Add helper function for getting access_tokens from requests

Rather than reimplementing the token parsing in the various places.
This will make it easier to change the token parsing to allow access_tokens
in HTTP headers.

synapse/api/auth.py

@@ -583,12 +583,15 @@ def get_user_by_req(self, request, allow_guest=False, rights="access"):
         """
         # Can optionally look elsewhere in the request (e.g. headers)
         try:
-            user_id = yield self._get_appservice_user_id(request.args)
+            user_id = yield self._get_appservice_user_id(request)
             if user_id:
                 request.authenticated_entity = user_id
                 defer.returnValue(synapse.types.create_requester(user_id))
 
-            access_token = request.args["access_token"][0]
+            access_token = get_access_token_from_request(
+                request, self.TOKEN_NOT_FOUND_HTTP_STATUS
+            )
+
             user_info = yield self.get_user_by_access_token(access_token, rights)
             user = user_info["user"]
             token_id = user_info["token_id"]
@@ -629,17 +632,19 @@ def get_user_by_req(self, request, allow_guest=False, rights="access"):
             )
 
     @defer.inlineCallbacks
-    def _get_appservice_user_id(self, request_args):
+    def _get_appservice_user_id(self, request):
         app_service = yield self.store.get_app_service_by_token(
-            request_args["access_token"][0]
+            get_access_token_from_request(
+                request, self.TOKEN_NOT_FOUND_HTTP_STATUS
+            )
         )
         if app_service is None:
             defer.returnValue(None)
 
-        if "user_id" not in request_args:
+        if "user_id" not in request.args:
             defer.returnValue(app_service.sender)
 
-        user_id = request_args["user_id"][0]
+        user_id = request.args["user_id"][0]
         if app_service.sender == user_id:
             defer.returnValue(app_service.sender)
 
@@ -833,7 +838,9 @@ def _look_up_user_by_access_token(self, token):
     @defer.inlineCallbacks
     def get_appservice_by_req(self, request):
         try:
-            token = request.args["access_token"][0]
+            token = get_access_token_from_request(
+                request, self.TOKEN_NOT_FOUND_HTTP_STATUS
+            )
             service = yield self.store.get_app_service_by_token(token)
             if not service:
                 logger.warn("Unrecognised appservice access token: %s" % (token,))
@@ -1142,3 +1149,40 @@ def check_can_change_room_list(self, room_id, user):
                 "This server requires you to be a moderator in the room to"
                 " edit its room list entry"
             )
+
+
+def has_access_token(request):
+    """Checks if the request has an access_token.
+
+    Returns:
+        bool: False if no access_token was given, True otherwise.
+    """
+    query_params = request.args.get("access_token")
+    return bool(query_params)
+
+
+def get_access_token_from_request(request, token_not_found_http_status=401):
+    """Extracts the access_token from the request.
+
+    Args:
+        request: The http request.
+        token_not_found_http_status(int): The HTTP status code to set in the
+            AuthError if the token isn't found. This is used in some of the
+            legacy APIs to change the status code to 403 from the default of
+            401 since some of the old clients depended on auth errors returning
+            403.
+    Returns:
+        str: The access_token
+    Raises:
+        AuthError: If there isn't an access_token in the request.
+    """
+    query_params = request.args.get("access_token")
+    # Try to get the access_token from the query params.
+    if not query_params:
+        raise AuthError(
+            token_not_found_http_status,
+            "Missing access token.",
+            errcode=Codes.MISSING_TOKEN
+        )
+
+    return query_params[0]

synapse/rest/client/v1/logout.py

@@ -15,7 +15,7 @@
 
 from twisted.internet import defer
 
-from synapse.api.errors import AuthError, Codes
+from synapse.api.auth import get_access_token_from_request
 
 from .base import ClientV1RestServlet, client_path_patterns
 
@@ -37,13 +37,7 @@ def on_OPTIONS(self, request):
 
