Merge pull request #199 from matrix-org/erikj/receipts

Implement read receipts.

16 files changed, 701 insertions, 35 deletions

diff --git a/synapse/handlers/__init__.py b/synapse/handlers/__init__.py
index 685792dbdc..dc5b6ef79d 100644
--- a/synapse/handlers/__init__.py
+++ b/synapse/handlers/__init__.py
@@ -32,6 +32,7 @@ from .appservice import ApplicationServicesHandler
 from .sync import SyncHandler
 from .auth import AuthHandler
 from .identity import IdentityHandler
+from .receipts import ReceiptsHandler
 
 
 class Handlers(object):
@@ -57,6 +58,7 @@ class Handlers(object):
         self.directory_handler = DirectoryHandler(hs)
         self.typing_notification_handler = TypingNotificationHandler(hs)
         self.admin_handler = AdminHandler(hs)
+        self.receipts_handler = ReceiptsHandler(hs)
         asapi = ApplicationServiceApi(hs)
         self.appservice_handler = ApplicationServicesHandler(
             hs, asapi, AppServiceScheduler(
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index d8b117612d..9d6d4f0978 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -334,6 +334,11 @@ class MessageHandler(BaseHandler):
             user, pagination_config.get_source_config("presence"), None
         )
 
+        receipt_stream = self.hs.get_event_sources().sources["receipt"]
+        receipt, _ = yield receipt_stream.get_pagination_rows(
+            user, pagination_config.get_source_config("receipt"), None
+        )
+
         public_room_ids = yield self.store.get_public_room_ids()
 
         limit = pagin_config.limit
@@ -404,7 +409,8 @@ class MessageHandler(BaseHandler):
         ret = {
             "rooms": rooms_ret,
             "presence": presence,
-            "end": now_token.to_string()
+            "receipts": receipt,
+            "end": now_token.to_string(),
         }
 
         defer.returnValue(ret)
@@ -465,9 +471,12 @@ class MessageHandler(BaseHandler):
 
             defer.returnValue([p for success, p in presence_defs if success])
 
