add_fields("membership")
+    elif event_type == EventTypes.Create:
+        add_fields("creator")
+    elif event_type == EventTypes.JoinRules:
+        add_fields("join_rule")
+    elif event_type == EventTypes.PowerLevels:
+        add_fields(
+            "users",
+            "users_default",
+            "events",
+            "events_default",
+            "events_default",
+            "state_default",
+            "ban",
+            "kick",
+            "redact",
+        )
+    elif event_type == EventTypes.Aliases:
+        add_fields("aliases")
+
+    allowed_fields = {
+        k: v
+        for k, v in event.get_dict().items()
+        if k in allowed_keys
+    }
+
+    allowed_fields["content"] = new_content
+
+    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..47830aa985
--- /dev/null
+++ b/synapse/events/validator.py
@@ -0,0 +1,71 @@
+# -*- 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)
diff --git a/synapse/federation/replication.py b/synapse/federation/replication.py
index 0cb632fb08..6388bb98e2 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
 
@@ -74,6 +75,7 @@ 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 +114,7 @@ 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 +133,7 @@ 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",
@@ -438,7 +440,9 @@ 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 +561,13 @@ 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 +605,7 @@ 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 +668,14 @@ 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
@@ -706,15 +711,13 @@ 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))
 
diff --git a/synapse/handlers/_base.py b/synapse/handlers/_base.py
index 15adc9dc2c..14f75ecbc2 100644
--- a/synapse/handlers/_base.py
+++ b/synapse/handlers/_base.py
@@ -15,11 +15,12 @@
 
 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
+
+from synapse.events.snapshot import EventContext
 
 import logging
 
@@ -31,10 +32,8 @@ 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 +43,8 @@ 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 +58,95 @@ 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)
+        context = EventContext()
+
+        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
+        ret = yield state_handler.annotate_context_with_state(
+            builder,
+            context,
+        )
+        prev_state = ret
 
-        yield self.auth.add_auth_events(event)
+        if builder.is_state():
+            builder.prev_state = prev_state
 
-        logger.debug("Signing event...")
+        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,
         )
 
-        logger.debug("Signed event.")
+        defer.returnValue(
+            (event, context,)
+        )
+
+    @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):
+                    returned_invite = yield federation_handler.send_invite(
+                        invitee.domain,
+                        event,
+                    )
+                    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..76fb897f20 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -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 +148,12 @@ 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)
+        msg_handler = self.hs.get_handlers().message_handler
+        yield msg_handler.handle_event({
+            "type": RoomAliasesEvent.TYPE,
+            "state_key": self.hs.hostname,
+            "room_id": room_id,
+            "sender": user_id,
+            "content": {"aliases": aliases},
+        })
 
-        yield self._on_new_room_event(
-            event, snapshot, extra_users=[user_id], suppress_auth=True
-        )
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index cfb5029774..ddcb28c8e2 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -17,7 +17,8 @@
 
 from ._base import BaseHandler
 
-from synapse.api.events.utils import prune_event
+from synapse.events.snapshot import EventContext
+from synapse.events.utils import prune_event
 from synapse.api.errors import (
     AuthError, FederationError, SynapseError, StoreError,
 )
@@ -76,7 +77,7 @@ 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 +93,7 @@ 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 +136,7 @@ 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 +149,7 @@ 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 +160,7 @@ 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 +180,7 @@ 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:
@@ -265,11 +261,18 @@ class FederationHandler(BaseHandler):
             event = pdu
 
             # FIXME (erikj): Not sure this actually works :/
-            yield self.state_handler.annotate_event_with_state(event)
+            context = EventContext()
+            yield self.state_handler.annotate_context_with_state(event, context)
 
-            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)
 
@@ -286,8 +289,6 @@ class FederationHandler(BaseHandler):
             pdu=event
         )
 
-
-
         defer.returnValue(pdu)
 
     @defer.inlineCallbacks
@@ -337,37 +338,49 @@ class FederationHandler(BaseHandler):
         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(
@@ -380,7 +393,7 @@ 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:
@@ -391,7 +404,7 @@ 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,
@@ -404,13 +417,13 @@ 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)
@@ -419,6 +432,9 @@ 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:
@@ -428,25 +444,24 @@ 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": RoomMemberEvent.TYPE,
+            "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
 
@@ -460,9 +475,21 @@ class FederationHandler(BaseHandler):
         """
         event = pdu
 
-        event.outlier = False
+        logger.debug(
+            "on_send_join_request: Got event: %s, signatures: %s",
+            event.event_id,
+            event.signatures,
+        )
+
+        event.internal_metadata.outlier = False
 
-        yield self._handle_new_event(event)
+        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:
@@ -485,7 +512,7 @@ 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 s.content["membership"] == Membership.JOIN:
@@ -497,14 +524,18 @@ 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,
         })
 
@@ -516,7 +547,9 @@ class FederationHandler(BaseHandler):
         """
         event = pdu
 
-        event.outlier = True
+        context = EventContext()
+
+        event.internal_metadata.outlier = True
 
         event.signatures.update(
             compute_event_signature(
@@ -526,10 +559,11 @@ class FederationHandler(BaseHandler):
             )
         )
 
-        yield self.state_handler.annotate_event_with_state(event)
+        yield self.state_handler.annotate_context_with_state(event, context)
 
         yield self.store.persist_event(
             event,
+            context=context,
             backfilled=False,
         )
 
