3 files changed, 168 insertions, 0 deletions
diff --git a/synapse/rest/base.py b/synapse/rest/base.py
index 6a88cbe866..e855d293e5 100644
--- a/synapse/rest/base.py
+++ b/synapse/rest/base.py
@@ -15,6 +15,7 @@
 
 """ This module contains base REST classes for constructing REST servlets. """
 from synapse.api.urls import CLIENT_PREFIX
+from synapse.rest.transactions import HttpTransactionStore
 import re
 
 
@@ -59,6 +60,7 @@ class RestServlet(object):
         self.handlers = hs.get_handlers()
         self.event_factory = hs.get_event_factory()
         self.auth = hs.get_auth()
+        self.txns = HttpTransactionStore()
 
     def register(self, http_server):
         """ Register this servlet with the given HTTP server. """
diff --git a/synapse/rest/room.py b/synapse/rest/room.py
index 2d681bd893..731317227d 100644
--- a/synapse/rest/room.py
+++ b/synapse/rest/room.py
@@ -366,6 +366,51 @@ class RoomTriggerBackfill(RestServlet):
         defer.returnValue((200, res))
 
 
+class RoomMembershipRestServlet(RestServlet):
+
+    def register(self, http_server):
+        # /rooms/$roomid/[invite|join|leave]
+        PATTERN = ("/rooms/(?P<room_id>[^/]*)/" +
+            "(?P<membership_action>join|invite|leave)")
+        register_txn_path(self, PATTERN, http_server)
+
+    @defer.inlineCallbacks
+    def on_POST(self, request, room_id, membership_action):
+        user = yield self.auth.get_user_by_req(request)
+
+        content = _parse_json(request)
+
+        # target user is you unless it is an invite
+        state_key = user.to_string()
+        if membership_action == "invite":
+            if "user_id" not in content:
+                raise SynapseError(400, "Missing user_id key.")
+            state_key = content["user_id"]
+
+        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
+        )
+        handler = self.handlers.room_member_handler
+        yield handler.change_membership(event)
+        defer.returnValue((200, ""))
+
+    @defer.inlineCallbacks
+    def on_PUT(self, request, room_id, membership_action, txn_id):
+        try:
+            defer.returnValue(self.txns.get_client_transaction(request, txn_id))
+        except:
+            pass
+
+        response = yield self.on_POST(request, room_id, membership_action)
+
+        self.txns.store_client_transaction(request, txn_id, response)
+        defer.returnValue(response)
+
+
 def _parse_json(request):
     try:
         content = json.loads(request.content.read())
@@ -377,6 +422,30 @@ def _parse_json(request):
         raise SynapseError(400, "Content not JSON.", errcode=Codes.NOT_JSON)
 
 
+def register_txn_path(servlet, regex_string, http_server):
+    """Registers a transaction-based path.
+
+    This registers two paths:
+        PUT regex_string/$txnid
+        POST regex_string
+
+    Args:
+        regex_string (str): The regex string to register. Must NOT have a
+        trailing $ as this string will be appended to.
+        http_server : The http_server to register paths with.
+    """
+    http_server.register_path(
+        "POST",
+        client_path_pattern(regex_string + "$"),
+        servlet.on_POST
+    )
+    http_server.register_path(
+        "PUT",
+        client_path_pattern(regex_string + "/(?P<txn_id>[^/]*)$"),
+        servlet.on_PUT
+    )
+
+
 def register_servlets(hs, http_server):
     RoomStateEventRestServlet(hs).register(http_server)
     MessageRestServlet(hs).register(http_server)
@@ -386,3 +455,4 @@ def register_servlets(hs, http_server):
     RoomMessageListRestServlet(hs).register(http_server)
     JoinRoomAliasServlet(hs).register(http_server)
     RoomTriggerBackfill(hs).register(http_server)
+    RoomMembershipRestServlet(hs).register(http_server)
diff --git a/synapse/rest/transactions.py b/synapse/rest/transactions.py
new file mode 100644
index 0000000000..b8aa1ef11c
--- /dev/null
+++ b/synapse/rest/transactions.py
@@ -0,0 +1,96 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 matrix.org
+#
+# 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.
+
+"""This module contains logic for storing HTTP PUT transactions. This is used
+to ensure idempotency when performing PUTs using the REST API."""
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class HttpTransactionStore(object):
+
+    def __init__(self):
+        # { key : (txn_id, response) }
+        self.transactions = {}
+
+    def get_response(self, key, txn_id):
+        """Retrieve a response for this request.
+
+        Args:
+            key (str): A transaction-independent key for this request. Typically
+            this is a combination of the path (without the transaction id) and
+            the user's access token.
+            txn_id (str): The transaction ID for this request
+        Returns:
+            A tuple of (HTTP response code, response content) or None.
+        """
+        try:
+            logger.debug("get_response Key: %s TxnId: %s", key, txn_id)
+            (last_txn_id, response) = self.transactions[key]
+            if txn_id == last_txn_id:
+                logger.info("get_response: Returning a response for %s", key)
+                return response
+        except KeyError:
+            pass
+        return None
+
+    def store_response(self, key, txn_id, response):
+        """Stores an HTTP response tuple.
+
+        Args:
+            key (str): A transaction-independent key for this request. Typically
+            this is a combination of the path (without the transaction id) and
+            the user's access token.
+            txn_id (str): The transaction ID for this request.
+            response (tuple): A tuple of (HTTP response code, response content)
+        """
+        logger.debug("store_response Key: %s TxnId: %s", key, txn_id)
+        self.transactions[key] = (txn_id, response)
+
+    def store_client_transaction(self, request, txn_id, response):
+        """Stores the request/response pair of an HTTP transaction.
+
+        Args:
+            request (twisted.web.http.Request): The twisted HTTP request. This
+            request must have the transaction ID as the last path segment.
+            response (tuple): A tuple of (response code, response dict)
+            txn_id (str): The transaction ID for this request.
+        """
+        self.store_response(self._get_key(request), txn_id, response)
+
+    def get_client_transaction(self, request, txn_id):
+        """Retrieves a stored response if there was one.
+
+        Args:
+            request (twisted.web.http.Request): The twisted HTTP request. This
+            request must have the transaction ID as the last path segment.
+            txn_id (str): The transaction ID for this request.
+        Returns:
+            The response tuple.
+        Raises:
+            KeyError if the transaction was not found.
+        """
+        response = self.get_response(self._get_key(request), txn_id)
+        if response is None:
+            raise KeyError("Transaction not found.")
+        return response
+
+    def _get_key(self, request):
+        token = request.args["access_token"][0]
+        path_without_txn_id = request.path.rsplit("/", 1)[0]
+        return path_without_txn_id + "/" + token
+
+