     @defer.inlineCallbacks
     def on_POST(self, request):
-        try:
-            access_token = request.args["access_token"][0]
-        except KeyError:
-            raise AuthError(
-                self.TOKEN_NOT_FOUND_HTTP_STATUS, "Missing access token.",
-                errcode=Codes.MISSING_TOKEN
-            )
+        access_token = get_access_token_from_request(request)
         yield self.store.delete_access_token(access_token)
         defer.returnValue((200, {}))
 

synapse/rest/client/v1/register.py

@@ -18,6 +18,7 @@
 
 from synapse.api.errors import SynapseError, Codes
 from synapse.api.constants import LoginType
+from synapse.api.auth import get_access_token_from_request
 from .base import ClientV1RestServlet, client_path_patterns
 import synapse.util.stringutils as stringutils
 from synapse.http.servlet import parse_json_object_from_request
@@ -296,12 +297,11 @@ def _do_password(self, request, register_json, session):
 
     @defer.inlineCallbacks
     def _do_app_service(self, request, register_json, session):
-        if "access_token" not in request.args:
-            raise SynapseError(400, "Expected application service token.")
+        as_token = get_access_token_from_request(request)
+
         if "user" not in register_json:
             raise SynapseError(400, "Expected 'user' key.")
 
-        as_token = request.args["access_token"][0]
         user_localpart = register_json["user"].encode("utf-8")
 
         handler = self.handlers.registration_handler
@@ -390,11 +390,9 @@ def __init__(self, hs):
     def on_POST(self, request):
         user_json = parse_json_object_from_request(request)
 
-        if "access_token" not in request.args:
-            raise SynapseError(400, "Expected application service token.")
-
+        access_token = get_access_token_from_request(request)
         app_service = yield self.store.get_app_service_by_token(
-            request.args["access_token"][0]
+            access_token
         )
         if not app_service:
             raise SynapseError(403, "Invalid application service token.")

synapse/rest/client/v1/transactions.py

@@ -17,6 +17,8 @@
 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__)
 
 
@@ -90,6 +92,6 @@ def get_client_transaction(self, request, txn_id):
         return response
 
     def _get_key(self, request):
-        token = request.args["access_token"][0]
+        token = get_access_token_from_request(request)
         path_without_txn_id = request.path.rsplit("/", 1)[0]
         return path_without_txn_id + "/" + token

synapse/rest/client/v2_alpha/register.py

@@ -15,6 +15,7 @@
 
 from twisted.internet import defer
 
+from synapse.api.auth import get_access_token_from_request, has_access_token
 from synapse.api.constants import LoginType
 from synapse.api.errors import SynapseError, Codes, UnrecognizedRequestError
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
@@ -131,7 +132,7 @@ def on_POST(self, request):
             desired_username = body['username']
 
         appservice = None
-        if 'access_token' in request.args:
+        if has_access_token(request):
             appservice = yield self.auth.get_appservice_by_req(request)
 
         # fork off as soon as possible for ASes and shared secret auth which
@@ -143,10 +144,11 @@ def on_POST(self, request):
             # 'user' key not 'username'). Since this is a new addition, we'll
             # fallback to 'username' if they gave one.
             desired_username = body.get("user", desired_username)
+            access_token = get_access_token_from_request(request)
 
             if isinstance(desired_username, basestring):
                 result = yield self._do_appservice_registration(
-                    desired_username, request.args["access_token"][0], body
+                    desired_username, access_token, body
                 )
             defer.returnValue((200, result))  # we throw for non 200 responses
             return

synapse/rest/client/v2_alpha/thirdparty.py

@@ -57,7 +57,7 @@ def on_GET(self, request, protocol):
         yield self.auth.get_user_by_req(request)
 
         fields = request.args
-        del fields["access_token"]
+        fields.pop("access_token", None)
 
         results = yield self.appservice_handler.query_3pe(
             ThirdPartyEntityKind.USER, protocol, fields
@@ -81,7 +81,7 @@ def on_GET(self, request, protocol):
         yield self.auth.get_user_by_req(request)
 
         fields = request.args
-        del fields["access_token"]
+        fields.pop("access_token", None)
 
         results = yield self.appservice_handler.query_3pe(
             ThirdPartyEntityKind.LOCATION, protocol, fields