Review comments

3 files changed, 29 insertions, 146 deletions

diff --git a/synapse/rest/client/v1/base.py b/synapse/rest/client/v1/base.py
index 22c740c30c..07ff5b218c 100644
--- a/synapse/rest/client/v1/base.py
+++ b/synapse/rest/client/v1/base.py
@@ -18,7 +18,8 @@
 
 from synapse.http.servlet import RestServlet
 from synapse.api.urls import CLIENT_PREFIX
-from .transactions import HttpTransactionCache
+from synapse.rest.client.transactions import HttpTransactionCache
+
 import re
 
 import logging
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 7af4077721..0622e64380 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -22,7 +22,6 @@ from synapse.streams.config import PaginationConfig
 from synapse.api.constants import EventTypes, Membership
 from synapse.api.filtering import Filter
 from synapse.types import UserID, RoomID, RoomAlias
-from synapse.util.async import ObservableDeferred
 from synapse.events.utils import serialize_event, format_event_for_client_v2
 from synapse.http.servlet import (
     parse_json_object_from_request, parse_string, parse_integer
@@ -56,17 +55,11 @@ class RoomCreateRestServlet(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_PUT(self, request, txn_id):
-        try:
-            res_deferred = self.txns.get_client_transaction(request, txn_id)
-            res = yield res_deferred.observe()
-            defer.returnValue(res)
-        except KeyError:
-            pass
-
-        res_deferred = ObservableDeferred(self.on_POST(request))
-        self.txns.store_client_transaction(request, txn_id, res_deferred)
-        response = yield res_deferred.observe()
-        defer.returnValue(response)
+        observable = self.txns.fetch_or_execute_request(
+            request, self.on_POST, request
+        )
+        res = yield observable.observe()
+        defer.returnValue(res)
 
     @defer.inlineCallbacks
     def on_POST(self, request):
@@ -217,19 +210,11 @@ class RoomSendEventRestServlet(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_PUT(self, request, room_id, event_type, txn_id):
-        try:
-            res_deferred = self.txns.get_client_transaction(request, txn_id)
-            res = yield res_deferred.observe()
-            defer.returnValue(res)
-        except KeyError:
-            pass
-
-        res_deferred = ObservableDeferred(
-            self.on_POST(request, room_id, event_type, txn_id)
+        observable = self.txns.fetch_or_execute_request(
+            request, self.on_POST, request, room_id, event_type, txn_id
         )
-        self.txns.store_client_transaction(request, txn_id, res_deferred)
-        response = yield res_deferred.observe()
-        defer.returnValue(response)
+        res = yield observable.observe()
+        defer.returnValue(res)
 
 
 # TODO: Needs unit testing for room ID + alias joins
@@ -288,17 +273,11 @@ class JoinRoomAliasServlet(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_PUT(self, request, room_identifier, txn_id):
-        try:
-            res_deferred = self.txns.get_client_transaction(request, txn_id)
-            res = yield res_deferred.observe()
-            defer.returnValue(res)
-        except KeyError:
-            pass
-
-        res_deferred = ObservableDeferred(self.on_POST(request, room_identifier, txn_id))
-        self.txns.store_client_transaction(request, txn_id, res_deferred)
-        response = yield res_deferred.observe()
-        defer.returnValue(response)
+        observable = self.txns.fetch_or_execute_request(
+            request, self.on_POST, request, room_identifier, txn_id
+        )
+        res = yield observable.observe()
+        defer.returnValue(res)
 
 
 # TODO: Needs unit testing
@@ -542,17 +521,11 @@ class RoomForgetRestServlet(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_PUT(self, request, room_id, txn_id):
-        try:
-            res_deferred = self.txns.get_client_transaction(request, txn_id)
-            res = yield res_deferred.observe()
-            defer.returnValue(res)
-        except KeyError:
-            pass
-
-        res_deferred = ObservableDeferred(self.on_POST(request, room_id, txn_id))
-        self.txns.store_client_transaction(request, txn_id, res_deferred)
-        response = yield res_deferred.observe()
-        defer.returnValue(response)
+        observable = self.txns.fetch_or_execute_request(
+            request, self.on_POST, request, room_id, txn_id
+        )
+        res = yield observable.observe()
+        defer.returnValue(res)
 