@@ -559,13 +593,13 @@ 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)]
 
@@ -651,74 +685,80 @@ 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(
+        context = EventContext()
+
+        logger.debug(
+            "_handle_new_event: Before annotate: %s, sigs: %s",
+            event.event_id, event.signatures,
+        )
+
+        yield self.state_handler.annotate_context_with_state(
             event,
+            context,
             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,
-                    )
-
-                    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")
-
-            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,
                     )
+                    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,
+        )
 
-                auth_events[(e.type, e.state_key)] = e
+        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:
+                    context.auth_events[(c.type, c.state_key)] = c
 
-            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
+        logger.debug(
+            "_handle_new_event: Before auth check: %s, sigs: %s",
+            event.event_id, event.signatures,
+        )
 
-        self.auth.check(event, auth_events=auth_events)
+        self.auth.check(event, auth_events=context.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..f92b01a50f 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -15,10 +15,13 @@
 
 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
@@ -33,6 +36,7 @@ class MessageHandler(BaseHandler):
         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,
@@ -79,7 +83,7 @@ class MessageHandler(BaseHandler):
         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,)
+        assert self.hs.is_mine(user), "User must be our own: %s" % (user,)
 
         snapshot = yield self.store.snapshot_room(event)
 
@@ -134,19 +138,36 @@ class MessageHandler(BaseHandler):
         defer.returnValue(chunk)
 
     @defer.inlineCallbacks
-    def store_room_data(self, event=None):
-        """ Stores data for a room.
+    def handle_event(self, event_dict):
+        builder = self.event_builder_factory.new(event_dict)
+
+        self.validator.validate(builder)
+
+        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
+                )
 
-        Args:
-            event : The room path event
-            stamp_event (bool) : True to stamp event content with server keys.
-        Raises:
-            SynapseError if something went wrong.
-        """
+        event, context = yield self._create_new_client_event(
+            builder=builder,
+        )
 
-        snapshot = yield self.store.snapshot_room(event)
+        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,
+            )
 
-        yield self._on_new_room_event(event, snapshot)
+        defer.returnValue(event)
 
     @defer.inlineCallbacks
     def get_room_data(self, user_id=None, room_id=None,
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 84a039489f..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)
 
@@ -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(
diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py
index 814b3b68fe..18fd0914e2 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.handle_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..e771cf317b 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -52,9 +52,9 @@ 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 +76,8 @@ 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 +93,10 @@ 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 +123,37 @@ 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.handle_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.handle_event({
+                "type": RoomNameEvent.TYPE,
+                "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.handle_event({
+                "type": RoomTopicEvent.TYPE,
+                "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.handle_event({
+                "type": RoomMemberEvent.TYPE,
+                "state_key": invitee,
+                "room_id": room_id,
+                "user_id": user_id,
+                "content": {"membership": Membership.INVITE},
+            })
 
         result = {"room_id": room_id}
 
@@ -189,31 +170,35 @@ 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(),
+            content={"creator": creator.to_string()},
         )
 
-        join_event = self.event_factory.create_event(
+        join_event = create(
             etype=RoomMemberEvent.TYPE,
             state_key=creator_id,
             content={
                 "membership": Membership.JOIN,
             },
-            **event_keys
         )
 
-        power_levels_event = self.event_factory.create_event(
+        power_levels_event = create(
             etype=RoomPowerLevelsEvent.TYPE,
             content={
                 "users": {
@@ -230,13 +215,12 @@ 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,
+            content={"join_rule": join_rule},
         )
 
         return [
@@ -287,7 +271,7 @@ 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 +332,7 @@ 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:
@@ -358,9 +342,7 @@ class RoomMemberHandler(BaseHandler):
         """
         target_user_id = event.state_key
 
-        snapshot = yield self.store.snapshot_room(event)
-
-        ## TODO(markjh): get prev state from snapshot.
+        # TODO(markjh): get prev state from snapshot.
         prev_state = yield self.store.get_room_member(
             target_user_id, event.room_id
         )
@@ -371,10 +353,11 @@ 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({})
@@ -383,7 +366,7 @@ class RoomMemberHandler(BaseHandler):
             yield self._do_local_membership_update(
                 event,
                 membership=event.content["membership"],
-                snapshot=snapshot,
+                context=context,
                 do_auth=do_auth,
             )
 
@@ -405,32 +388,26 @@ 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": RoomMemberEvent.TYPE,
+            "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 +429,29 @@ 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 +476,10 @@ 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 +501,17 @@ 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..be67fb2fc2 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -47,7 +47,7 @@ class TypingNotificationHandler(BaseHandler):
 
     @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:
@@ -72,7 +72,7 @@ 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:
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..72bb66ddda 100644
--- a/synapse/rest/base.py
+++ b/synapse/rest/base.py
@@ -63,7 +63,7 @@ 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()
 
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..062c895595 100644
--- a/synapse/rest/presence.py
+++ b/synapse/rest/presence.py
@@ -83,7 +83,7 @@ class PresenceListRestServlet(RestServlet):
         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:
@@ -104,7 +104,7 @@ class PresenceListRestServlet(RestServlet):
         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/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..c526e9bc72 100644
--- a/synapse/rest/room.py
+++ b/synapse/rest/room.py
@@ -147,28 +147,20 @@ class RoomStateEventRestServlet(RestServlet):
 
         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": urllib.unquote(room_id),
+            "sender": user.to_string(),
+        }
 