-        presence, (messages, token) = yield defer.gatherResults(
+        receipts_handler = self.hs.get_handlers().receipts_handler
+
+        presence, receipts, (messages, token) = yield defer.gatherResults(
             [
                 get_presence(),
+                receipts_handler.get_receipts_for_room(room_id, now_token.receipt_key),
                 self.store.get_recent_events_for_room(
                     room_id,
                     limit=limit,
@@ -495,5 +504,6 @@ class MessageHandler(BaseHandler):
                 "end": end_token.to_string(),
             },
             "state": state,
-            "presence": presence
+            "presence": presence,
+            "receipts": receipts,
         })
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 7c03198313..341a516da2 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -992,7 +992,7 @@ class PresenceHandler(BaseHandler):
             room_ids([str]): List of room_ids to notify.
         """
         with PreserveLoggingContext():
-            self.notifier.on_new_user_event(
+            self.notifier.on_new_event(
                 "presence_key",
                 self._user_cachemap_latest_serial,
                 users_to_push,
diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
new file mode 100644
index 0000000000..5b3df6932b
--- /dev/null
+++ b/synapse/handlers/receipts.py
@@ -0,0 +1,207 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from ._base import BaseHandler
+
+from twisted.internet import defer
+
+from synapse.util.logcontext import PreserveLoggingContext
+
+import logging
+
+
+logger = logging.getLogger(__name__)
+
+
+class ReceiptsHandler(BaseHandler):
+    def __init__(self, hs):
+        super(ReceiptsHandler, self).__init__(hs)
+
+        self.hs = hs
+        self.federation = hs.get_replication_layer()
+        self.federation.register_edu_handler(
+            "m.receipt", self._received_remote_receipt
+        )
+        self.clock = self.hs.get_clock()
+
+        self._receipt_cache = None
+
+    @defer.inlineCallbacks
+    def received_client_receipt(self, room_id, receipt_type, user_id,
+                                event_id):
+        """Called when a client tells us a local user has read up to the given
+        event_id in the room.
+        """
+        receipt = {
+            "room_id": room_id,
+            "receipt_type": receipt_type,
+            "user_id": user_id,
+            "event_ids": [event_id],
+            "data": {
+                "ts": int(self.clock.time_msec()),
+            }
+        }
+
+        is_new = yield self._handle_new_receipts([receipt])
+
+        if is_new:
+            self._push_remotes([receipt])
+
+    @defer.inlineCallbacks
+    def _received_remote_receipt(self, origin, content):
+        """Called when we receive an EDU of type m.receipt from a remote HS.
+        """
+        receipts = [
+            {
+                "room_id": room_id,
+                "receipt_type": receipt_type,
+                "user_id": user_id,
+                "event_ids": user_values["event_ids"],
+                "data": user_values.get("data", {}),
+            }
+            for room_id, room_values in content.items()
+            for receipt_type, users in room_values.items()
+            for user_id, user_values in users.items()
+        ]
+
+        yield self._handle_new_receipts(receipts)
+
+    @defer.inlineCallbacks
+    def _handle_new_receipts(self, receipts):
+        """Takes a list of receipts, stores them and informs the notifier.
+        """
+        for receipt in receipts:
+            room_id = receipt["room_id"]
+            receipt_type = receipt["receipt_type"]
+            user_id = receipt["user_id"]
+            event_ids = receipt["event_ids"]
+            data = receipt["data"]
+
+            res = yield self.store.insert_receipt(
+                room_id, receipt_type, user_id, event_ids, data
+            )
+
+            if not res:
+                # res will be None if this read receipt is 'old'
+                defer.returnValue(False)
+
+            stream_id, max_persisted_id = res
+
+            with PreserveLoggingContext():
+                self.notifier.on_new_event(
+                    "receipt_key", max_persisted_id, rooms=[room_id]
+                )
+
+            defer.returnValue(True)
+
+    @defer.inlineCallbacks
+    def _push_remotes(self, receipts):
+        """Given a list of receipts, works out which remote servers should be
+        poked and pokes them.
+        """
+        # TODO: Some of this stuff should be coallesced.
+        for receipt in receipts:
+            room_id = receipt["room_id"]
+            receipt_type = receipt["receipt_type"]
+            user_id = receipt["user_id"]
+            event_ids = receipt["event_ids"]
+            data = receipt["data"]
+
+            remotedomains = set()
+
+            rm_handler = self.hs.get_handlers().room_member_handler
+            yield rm_handler.fetch_room_distributions_into(
+                room_id, localusers=None, remotedomains=remotedomains
+            )
+
+            logger.debug("Sending receipt to: %r", remotedomains)
+
+            for domain in remotedomains:
+                self.federation.send_edu(
+                    destination=domain,
+                    edu_type="m.receipt",
+                    content={
+                        room_id: {
+                            receipt_type: {
+                                user_id: {
+                                    "event_ids": event_ids,
+                                    "data": data,
+                                }
+                            }
+                        },
+                    },
+                )
+
+    @defer.inlineCallbacks
+    def get_receipts_for_room(self, room_id, to_key):
+        """Gets all receipts for a room, upto the given key.
+        """
+        result = yield self.store.get_linearized_receipts_for_room(
+            room_id,
+            to_key=to_key,
+        )
+
+        if not result:
+            defer.returnValue([])
+
+        event = {
+            "type": "m.receipt",
+            "room_id": room_id,
+            "content": result,
+        }
+
+        defer.returnValue([event])
+
+
+class ReceiptEventSource(object):
+    def __init__(self, hs):
+        self.store = hs.get_datastore()
+
+    @defer.inlineCallbacks
+    def get_new_events_for_user(self, user, from_key, limit):
+        from_key = int(from_key)
+        to_key = yield self.get_current_key()
+
+        rooms = yield self.store.get_rooms_for_user(user.to_string())
+        rooms = [room.room_id for room in rooms]
+        events = yield self.store.get_linearized_receipts_for_rooms(
+            rooms,
+            from_key=from_key,
+            to_key=to_key,
+        )
+
+        defer.returnValue((events, to_key))
+
+    def get_current_key(self, direction='f'):
+        return self.store.get_max_receipt_stream_id()
+
+    @defer.inlineCallbacks
+    def get_pagination_rows(self, user, config, key):
+        to_key = int(config.from_key)
+
+        if config.to_key:
+            from_key = int(config.to_key)
+        else:
+            from_key = None
+
+        rooms = yield self.store.get_rooms_for_user(user.to_string())
+        rooms = [room.room_id for room in rooms]
+        events = yield self.store.get_linearized_receipts_for_rooms(
+            rooms,
+            from_key=from_key,
+            to_key=to_key,
+        )
+
+        defer.returnValue((events, to_key))
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py
index a9895292c2..026bd2b9d4 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -218,7 +218,7 @@ class TypingNotificationHandler(BaseHandler):
         self._room_serials[room_id] = self._latest_room_serial
 
         with PreserveLoggingContext():
-            self.notifier.on_new_user_event(
+            self.notifier.on_new_event(
                 "typing_key", self._latest_room_serial, rooms=[room_id]
             )
 
diff --git a/synapse/notifier.py b/synapse/notifier.py
index bdd03dcbe8..85ae343135 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -221,16 +221,7 @@ class Notifier(object):
             event
         )
 