 
 # TODO: Needs unit testing
@@ -626,19 +599,11 @@ class RoomMembershipRestServlet(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_PUT(self, request, room_id, membership_action, txn_id):
-        try:
-            res_deferred = self.txns.get_client_transaction(request, txn_id)
-            res = yield res_deferred.observe()
-            defer.returnValue(res)
-        except KeyError:
-            pass
-
-        res_deferred = ObservableDeferred(
-            self.on_POST(request, room_id, membership_action, txn_id)
+        observable = self.txns.fetch_or_execute_request(
+            request, self.on_POST, request, room_id, membership_action, txn_id
         )
-        self.txns.store_client_transaction(request, txn_id, res_deferred)
-        response = yield res_deferred.observe()
-        defer.returnValue(response)
+        res = yield observable.observe()
+        defer.returnValue(res)
 
 
 class RoomRedactEventRestServlet(ClientV1RestServlet):
@@ -672,19 +637,11 @@ class RoomRedactEventRestServlet(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_PUT(self, request, room_id, event_id, txn_id):
-        try:
-            res_deferred = self.txns.get_client_transaction(request, txn_id)
-            res = yield res_deferred.observe()
-            defer.returnValue(res)
-        except KeyError:
-            pass
-
-        res_deferred = ObservableDeferred(
-            self.on_POST(request, room_id, event_id, txn_id)
+        observable = self.txns.fetch_or_execute_request(
+            request, self.on_POST, request, room_id, event_id, txn_id
         )
-        self.txns.store_client_transaction(request, txn_id, res_deferred)
-        response = yield res_deferred.observe()
-        defer.returnValue(response)
+        res = yield observable.observe()
+        defer.returnValue(res)
 
 
 class RoomTypingRestServlet(ClientV1RestServlet):
diff --git a/synapse/rest/client/v1/transactions.py b/synapse/rest/client/v1/transactions.py
deleted file mode 100644
index 774430458a..0000000000
--- a/synapse/rest/client/v1/transactions.py
+++ /dev/null
@@ -1,75 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2014-2016 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.
-
-"""This module contains logic for storing HTTP PUT transactions. This is used
-to ensure idempotency when performing PUTs using the REST API."""
-import logging
-
-from synapse.api.auth import get_access_token_from_request
-
-logger = logging.getLogger(__name__)
-
-
-class HttpTransactionCache(object):
-
-    def __init__(self):
-        # { key : (txn_id, res_observ_defer) }
-        self.transactions = {}
-
-    def _get_response(self, key, txn_id):
-        try:
-            (last_txn_id, res_observ_defer) = self.transactions[key]
-            if txn_id == last_txn_id:
-                logger.info("get_response: Returning a response for %s", txn_id)
-                return res_observ_defer
-        except KeyError:
-            pass
-        return None
-
-    def _store_response(self, key, txn_id, res_observ_defer):
-        self.transactions[key] = (txn_id, res_observ_defer)
-
-    def store_client_transaction(self, request, txn_id, res_observ_defer):
-        """Stores the request/Promise<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.
-            res_observ_defer (Promise<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, res_observ_defer)
-
-    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:
-            Promise: Resolves to the response tuple.
-        Raises:
-            KeyError if the transaction was not found.
-        """
-        res_observ_defer = self._get_response(self._get_key(request), txn_id)
-        if res_observ_defer is None:
-            raise KeyError("Transaction not found.")
-        return res_observ_defer
-
-    def _get_key(self, request):
-        token = get_access_token_from_request(request)
-        path_without_txn_id = request.path.rsplit("/", 1)[0]
-        return path_without_txn_id + "/" + token