-        self.validator.validate(event)
+        if state_key is not None:
+            event_dict["state_key"] = urllib.unquote(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.handle_event(event_dict)
+
+        defer.returnValue((200, {}))
 
 
 # TODO: Needs unit testing for generic events + feedback
@@ -184,17 +176,15 @@ 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.handle_event(
+            {
+                "type": urllib.unquote(event_type),
+                "content": content,
+                "room_id": urllib.unquote(room_id),
+                "sender": user.to_string(),
+            }
+        )
 
         defer.returnValue((200, {"event_id": event.event_id}))
 
@@ -251,18 +241,17 @@ 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.handle_event(
+                {
+                    "type": RoomMemberEvent.TYPE,
+                    "content": {"membership": Membership.JOIN},
+                    "room_id": urllib.unquote(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
@@ -414,18 +403,17 @@ 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.handle_event(
+            {
+                "type": RoomMemberEvent.TYPE,
+                "content": {"membership": unicode(membership_action)},
+                "room_id": urllib.unquote(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 +441,16 @@ 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.handle_event(
+            {
+                "type": RoomRedactionEvent.TYPE,
+                "content": content,
+                "room_id": urllib.unquote(room_id),
+                "sender": user.to_string(),
+                "redacts": urllib.unquote(event_id),
+            }
+        )
 
         defer.returnValue((200, {"event_id": event.event_id}))
 
diff --git a/synapse/server.py b/synapse/server.py
index 7eb15270fc..1c0703c51f 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -20,7 +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.events.utils import serialize_event
 from synapse.api.events.factory import EventFactory
 from synapse.api.events.validator import EventValidator
 from synapse.notifier import Notifier
@@ -36,6 +36,7 @@ from synapse.util.lockutils import LockManager
 from synapse.streams.events import EventSources
 from synapse.api.ratelimiting import Ratelimiter
 from synapse.crypto.keyring import Keyring
+from synapse.events.builder import EventBuilderFactory
 
 
 class BaseHomeServer(object):
@@ -83,6 +84,7 @@ class BaseHomeServer(object):
         'ratelimiter',
         'keyring',
         'event_validator',
+        'event_builder_factory',
     ]
 
     def __init__(self, hostname, **kwargs):
@@ -134,22 +136,22 @@ 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)
@@ -166,6 +168,9 @@ 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)
@@ -229,6 +234,12 @@ class HomeServer(BaseHomeServer):
     def build_event_validator(self):
         return EventValidator(self)
 
+    def build_event_builder_factory(self):
+        return EventBuilderFactory(
+            clock=self.get_clock(),
+            hostname=self.hostname,
+        )
+
     def register_servlets(self):
         """ Register all servlets associated with this HomeServer.
         """
diff --git a/synapse/state.py b/synapse/state.py
index 430665f7ba..f9ab5faf9e 100644
--- a/synapse/state.py
+++ b/synapse/state.py
@@ -89,7 +89,7 @@ class StateHandler(object):
         ids = [e for e, _ in event.prev_events]
 
         ret = yield self.resolve_state_groups(ids)
-        state_group, new_state = ret
+        state_group, new_state, _ = ret
 
         event.old_state_events = copy.deepcopy(new_state)
 
@@ -136,8 +136,75 @@ class StateHandler(object):
         defer.returnValue(res[1].values())
 
     @defer.inlineCallbacks
+    def annotate_context_with_state(self, event, context, old_state=None):
+        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
+
+            defer.returnValue([])
+
+        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 = {}
+
+        defer.returnValue(prev_state)
+
+    @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 +223,14 @@ 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 +251,13 @@ class StateHandler(object):
             if len(v.values()) > 1
         }
 
+        if event_type:
+            prev_states = conflicted_state.get(
+                (event_type, state_key), {}
+            ).keys()
+        else:
+            prev_states = []
+
         try:
             new_state = {}
             new_state.update(unconflicted_state)
@@ -186,7 +267,7 @@ 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:
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index c9ab434b4e..3bc3622169 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -21,6 +21,7 @@ from synapse.api.events.room import (
 )
 
 from synapse.util.logutils import log_function
+from synapse.util.frozenutils import FrozenEncoder
 
 from .directory import DirectoryStore
 from .feedback import FeedbackStore
@@ -39,6 +40,7 @@ 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
 
@@ -97,8 +99,8 @@ 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:
@@ -111,6 +113,7 @@ 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,
@@ -121,29 +124,20 @@ 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):
+    def _persist_event_txn(self, txn, event, context, backfilled,
+                           stream_ordering=None, is_new_state=True,
+                           current_state=None):
         if event.type == RoomMemberEvent.TYPE:
             self._store_room_member_txn(txn, event)
         elif event.type == FeedbackEvent.TYPE:
@@ -156,15 +150,35 @@ class DataStore(RoomMemberStore, RoomStore,
             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",
+            ]
+        }
+
+        self._simple_insert_txn(
+            txn,
+            table="event_json",
+            values={
+                "event_id": event.event_id,
+                "room_id": event.room_id,
+                "json": encode_canonical_json(event_dict),
+            },
+            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.content, cls=FrozenEncoder),
             "processed": True,
             "outlier": outlier,
             "depth": event.depth,
@@ -175,7 +189,7 @@ 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",
@@ -210,7 +224,8 @@ 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(
@@ -304,16 +319,6 @@ 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)
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index e72200e2f7..b6f8817b62 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -15,10 +15,10 @@
 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
 