-        room_id = event.room_id
-
-        room_user_streams = self.room_to_user_streams.get(room_id, set())
-
-        user_streams = room_user_streams.copy()
-
-        for user in extra_users:
-            user_stream = self.user_to_user_stream.get(str(user))
-            if user_stream is not None:
-                user_streams.add(user_stream)
+        app_streams = set()
 
         for appservice in self.appservice_to_user_streams:
             # TODO (kegan): Redundant appservice listener checks?
@@ -242,24 +233,20 @@ class Notifier(object):
                 app_user_streams = self.appservice_to_user_streams.get(
                     appservice, set()
                 )
-                user_streams |= app_user_streams
-
-        logger.debug("on_new_room_event listeners %s", user_streams)
+                app_streams |= app_user_streams
 
-        time_now_ms = self.clock.time_msec()
-        for user_stream in user_streams:
-            try:
-                user_stream.notify(
-                    "room_key", "s%d" % (room_stream_id,), time_now_ms
-                )
-            except:
-                logger.exception("Failed to notify listener")
+        self.on_new_event(
+            "room_key", room_stream_id,
+            users=extra_users,
+            rooms=[event.room_id],
+            extra_streams=app_streams,
+        )
 
     @defer.inlineCallbacks
     @log_function
-    def on_new_user_event(self, stream_key, new_token, users=[], rooms=[]):
-        """ Used to inform listeners that something has happend
-        presence/user event wise.
+    def on_new_event(self, stream_key, new_token, users=[], rooms=[],
+                     extra_streams=set()):
+        """ Used to inform listeners that something has happend event wise.
 
         Will wake up all listeners for the given users and rooms.
         """
@@ -283,7 +270,7 @@ class Notifier(object):
 
     @defer.inlineCallbacks
     def wait_for_events(self, user, rooms, timeout, callback,
-                        from_token=StreamToken("s0", "0", "0")):
+                        from_token=StreamToken("s0", "0", "0", "0")):
         """Wait until the callback returns a non empty response or the
         timeout fires.
         """
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 17587170c8..115bee8c41 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -31,6 +31,7 @@ REQUIREMENTS = {
     "pillow": ["PIL"],
     "pydenticon": ["pydenticon"],
     "ujson": ["ujson"],
+    "blist": ["blist"],
     "pysaml2": ["saml2"],
 }
 CONDITIONAL_REQUIREMENTS = {
diff --git a/synapse/rest/client/v2_alpha/__init__.py b/synapse/rest/client/v2_alpha/__init__.py
index c3323d2a8a..33f961e898 100644
--- a/synapse/rest/client/v2_alpha/__init__.py
+++ b/synapse/rest/client/v2_alpha/__init__.py
@@ -19,6 +19,7 @@ from . import (
     account,
     register,
     auth,
+    receipts,
     keys,
 )
 
