Factor out an "assert_requester_is_admin" function (#5120)

Rather than copying-and-pasting the same four lines hundreds of times

4 files changed, 81 insertions, 76 deletions

diff --git a/changelog.d/5120.misc b/changelog.d/5120.misc
new file mode 100644
index 0000000000..6575f29322
--- /dev/null
+++ b/changelog.d/5120.misc
@@ -0,0 +1 @@
+Factor out an "assert_requester_is_admin" function.
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 960e66dbdc..0c6c93a87b 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -556,7 +556,7 @@ class Auth(object):
         """ Check if the given user is a local server admin.
 
         Args:
-            user (str): mxid of user to check
+            user (UserID): user to check
 
         Returns:
             bool: True if the user is an admin
diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index afac8b1724..d02f5198b8 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -36,6 +36,7 @@ from synapse.http.servlet import (
     parse_json_object_from_request,
     parse_string,
 )
+from synapse.rest.admin._base import assert_requester_is_admin, assert_user_is_admin
 from synapse.types import UserID, create_requester
 from synapse.util.versionstring import get_version_string
 
@@ -75,15 +76,7 @@ class UsersRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_GET(self, request, user_id):
         target_user = UserID.from_string(user_id)
-        requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
-
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
-
-        # To allow all users to get the users list
-        # if not is_admin and target_user != auth_user:
-        #     raise AuthError(403, "You are not a server admin")
+        yield assert_requester_is_admin(self.auth, request)
 
         if not self.hs.is_mine(target_user):
             raise SynapseError(400, "Can only users a local user")
@@ -101,11 +94,7 @@ class VersionServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
-
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
+        yield assert_requester_is_admin(self.auth, request)
 
         ret = {
             'server_version': get_version_string(synapse),
@@ -265,10 +254,9 @@ class WhoisRestServlet(RestServlet):
         target_user = UserID.from_string(user_id)
         requester = yield self.auth.get_user_by_req(request)
         auth_user = requester.user
-        is_admin = yield self.auth.is_server_admin(requester.user)
 
-        if not is_admin and target_user != auth_user:
-            raise AuthError(403, "You are not a server admin")
+        if target_user != auth_user:
+            yield assert_user_is_admin(self.auth, auth_user)
 
         if not self.hs.is_mine(target_user):
             raise SynapseError(400, "Can only whois a local user")
@@ -287,11 +275,7 @@ class PurgeMediaCacheRestServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_POST(self, request):
-        requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
-
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
+        yield assert_requester_is_admin(self.auth, request)
 
         before_ts = parse_integer(request, "before_ts", required=True)
         logger.info("before_ts: %r", before_ts)
@@ -318,11 +302,7 @@ class PurgeHistoryRestServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_POST(self, request, room_id, event_id):
-        requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
-
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
+        yield assert_requester_is_admin(self.auth, request)
 
         body = parse_json_object_from_request(request, allow_empty_body=True)
 
@@ -414,11 +394,7 @@ class PurgeHistoryStatusRestServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, purge_id):
-        requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
-
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
+        yield assert_requester_is_admin(self.auth, request)
 
         purge_status = self.pagination_handler.get_purge_status(purge_id)
         if purge_status is None:
@@ -436,6 +412,7 @@ class DeactivateAccountRestServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_POST(self, request, target_user_id):
+        yield assert_requester_is_admin(self.auth, request)
         body = parse_json_object_from_request(request, allow_empty_body=True)
         erase = body.get("erase", False)
         if not isinstance(erase, bool):
@@ -446,11 +423,6 @@ class DeactivateAccountRestServlet(RestServlet):
             )
 
         UserID.from_string(target_user_id)
-        requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
-
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
 
         result = yield self._deactivate_account_handler.deactivate_account(
             target_user_id, erase,
@@ -490,9 +462,7 @@ class ShutdownRoomRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_POST(self, request, room_id):
         requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
+        yield assert_user_is_admin(self.auth, requester.user)
 
         content = parse_json_object_from_request(request)
         assert_params_in_dict(content, ["new_room_user_id"])
@@ -605,9 +575,7 @@ class QuarantineMediaInRoom(RestServlet):
     @defer.inlineCallbacks
     def on_POST(self, request, room_id):
         requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
+        yield assert_user_is_admin(self.auth, requester.user)
 
         num_quarantined = yield self.store.quarantine_media_ids_in_room(
             room_id, requester.user.to_string(),
@@ -662,12 +630,10 @@ class ResetPasswordRestServlet(RestServlet):
         """Post request to allow an administrator reset password for a user.
         This needs user to have administrator access in Synapse.
         """
-        UserID.from_string(target_user_id)
         requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
+        yield assert_user_is_admin(self.auth, requester.user)
 