@@ -436,123 +436,76 @@ 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 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)
+        js, redacted = res
 
-    def _parse_events(self, rows):
-        return self.runInteraction(
-            "_parse_events", self._parse_events_txn, rows
-        )
+        d = json.loads(js)
 
-    def _parse_events_txn(self, txn, rows):
-        events = [self._parse_event_from_row(r) for r in rows]
+        ev = FrozenEvent(d)
 
-        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 = ?"
diff --git a/synapse/storage/schema/im.sql b/synapse/storage/schema/im.sql
index 8ba732a23b..0300bb29e1 100644
--- a/synapse/storage/schema/im.sql
+++ b/synapse/storage/schema/im.sql
@@ -32,6 +32,18 @@ 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,
+    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/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/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/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..1fb67df6b9
--- /dev/null
+++ b/synapse/util/frozenutils.py
@@ -0,0 +1,56 @@
+# -*- 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
+
+import json
+
+
+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
+
+
+class FrozenEncoder(json.JSONEncoder):
+    def default(self, o):
+        if isinstance(o, frozendict):
+            return dict(o)
+
+        return json.JSONEncoder(self, o)
diff --git a/tests/federation/test_federation.py b/tests/federation/test_federation.py
index f6b41e2c4c..79ac1ce10d 100644
--- a/tests/federation/test_federation.py
+++ b/tests/federation/test_federation.py
@@ -23,25 +23,20 @@ from ..utils import MockHttpResource, MockClock, MockKey
 
 from synapse.server import HomeServer
 from synapse.federation import initialize_http_replication
-from synapse.api.events import SynapseEvent
+from synapse.events import FrozenEvent
 
 from synapse.storage.transactions import DestinationsTable
 
+
 def make_pdu(prev_pdus=[], **kwargs):
     """Provide some default fields for making a PduTuple."""
     pdu_fields = {
-        "is_state": False,
-        "unrecognized_keys": [],
-        "outlier": False,
-        "have_processed": True,
         "state_key": None,
-        "power_level": None,
-        "prev_state_id": None,
-        "prev_state_origin": None,
+        "prev_events": prev_pdus,
     }
     pdu_fields.update(kwargs)
 
-    return SynapseEvent(prev_pdus=prev_pdus, **pdu_fields)
+    return FrozenEvent(pdu_fields)
 
 
 class FederationTestCase(unittest.TestCase):
@@ -176,7 +171,7 @@ class FederationTestCase(unittest.TestCase):
             (200, "OK")
         )
 
-        pdu = SynapseEvent(
+        pdu = make_pdu(
             event_id="abc123def456",
             origin="red",
             user_id="@a:red",
@@ -185,10 +180,9 @@ class FederationTestCase(unittest.TestCase):
             origin_server_ts=123456789001,
             depth=1,
             content={"text": "Here is the message"},
-            destinations=["remote"],
         )
 
-        yield self.federation.send_pdu(pdu)
+        yield self.federation.send_pdu(pdu, ["remote"])
 
         self.mock_http_client.put_json.assert_called_with(
             "remote",
diff --git a/tests/handlers/test_federation.py b/tests/handlers/test_federation.py
index fae33716a3..91f7351087 100644
--- a/tests/handlers/test_federation.py
+++ b/tests/handlers/test_federation.py
@@ -20,7 +20,7 @@ from synapse.api.events.room import (
     MessageEvent,
 )
 
-from synapse.api.events import SynapseEvent
+from synapse.events import FrozenEvent
 from synapse.handlers.federation import FederationHandler
 from synapse.server import HomeServer
 
@@ -37,7 +37,7 @@ class FederationTestCase(unittest.TestCase):
         self.mock_config.signing_key = [MockKey()]
 
         self.state_handler = NonCallableMock(spec_set=[
-            "annotate_event_with_state",
+            "annotate_context_with_state",
         ])
 
         self.auth = NonCallableMock(spec_set=[
@@ -78,36 +78,42 @@ class FederationTestCase(unittest.TestCase):
 
     @defer.inlineCallbacks
     def test_msg(self):
-        pdu = SynapseEvent(
-            type=MessageEvent.TYPE,
-            room_id="foo",
-            content={"msgtype": u"fooo"},
-            origin_server_ts=0,
-            event_id="$a:b",
-            user_id="@a:b",
-            origin="b",
-            auth_events=[],
-            hashes={"sha256":"AcLrgtUIqqwaGoHhrEvYG1YLDIsVPYJdSRGhkp3jJp8"},
-        )
+        pdu = FrozenEvent({
+            "type": MessageEvent.TYPE,
+            "room_id": "foo",
+            "content": {"msgtype": u"fooo"},
+            "origin_server_ts": 0,
+            "event_id": "$a:b",
+            "user_id":"@a:b",
+            "origin": "b",
+            "auth_events": [],
+            "hashes": {"sha256":"AcLrgtUIqqwaGoHhrEvYG1YLDIsVPYJdSRGhkp3jJp8"},
+        })
 
         self.datastore.persist_event.return_value = defer.succeed(None)
         self.datastore.get_room.return_value = defer.succeed(True)
         self.auth.check_host_in_room.return_value = defer.succeed(True)
 