@@ -39,4 +40,5 @@ class ClientV2AlphaRestResource(JsonResource):
         account.register_servlets(hs, client_resource)
         register.register_servlets(hs, client_resource)
         auth.register_servlets(hs, client_resource)
+        receipts.register_servlets(hs, client_resource)
         keys.register_servlets(hs, client_resource)
diff --git a/synapse/rest/client/v2_alpha/receipts.py b/synapse/rest/client/v2_alpha/receipts.py
new file mode 100644
index 0000000000..40406e2ede
--- /dev/null
+++ b/synapse/rest/client/v2_alpha/receipts.py
@@ -0,0 +1,55 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 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
+
+from synapse.http.servlet import RestServlet
+from ._base import client_v2_pattern
+
+import logging
+
+
+logger = logging.getLogger(__name__)
+
+
+class ReceiptRestServlet(RestServlet):
+    PATTERN = client_v2_pattern(
+        "/rooms/(?P<room_id>[^/]*)"
+        "/receipt/(?P<receipt_type>[^/]*)"
+        "/(?P<event_id>[^/]*)$"
+    )
+
+    def __init__(self, hs):
+        super(ReceiptRestServlet, self).__init__()
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.receipts_handler = hs.get_handlers().receipts_handler
+
+    @defer.inlineCallbacks
+    def on_POST(self, request, room_id, receipt_type, event_id):
+        user, client = yield self.auth.get_user_by_req(request)
+
+        yield self.receipts_handler.received_client_receipt(
+            room_id,
+            receipt_type,
+            user_id=user.to_string(),
+            event_id=event_id
+        )
+
+        defer.returnValue((200, {}))
+
+
+def register_servlets(hs, http_server):
+    ReceiptRestServlet(hs).register(http_server)
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index e089d81675..71d5d92500 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -39,6 +39,8 @@ from .signatures import SignatureStore
 from .filtering import FilteringStore
 from .end_to_end_keys import EndToEndKeyStore
 
+from .receipts import ReceiptsStore
+
 
 import fnmatch
 import imp
@@ -75,6 +77,7 @@ class DataStore(RoomMemberStore, RoomStore,
                 PushRuleStore,
                 ApplicationServiceTransactionStore,
                 EventsStore,
+                ReceiptsStore,
                 EndToEndKeyStore,
                 ):
 
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 8d33def6c6..8f812f0fd7 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -329,13 +329,14 @@ class SQLBaseStore(object):
 
         self.database_engine = hs.database_engine
 
-        self._stream_id_gen = StreamIdGenerator()
+        self._stream_id_gen = StreamIdGenerator("events", "stream_ordering")
         self._transaction_id_gen = IdGenerator("sent_transactions", "id", self)
         self._state_groups_id_gen = IdGenerator("state_groups", "id", self)
         self._access_tokens_id_gen = IdGenerator("access_tokens", "id", self)
         self._pushers_id_gen = IdGenerator("pushers", "id", self)
         self._push_rule_id_gen = IdGenerator("push_rules", "id", self)
         self._push_rules_enable_id_gen = IdGenerator("push_rules_enable", "id", self)
+        self._receipts_id_gen = StreamIdGenerator("receipts_linearized", "stream_id")
 