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
+        UserID.from_string(target_user_id)
 
         params = parse_json_object_from_request(request)
         assert_params_in_dict(params, ["new_password"])
@@ -701,16 +667,9 @@ class GetUsersPaginatedRestServlet(RestServlet):
         """Get request to get specific number of users from Synapse.
         This needs user to have administrator access in Synapse.
         """
-        target_user = UserID.from_string(target_user_id)
-        requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
+        yield assert_requester_is_admin(self.auth, request)
 
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
-
-        # To allow all users to get the users list
-        # if not is_admin and target_user != auth_user:
-        #     raise AuthError(403, "You are not a server admin")
+        target_user = UserID.from_string(target_user_id)
 
         if not self.hs.is_mine(target_user):
             raise SynapseError(400, "Can only users a local user")
@@ -741,12 +700,8 @@ class GetUsersPaginatedRestServlet(RestServlet):
         Returns:
             200 OK with json object {list[dict[str, Any]], count} or empty object.
         """
+        yield assert_requester_is_admin(self.auth, request)
         UserID.from_string(target_user_id)
-        requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
-
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
 
         order = "name"  # order by name in user table
         params = parse_json_object_from_request(request)
@@ -785,12 +740,9 @@ class SearchUsersRestServlet(RestServlet):
         search term.
         This needs user to have a administrator access in Synapse.
         """
-        target_user = UserID.from_string(target_user_id)
-        requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
+        yield assert_requester_is_admin(self.auth, request)
 
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
+        target_user = UserID.from_string(target_user_id)
 
         # To allow all users to get the users list
         # if not is_admin and target_user != auth_user:
@@ -821,10 +773,7 @@ class DeleteGroupAdminRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_POST(self, request, group_id):
         requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
-
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
+        yield assert_user_is_admin(self.auth, requester.user)
 
         if not self.is_mine_id(group_id):
             raise SynapseError(400, "Can only delete local groups")
@@ -847,11 +796,7 @@ class AccountValidityRenewServlet(RestServlet):
 
     @defer.inlineCallbacks
     def on_POST(self, request):
-        requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
-
-        if not is_admin:
-            raise AuthError(403, "You are not a server admin")
+        yield assert_requester_is_admin(self.auth, request)
 
         body = parse_json_object_from_request(request)
 
diff --git a/synapse/rest/admin/_base.py b/synapse/rest/admin/_base.py
new file mode 100644
index 0000000000..881d67b89c
--- /dev/null
+++ b/synapse/rest/admin/_base.py
@@ -0,0 +1,59 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 New Vector 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.api.errors import AuthError
+
+
+@defer.inlineCallbacks
+def assert_requester_is_admin(auth, request):
+    """Verify that the requester is an admin user
+
+    WARNING: MAKE SURE YOU YIELD ON THE RESULT!
+
+    Args:
+        auth (synapse.api.auth.Auth):
+        request (twisted.web.server.Request): incoming request
+
+    Returns:
+        Deferred
+
+    Raises:
+        AuthError if the requester is not an admin
+    """
+    requester = yield auth.get_user_by_req(request)
+    yield assert_user_is_admin(auth, requester.user)
+
+
+@defer.inlineCallbacks
+def assert_user_is_admin(auth, user_id):
+    """Verify that the given user is an admin user
+
+    WARNING: MAKE SURE YOU YIELD ON THE RESULT!
+
+    Args:
+        auth (synapse.api.auth.Auth):
+        user_id (UserID):
+
+    Returns:
+        Deferred
+
+    Raises:
+        AuthError if the user is not an admin
+    """
+
+    is_admin = yield auth.is_server_admin(user_id)
+    if not is_admin:
+        raise AuthError(403, "You are not a server admin")