-        def annotate(ev, old_state=None):
-            ev.old_state_events = []
+        def annotate(ev, context, old_state=None):
+            context.current_state = {}
+            context.auth_events = {}
             return defer.succeed(False)
-        self.state_handler.annotate_event_with_state.side_effect = annotate
+        self.state_handler.annotate_context_with_state.side_effect = annotate
 
         yield self.handlers.federation_handler.on_receive_pdu(
             "fo", pdu, False
         )
 
         self.datastore.persist_event.assert_called_once_with(
-            ANY, is_new_state=False, backfilled=False, current_state=None
+            ANY,
+            is_new_state=True,
+            backfilled=False,
+            current_state=None,
+            context=ANY,
         )
 
-        self.state_handler.annotate_event_with_state.assert_called_once_with(
+        self.state_handler.annotate_context_with_state.assert_called_once_with(
+            ANY,
             ANY,
             old_state=None,
         )
diff --git a/tests/handlers/test_room.py b/tests/handlers/test_room.py
index 0279ab703a..1e6e7c3602 100644
--- a/tests/handlers/test_room.py
+++ b/tests/handlers/test_room.py
@@ -20,7 +20,7 @@ from tests import unittest
 from synapse.api.events.room import (
     RoomMemberEvent,
 )
-from synapse.api.constants import Membership
+from synapse.api.constants import EventTypes, Membership
 from synapse.handlers.room import RoomMemberHandler, RoomCreationHandler
 from synapse.handlers.profile import ProfileHandler
 from synapse.server import HomeServer
@@ -254,13 +254,9 @@ class RoomCreationTest(unittest.TestCase):
             notifier=NonCallableMock(spec_set=["on_new_room_event"]),
             handlers=NonCallableMock(spec_set=[
                 "room_creation_handler",
-                "room_member_handler",
-                "federation_handler",
+                "message_handler",
             ]),
             auth=NonCallableMock(spec_set=["check", "add_auth_events"]),
-            state_handler=NonCallableMock(spec_set=[
-                "annotate_event_with_state",
-            ]),
             ratelimiter=NonCallableMock(spec_set=[
                 "send_message",
             ]),
@@ -271,30 +267,12 @@ class RoomCreationTest(unittest.TestCase):
             "handle_new_event",
         ])
 
-        self.datastore = hs.get_datastore()
         self.handlers = hs.get_handlers()
-        self.notifier = hs.get_notifier()
-        self.state_handler = hs.get_state_handler()
-        self.hs = hs
-
-        self.handlers.federation_handler = self.federation
 
-        self.handlers.room_creation_handler = RoomCreationHandler(self.hs)
+        self.handlers.room_creation_handler = RoomCreationHandler(hs)
         self.room_creation_handler = self.handlers.room_creation_handler
 
-        self.handlers.room_member_handler = NonCallableMock(spec_set=[
-            "change_membership"
-        ])
-        self.room_member_handler = self.handlers.room_member_handler
-
-        def annotate(event):
-            event.state_events = {}
-            return defer.succeed(None)
-        self.state_handler.annotate_event_with_state.side_effect = annotate
-
-        def hosts(room):
-            return defer.succeed([])
-        self.datastore.get_joined_hosts_for_room.side_effect = hosts
+        self.message_handler = self.handlers.message_handler
 
         self.ratelimiter = hs.get_ratelimiter()
         self.ratelimiter.send_message.return_value = (True, 0)
@@ -311,14 +289,36 @@ class RoomCreationTest(unittest.TestCase):
             config=config,
         )
 
-        self.assertTrue(self.room_member_handler.change_membership.called)
-        join_event = self.room_member_handler.change_membership.call_args[0][0]
+        self.assertTrue(self.message_handler.handle_event.called)
+
+        event_dicts = [
+            e[0][0] for e in self.message_handler.handle_event.call_args_list
+        ]
 
-        self.assertEquals(RoomMemberEvent.TYPE, join_event.type)
-        self.assertEquals(room_id, join_event.room_id)
-        self.assertEquals(user_id, join_event.user_id)
-        self.assertEquals(user_id, join_event.state_key)
+        self.assertTrue(len(event_dicts) > 3)
 
-        self.assertTrue(self.state_handler.annotate_event_with_state.called)
+        self.assertDictContainsSubset(
+            {
+                "type": EventTypes.Create,
+                "sender": user_id,
+                "room_id": room_id,
+            },
+            event_dicts[0]
+        )
+
+        self.assertEqual(user_id, event_dicts[0]["content"]["creator"])
 
-        self.assertTrue(self.federation.handle_new_event.called)
+        self.assertDictContainsSubset(
+            {
+                "type": EventTypes.Member,
+                "sender": user_id,
+                "room_id": room_id,
+                "state_key": user_id,
+            },
+            event_dicts[1]
+        )
+
+        self.assertEqual(
+            Membership.JOIN,
+            event_dicts[1]["content"]["membership"]
+        )
diff --git a/tests/handlers/test_typing.py b/tests/handlers/test_typing.py
index 7e6ed9a42f..af466c474f 100644
--- a/tests/handlers/test_typing.py
+++ b/tests/handlers/test_typing.py
@@ -131,7 +131,7 @@ class TypingNotificationsTestCase(unittest.TestCase):
                 if ignore_user is not None and member == ignore_user:
                     continue
 
-                if member.is_mine:
+                if hs.is_mine(member):
                     if localusers is not None:
                         localusers.add(member)
                 else:
diff --git a/tests/storage/test_redaction.py b/tests/storage/test_redaction.py
index adfe64a980..f670e154c3 100644
--- a/tests/storage/test_redaction.py
+++ b/tests/storage/test_redaction.py
@@ -23,7 +23,9 @@ from synapse.api.events.room import (
     RoomMemberEvent, MessageEvent, RoomRedactionEvent,
 )
 