     def start_profiling(self):
         self._previous_loop_ts = self._clock.time_msec()
diff --git a/synapse/storage/receipts.py b/synapse/storage/receipts.py
new file mode 100644
index 0000000000..d515a0a15c
--- /dev/null
+++ b/synapse/storage/receipts.py
@@ -0,0 +1,348 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014, 2015 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from ._base import SQLBaseStore, cached
+
+from twisted.internet import defer
+
+from synapse.util import unwrapFirstError
+
+from blist import sorteddict
+import logging
+import ujson as json
+
+
+logger = logging.getLogger(__name__)
+
+
+class ReceiptsStore(SQLBaseStore):
+    def __init__(self, hs):
+        super(ReceiptsStore, self).__init__(hs)
+
+        self._receipts_stream_cache = _RoomStreamChangeCache()
+
+    @defer.inlineCallbacks
+    def get_linearized_receipts_for_rooms(self, room_ids, to_key, from_key=None):
+        """Get receipts for multiple rooms for sending to clients.
+
+        Args:
+            room_ids (list): List of room_ids.
+            to_key (int): Max stream id to fetch receipts upto.
+            from_key (int): Min stream id to fetch receipts from. None fetches
+                from the start.
+
+        Returns:
+            list: A list of receipts.
+        """
+        room_ids = set(room_ids)
+
+        if from_key:
+            room_ids = yield self._receipts_stream_cache.get_rooms_changed(
+                self, room_ids, from_key
+            )
+
+        results = yield defer.gatherResults(
+            [
+                self.get_linearized_receipts_for_room(
+                    room_id, to_key, from_key=from_key
+                )
+                for room_id in room_ids
+            ],
+            consumeErrors=True,
+        ).addErrback(unwrapFirstError)
+
+        defer.returnValue([ev for res in results for ev in res])
+
+    @defer.inlineCallbacks
+    def get_linearized_receipts_for_room(self, room_id, to_key, from_key=None):
+        """Get receipts for a single room for sending to clients.
+
+        Args:
+            room_ids (str): The room id.
+            to_key (int): Max stream id to fetch receipts upto.
+            from_key (int): Min stream id to fetch receipts from. None fetches
+                from the start.
+
+        Returns:
+            list: A list of receipts.
+        """
+        def f(txn):
+            if from_key:
+                sql = (
+                    "SELECT * FROM receipts_linearized WHERE"
+                    " room_id = ? AND stream_id > ? AND stream_id <= ?"
+                )
+
+                txn.execute(
+                    sql,
+                    (room_id, from_key, to_key)
+                )
+            else:
+                sql = (
+                    "SELECT * FROM receipts_linearized WHERE"
+                    " room_id = ? AND stream_id <= ?"
+                )
+
+                txn.execute(
+                    sql,
+                    (room_id, to_key)
+                )
+
+            rows = self.cursor_to_dict(txn)
+
+            return rows
+
+        rows = yield self.runInteraction(
+            "get_linearized_receipts_for_room", f
+        )
+
+        if not rows:
+            defer.returnValue([])
+
+        content = {}
+        for row in rows:
+            content.setdefault(
+                row["event_id"], {}
+            ).setdefault(
+                row["receipt_type"], {}
+            )[row["user_id"]] = json.loads(row["data"])
+
+        defer.returnValue([{
+            "type": "m.receipt",
+            "room_id": room_id,
+            "content": content,
+        }])
+
+    def get_max_receipt_stream_id(self):
+        return self._receipts_id_gen.get_max_token(self)
+
+    @cached
+    @defer.inlineCallbacks
+    def get_graph_receipts_for_room(self, room_id):
+        """Get receipts for sending to remote servers.
+        """
+        rows = yield self._simple_select_list(
+            table="receipts_graph",
+            keyvalues={"room_id": room_id},
+            retcols=["receipt_type", "user_id", "event_id"],
+            desc="get_linearized_receipts_for_room",
+        )
+
+        result = {}
+        for row in rows:
+            result.setdefault(
+                row["user_id"], {}
+            ).setdefault(
+                row["receipt_type"], []
+            ).append(row["event_id"])
+
+        defer.returnValue(result)
+
+    def insert_linearized_receipt_txn(self, txn, room_id, receipt_type,
+                                      user_id, event_id, data, stream_id):
+
+        # We don't want to clobber receipts for more recent events, so we
+        # have to compare orderings of existing receipts
+        sql = (
+            "SELECT topological_ordering, stream_ordering, event_id FROM events"
+            " INNER JOIN receipts_linearized as r USING (event_id, room_id)"
+            " WHERE r.room_id = ? AND r.receipt_type = ? AND r.user_id = ?"
+        )
+
+        txn.execute(sql, (room_id, receipt_type, user_id))
+        results = txn.fetchall()
+
+        if results:
+            res = self._simple_select_one_txn(
+                txn,
+                table="events",
+                retcols=["topological_ordering", "stream_ordering"],
+                keyvalues={"event_id": event_id},
+            )
+            topological_ordering = int(res["topological_ordering"])
+            stream_ordering = int(res["stream_ordering"])
+
+            for to, so, _ in results:
+                if int(to) > topological_ordering:
+                    return False
+                elif int(to) == topological_ordering and int(so) >= stream_ordering:
+                    return False
+
+        self._simple_delete_txn(
+            txn,
+            table="receipts_linearized",
+            keyvalues={
+                "room_id": room_id,
+                "receipt_type": receipt_type,
+                "user_id": user_id,
+            }
+        )
+
+        self._simple_insert_txn(
+            txn,
+            table="receipts_linearized",
+            values={
+                "stream_id": stream_id,
+                "room_id": room_id,
+                "receipt_type": receipt_type,
+                "user_id": user_id,
+                "event_id": event_id,
+                "data": json.dumps(data),
+            }
+        )
+
+        return True
+
+    @defer.inlineCallbacks
+    def insert_receipt(self, room_id, receipt_type, user_id, event_ids, data):
+        """Insert a receipt, either from local client or remote server.