-from tests.utils import SQLiteMemoryDbPool
+from tests.utils import SQLiteMemoryDbPool, MockKey
+
+from mock import Mock
 
 
 class RedactionTestCase(unittest.TestCase):
@@ -33,13 +35,21 @@ class RedactionTestCase(unittest.TestCase):
         db_pool = SQLiteMemoryDbPool()
         yield db_pool.prepare()
 
+        self.mock_config = Mock()
+        self.mock_config.signing_key = [MockKey()]
+
         hs = HomeServer(
             "test",
             db_pool=db_pool,
+            config=self.mock_config,
+            resource_for_federation=Mock(),
+            http_client=None,
         )
 
         self.store = hs.get_datastore()
-        self.event_factory = hs.get_event_factory()
+        self.event_builder_factory = hs.get_event_builder_factory()
+        self.handlers = hs.get_handlers()
+        self.message_handler = self.handlers.message_handler
 
         self.u_alice = hs.parse_userid("@alice:test")
         self.u_bob = hs.parse_userid("@bob:test")
@@ -49,35 +59,23 @@ class RedactionTestCase(unittest.TestCase):
         self.depth = 1
 
     @defer.inlineCallbacks
-    def inject_room_member(self, room, user, membership, prev_state=None,
+    def inject_room_member(self, room, user, membership, replaces_state=None,
                            extra_content={}):
-        self.depth += 1
-
-        event = self.event_factory.create_event(
-            etype=RoomMemberEvent.TYPE,
-            user_id=user.to_string(),
-            state_key=user.to_string(),
-            room_id=room.to_string(),
-            membership=membership,
-            content={"membership": membership},
-            depth=self.depth,
-            prev_events=[],
+        content = {"membership": membership}
+        content.update(extra_content)
+        builder = self.event_builder_factory.new({
+            "type": RoomMemberEvent.TYPE,
+            "sender": user.to_string(),
+            "state_key": user.to_string(),
+            "room_id": room.to_string(),
+            "content": content,
+        })
+
+        event, context = yield self.message_handler._create_new_client_event(
+            builder
         )
 
-        event.content.update(extra_content)
-
-        if prev_state:
-            event.prev_state = prev_state
-
-        event.state_events = None
-        event.hashes = {}
-        event.prev_state = []
-        event.auth_events = []
-
-        # Have to create a join event using the eventfactory
-        yield self.store.persist_event(
-            event
-        )
+        yield self.store.persist_event(event, context)
 
         defer.returnValue(event)
 
@@ -85,46 +83,38 @@ class RedactionTestCase(unittest.TestCase):
     def inject_message(self, room, user, body):
         self.depth += 1
 
-        event = self.event_factory.create_event(
-            etype=MessageEvent.TYPE,
-            user_id=user.to_string(),
-            room_id=room.to_string(),
-            content={"body": body, "msgtype": u"message"},
-            depth=self.depth,
-            prev_events=[],
-        )
+        builder = self.event_builder_factory.new({
+            "type": MessageEvent.TYPE,
+            "sender": user.to_string(),
+            "state_key": user.to_string(),
+            "room_id": room.to_string(),
+            "content": {"body": body, "msgtype": u"message"},
+        })
 
-        event.state_events = None
-        event.hashes = {}
-        event.auth_events = []
-
-        yield self.store.persist_event(
-            event
+        event, context = yield self.message_handler._create_new_client_event(
+            builder
         )
 
+        yield self.store.persist_event(event, context)
+
         defer.returnValue(event)
 
     @defer.inlineCallbacks
     def inject_redaction(self, room, event_id, user, reason):
-        event = self.event_factory.create_event(
-            etype=RoomRedactionEvent.TYPE,
-            user_id=user.to_string(),
-            room_id=room.to_string(),
-            content={"reason": reason},
-            depth=self.depth,
-            redacts=event_id,
-            prev_events=[],
+        builder = self.event_builder_factory.new({
+            "type": RoomRedactionEvent.TYPE,
+            "sender": user.to_string(),
+            "state_key": user.to_string(),
+            "room_id": room.to_string(),
+            "content": {"reason": reason},
+            "redacts": event_id,
+        })
+
+        event, context = yield self.message_handler._create_new_client_event(
+            builder
         )
 
-        event.state_events = None
-        event.hashes = {}
-        event.auth_events = []
-
-        yield self.store.persist_event(
-            event
-        )
-
-        defer.returnValue(event)
+        yield self.store.persist_event(event, context)
 
     @defer.inlineCallbacks
     def test_redact(self):
@@ -159,7 +149,7 @@ class RedactionTestCase(unittest.TestCase):
             event,
         )
 
-        self.assertFalse(hasattr(event, "redacted_because"))
+        self.assertFalse("redacted_because" in event.unsigned)
 
         # Redact event
         reason = "Because I said so"
@@ -180,6 +170,10 @@ class RedactionTestCase(unittest.TestCase):
 
         event = results[0]
 
+        self.assertEqual(msg_event.event_id, event.event_id)
+
+        self.assertTrue("redacted_because" in event.unsigned)
+
         self.assertObjectHasAttributes(
             {
                 "type": MessageEvent.TYPE,
@@ -189,15 +183,13 @@ class RedactionTestCase(unittest.TestCase):
             event,
         )
 