+
+        Automatically does conversion between linearized and graph
+        representations.
+        """
+        if not event_ids:
+            return
+
+        if len(event_ids) == 1:
+            linearized_event_id = event_ids[0]
+        else:
+            # we need to points in graph -> linearized form.
+            # TODO: Make this better.
+            def graph_to_linear(txn):
+                query = (
+                    "SELECT event_id WHERE room_id = ? AND stream_ordering IN ("
+                    " SELECT max(stream_ordering) WHERE event_id IN (%s)"
+                    ")"
+                ) % (",".join(["?"] * len(event_ids)))
+
+                txn.execute(query, [room_id] + event_ids)
+                rows = txn.fetchall()
+                if rows:
+                    return rows[0][0]
+                else:
+                    raise RuntimeError("Unrecognized event_ids: %r" % (event_ids,))
+
+            linearized_event_id = yield self.runInteraction(
+                "insert_receipt_conv", graph_to_linear
+            )
+
+        stream_id_manager = yield self._receipts_id_gen.get_next(self)
+        with stream_id_manager as stream_id:
+            yield self._receipts_stream_cache.room_has_changed(
+                self, room_id, stream_id
+            )
+            have_persisted = yield self.runInteraction(
+                "insert_linearized_receipt",
+                self.insert_linearized_receipt_txn,
+                room_id, receipt_type, user_id, linearized_event_id,
+                data,
+                stream_id=stream_id,
+            )
+
+            if not have_persisted:
+                defer.returnValue(None)
+
+        yield self.insert_graph_receipt(
+            room_id, receipt_type, user_id, event_ids, data
+        )
+
+        max_persisted_id = yield self._stream_id_gen.get_max_token(self)
+        defer.returnValue((stream_id, max_persisted_id))
+
+    def insert_graph_receipt(self, room_id, receipt_type, user_id, event_ids,
+                             data):
+        return self.runInteraction(
+            "insert_graph_receipt",
+            self.insert_graph_receipt_txn,
+            room_id, receipt_type, user_id, event_ids, data
+        )
+
+    def insert_graph_receipt_txn(self, txn, room_id, receipt_type,
+                                 user_id, event_ids, data):
+        self._simple_delete_txn(
+            txn,
+            table="receipts_graph",
+            keyvalues={
+                "room_id": room_id,
+                "receipt_type": receipt_type,
+                "user_id": user_id,
+            }
+        )
+        self._simple_insert_txn(
+            txn,
+            table="receipts_graph",
+            values={
+                "room_id": room_id,
+                "receipt_type": receipt_type,
+                "user_id": user_id,
+                "event_ids": json.dumps(event_ids),
+                "data": json.dumps(data),
+            }
+        )
+
+
+class _RoomStreamChangeCache(object):
+    """Keeps track of the stream_id of the latest change in rooms.
+
+    Given a list of rooms and stream key, it will give a subset of rooms that
+    may have changed since that key. If the key is too old then the cache
+    will simply return all rooms.
+    """
+    def __init__(self, size_of_cache=1000):
+        self._size_of_cache = size_of_cache
+        self._room_to_key = {}
+        self._cache = sorteddict()
+        self._earliest_key = None
+
+    @defer.inlineCallbacks
+    def get_rooms_changed(self, store, room_ids, key):
+        """Returns subset of room ids that have had new receipts since the
+        given key. If the key is too old it will just return the given list.
+        """
+        if key > (yield self._get_earliest_key(store)):
+            keys = self._cache.keys()
+            i = keys.bisect_right(key)
+
+            result = set(
+                self._cache[k] for k in keys[i:]
+            ).intersection(room_ids)
+        else:
+            result = room_ids
+
+        defer.returnValue(result)
+
+    @defer.inlineCallbacks
+    def room_has_changed(self, store, room_id, key):
+        """Informs the cache that the room has been changed at the given key.
+        """
+        if key > (yield self._get_earliest_key(store)):
+            old_key = self._room_to_key.get(room_id, None)
+            if old_key:
+                key = max(key, old_key)
+                self._cache.pop(old_key, None)
+            self._cache[key] = room_id
+
+            while len(self._cache) > self._size_of_cache:
+                k, r = self._cache.popitem()
+                self._earliest_key = max(k, self._earliest_key)
+                self._room_to_key.pop(r, None)
+
+    @defer.inlineCallbacks
+    def _get_earliest_key(self, store):
+        if self._earliest_key is None:
+            self._earliest_key = yield store.get_max_receipt_stream_id()
+            self._earliest_key = int(self._earliest_key)
+
+        defer.returnValue(self._earliest_key)
diff --git a/synapse/storage/schema/delta/21/receipts.sql b/synapse/storage/schema/delta/21/receipts.sql
new file mode 100644
index 0000000000..2f64d609fc
--- /dev/null
+++ b/synapse/storage/schema/delta/21/receipts.sql
@@ -0,0 +1,38 @@
+/* Copyright 2015 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+CREATE TABLE IF NOT EXISTS receipts_graph(
+    room_id TEXT NOT NULL,
+    receipt_type TEXT NOT NULL,
+    user_id TEXT NOT NULL,
+    event_ids TEXT NOT NULL,
+    data TEXT NOT NULL,
+    CONSTRAINT receipts_graph_uniqueness UNIQUE (room_id, receipt_type, user_id)
+);
+
+CREATE TABLE IF NOT EXISTS receipts_linearized (
+    stream_id BIGINT NOT NULL,
+    room_id TEXT NOT NULL,
+    receipt_type TEXT NOT NULL,
+    user_id TEXT NOT NULL,
+    event_id TEXT NOT NULL,
+    data TEXT NOT NULL,
+    CONSTRAINT receipts_linearized_uniqueness UNIQUE (room_id, receipt_type, user_id)
+);
+
+CREATE INDEX receipts_linearized_id ON receipts_linearized(
+  stream_id
+);
diff --git a/synapse/storage/util/id_generators.py b/synapse/storage/util/id_generators.py
index 83eab63098..e956df62c7 100644
--- a/synapse/storage/util/id_generators.py
+++ b/synapse/storage/util/id_generators.py
@@ -72,7 +72,10 @@ class StreamIdGenerator(object):
         with stream_id_gen.get_next_txn(txn) as stream_id:
             # ... persist event ...
     """
-    def __init__(self):
+    def __init__(self, table, column):
+        self.table = table
+        self.column = column
+
         self._lock = threading.Lock()
 