-        self.assertTrue(hasattr(event, "redacted_because"))
-
         self.assertObjectHasAttributes(
             {
                 "type": RoomRedactionEvent.TYPE,
                 "user_id": self.u_alice.to_string(),
                 "content": {"reason": reason},
             },
-            event.redacted_because,
+            event.unsigned["redacted_because"],
         )
 
     @defer.inlineCallbacks
@@ -257,6 +249,8 @@ class RedactionTestCase(unittest.TestCase):
 
         event = results[0]
 
+        self.assertTrue("redacted_because" in event.unsigned)
+
         self.assertObjectHasAttributes(
             {
                 "type": RoomMemberEvent.TYPE,
@@ -266,13 +260,11 @@ class RedactionTestCase(unittest.TestCase):
             event,
         )
 
-        self.assertTrue(hasattr(event, "redacted_because"))
-
         self.assertObjectHasAttributes(
             {
                 "type": RoomRedactionEvent.TYPE,
                 "user_id": self.u_alice.to_string(),
                 "content": {"reason": reason},
             },
-            event.redacted_because,
+            event.unsigned["redacted_because"],
         )
diff --git a/tests/storage/test_roommember.py b/tests/storage/test_roommember.py
index 8614e5ca9d..6df09952d1 100644
--- a/tests/storage/test_roommember.py
+++ b/tests/storage/test_roommember.py
@@ -21,7 +21,9 @@ from synapse.server import HomeServer
 from synapse.api.constants import Membership
 from synapse.api.events.room import RoomMemberEvent
 
-from tests.utils import SQLiteMemoryDbPool
+from tests.utils import SQLiteMemoryDbPool, MockKey
+
+from mock import Mock
 
 
 class RoomMemberStoreTestCase(unittest.TestCase):
@@ -31,14 +33,22 @@ class RoomMemberStoreTestCase(unittest.TestCase):
         db_pool = SQLiteMemoryDbPool()
         yield db_pool.prepare()
 
-        hs = HomeServer("test",
+        self.mock_config = Mock()
+        self.mock_config.signing_key = [MockKey()]
+
+        hs = HomeServer(
+            "test",
             db_pool=db_pool,
+            config=self.mock_config,
+            resource_for_federation=Mock(),
+            http_client=None,
         )
-
         # We can't test the RoomMemberStore on its own without the other event
         # storage logic
         self.store = hs.get_datastore()
-        self.event_factory = hs.get_event_factory()
+        self.event_builder_factory = hs.get_event_builder_factory()
+        self.handlers = hs.get_handlers()
+        self.message_handler = self.handlers.message_handler
 
         self.u_alice = hs.parse_userid("@alice:test")
         self.u_bob = hs.parse_userid("@bob:test")
@@ -49,27 +59,22 @@ class RoomMemberStoreTestCase(unittest.TestCase):
         self.room = hs.parse_roomid("!abc123:test")
 
     @defer.inlineCallbacks
-    def inject_room_member(self, room, user, membership):
-        # Have to create a join event using the eventfactory
-        event = self.event_factory.create_event(
-            etype=RoomMemberEvent.TYPE,
-            user_id=user.to_string(),
-            state_key=user.to_string(),
-            room_id=room.to_string(),
-            membership=membership,
-            content={"membership": membership},
-            depth=1,
-            prev_events=[],
+    def inject_room_member(self, room, user, membership, replaces_state=None):
+        builder = self.event_builder_factory.new({
+            "type": RoomMemberEvent.TYPE,
+            "sender": user.to_string(),
+            "state_key": user.to_string(),
+            "room_id": room.to_string(),
+            "content": {"membership": membership},
+        })
+
+        event, context = yield self.message_handler._create_new_client_event(
+            builder
         )
 
-        event.state_events = None
-        event.hashes = {}
-        event.prev_state = {}
-        event.auth_events = {}
+        yield self.store.persist_event(event, context)
 
-        yield self.store.persist_event(
-            event
-        )
+        defer.returnValue(event)
 
     @defer.inlineCallbacks
     def test_one_member(self):
diff --git a/tests/storage/test_stream.py b/tests/storage/test_stream.py
index 5038546aee..4865a5c142 100644
--- a/tests/storage/test_stream.py
+++ b/tests/storage/test_stream.py
@@ -21,7 +21,9 @@ from synapse.server import HomeServer
 from synapse.api.constants import Membership
 from synapse.api.events.room import RoomMemberEvent, MessageEvent
 
-from tests.utils import SQLiteMemoryDbPool
+from tests.utils import SQLiteMemoryDbPool, MockKey
+
+from mock import Mock
 
 
 class StreamStoreTestCase(unittest.TestCase):
@@ -31,13 +33,21 @@ class StreamStoreTestCase(unittest.TestCase):
         db_pool = SQLiteMemoryDbPool()
         yield db_pool.prepare()
 
+        self.mock_config = Mock()
+        self.mock_config.signing_key = [MockKey()]
+
         hs = HomeServer(
             "test",
             db_pool=db_pool,
+            config=self.mock_config,
+            resource_for_federation=Mock(),
+            http_client=None,
         )
 
         self.store = hs.get_datastore()
-        self.event_factory = hs.get_event_factory()
+        self.event_builder_factory = hs.get_event_builder_factory()
+        self.handlers = hs.get_handlers()
+        self.message_handler = self.handlers.message_handler
 
         self.u_alice = hs.parse_userid("@alice:test")
         self.u_bob = hs.parse_userid("@bob:test")
@@ -48,58 +58,43 @@ class StreamStoreTestCase(unittest.TestCase):
         self.depth = 1
 