         self._current_max = None
@@ -157,7 +160,7 @@ class StreamIdGenerator(object):
 
     def _get_or_compute_current_max(self, txn):
         with self._lock:
-            txn.execute("SELECT MAX(stream_ordering) FROM events")
+            txn.execute("SELECT MAX(%s) FROM %s" % (self.column, self.table))
             rows = txn.fetchall()
             val, = rows[0]
 
diff --git a/synapse/streams/events.py b/synapse/streams/events.py
index dff7970bea..aaa3609aa5 100644
--- a/synapse/streams/events.py
+++ b/synapse/streams/events.py
@@ -20,6 +20,7 @@ from synapse.types import StreamToken
 from synapse.handlers.presence import PresenceEventSource
 from synapse.handlers.room import RoomEventSource
 from synapse.handlers.typing import TypingNotificationEventSource
+from synapse.handlers.receipts import ReceiptEventSource
 
 
 class NullSource(object):
@@ -43,6 +44,7 @@ class EventSources(object):
         "room": RoomEventSource,
         "presence": PresenceEventSource,
         "typing": TypingNotificationEventSource,
+        "receipt": ReceiptEventSource,
     }
 
     def __init__(self, hs):
@@ -62,7 +64,10 @@ class EventSources(object):
             ),
             typing_key=(
                 yield self.sources["typing"].get_current_key()
-            )
+            ),
+            receipt_key=(
+                yield self.sources["receipt"].get_current_key()
+            ),
         )
         defer.returnValue(token)
 
diff --git a/synapse/types.py b/synapse/types.py
index 1b21160c57..dd1b10d646 100644
--- a/synapse/types.py
+++ b/synapse/types.py
@@ -100,7 +100,7 @@ class EventID(DomainSpecificString):
 class StreamToken(
     namedtuple(
         "Token",
-        ("room_key", "presence_key", "typing_key")
+        ("room_key", "presence_key", "typing_key", "receipt_key")
     )
 ):
     _SEPARATOR = "_"
@@ -109,6 +109,9 @@ class StreamToken(
     def from_string(cls, string):
         try:
             keys = string.split(cls._SEPARATOR)
+            if len(keys) == len(cls._fields) - 1:
+                # i.e. old token from before receipt_key
+                keys.append("0")
             return cls(*keys)
         except:
             raise SynapseError(400, "Invalid Token")
@@ -131,6 +134,7 @@ class StreamToken(
             (other_token.room_stream_id < self.room_stream_id)
             or (int(other_token.presence_key) < int(self.presence_key))
             or (int(other_token.typing_key) < int(self.typing_key))
+            or (int(other_token.receipt_key) < int(self.receipt_key))
         )
 
     def copy_and_advance(self, key, new_value):