     @defer.inlineCallbacks
-    def inject_room_member(self, room, user, membership, replaces_state=None):
+    def inject_room_member(self, room, user, membership):
         self.depth += 1
 
-        event = self.event_factory.create_event(
-            etype=RoomMemberEvent.TYPE,
-            user_id=user.to_string(),
-            state_key=user.to_string(),
-            room_id=room.to_string(),
-            membership=membership,
-            content={"membership": membership},
-            depth=self.depth,
-            prev_events=[],
-        )
-
-        event.state_events = None
-        event.hashes = {}
-        event.prev_state = []
-        event.auth_events = []
-
-        if replaces_state:
-            event.prev_state = [(replaces_state, "hash")]
-            event.replaces_state = replaces_state
+        builder = self.event_builder_factory.new({
+            "type": RoomMemberEvent.TYPE,
+            "sender": user.to_string(),
+            "state_key": user.to_string(),
+            "room_id": room.to_string(),
+            "content": {"membership": membership},
+        })
 
-        # Have to create a join event using the eventfactory
-        yield self.store.persist_event(
-            event
+        event, context = yield self.message_handler._create_new_client_event(
+            builder
         )
 
+        yield self.store.persist_event(event, context)
+
         defer.returnValue(event)
 
     @defer.inlineCallbacks
     def inject_message(self, room, user, body):
         self.depth += 1
 
-        event = self.event_factory.create_event(
-            etype=MessageEvent.TYPE,
-            user_id=user.to_string(),
-            room_id=room.to_string(),
-            content={"body": body, "msgtype": u"message"},
-            depth=self.depth,
-            prev_events=[],
-        )
-
-        event.state_events = None
-        event.hashes = {}
-        event.auth_events = []
+        builder = self.event_builder_factory.new({
+            "type": MessageEvent.TYPE,
+            "sender": user.to_string(),
+            "state_key": user.to_string(),
+            "room_id": room.to_string(),
+            "content": {"body": body, "msgtype": u"message"},
+        })
 
-        # Have to create a join event using the eventfactory
-        yield self.store.persist_event(
-            event
+        event, context = yield self.message_handler._create_new_client_event(
+            builder
         )
 
+        yield self.store.persist_event(event, context)
+
     @defer.inlineCallbacks
     def test_event_stream_get_other(self):
         # Both bob and alice joins the room
@@ -220,7 +215,6 @@ class StreamStoreTestCase(unittest.TestCase):
 
         event2 = yield self.inject_room_member(
             self.room1, self.u_alice, Membership.JOIN,
-            replaces_state=event1.event_id,
         )
 
         end = yield self.store.get_room_events_max_id()
@@ -238,6 +232,6 @@ class StreamStoreTestCase(unittest.TestCase):
         event = results[0]
 
         self.assertTrue(
-            hasattr(event, "prev_content"),
+            "prev_content" in event.unsigned,
             msg="No prev_content key"
         )
diff --git a/tests/test_types.py b/tests/test_types.py
index 276ecc91fd..bfb9e6f548 100644
--- a/tests/test_types.py
+++ b/tests/test_types.py
@@ -23,21 +23,21 @@ mock_homeserver = BaseHomeServer(hostname="my.domain")
 class UserIDTestCase(unittest.TestCase):
 
     def test_parse(self):
-        user = UserID.from_string("@1234abcd:my.domain", hs=mock_homeserver)
+        user = UserID.from_string("@1234abcd:my.domain")
 
         self.assertEquals("1234abcd", user.localpart)
         self.assertEquals("my.domain", user.domain)
-        self.assertEquals(True, user.is_mine)
+        self.assertEquals(True, mock_homeserver.is_mine(user))
 
     def test_build(self):
-        user = UserID("5678efgh", "my.domain", True)
+        user = UserID("5678efgh", "my.domain")
 
         self.assertEquals(user.to_string(), "@5678efgh:my.domain")
 
     def test_compare(self):
-        userA = UserID.from_string("@userA:my.domain", hs=mock_homeserver)
-        userAagain = UserID.from_string("@userA:my.domain", hs=mock_homeserver)
-        userB = UserID.from_string("@userB:my.domain", hs=mock_homeserver)
+        userA = UserID.from_string("@userA:my.domain")
+        userAagain = UserID.from_string("@userA:my.domain")
+        userB = UserID.from_string("@userB:my.domain")
 
         self.assertTrue(userA == userAagain)
         self.assertTrue(userA != userB)
@@ -52,14 +52,14 @@ class UserIDTestCase(unittest.TestCase):
 class RoomAliasTestCase(unittest.TestCase):
 
     def test_parse(self):
-        room = RoomAlias.from_string("#channel:my.domain", hs=mock_homeserver)
+        room = RoomAlias.from_string("#channel:my.domain")
 
         self.assertEquals("channel", room.localpart)
         self.assertEquals("my.domain", room.domain)
-        self.assertEquals(True, room.is_mine)
+        self.assertEquals(True, mock_homeserver.is_mine(room))
 
     def test_build(self):
-        room = RoomAlias("channel", "my.domain", True)
+        room = RoomAlias("channel", "my.domain")
 
         self.assertEquals(room.to_string(), "#channel:my.domain")