Add a return type to parse_string. (#10438)

And set the required attribute in a few places which will error if
a parameter is not provided.

4 files changed, 30 insertions, 24 deletions

diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index c95c5ae234..5d309a534c 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -413,7 +413,7 @@ class RoomBatchSendEventRestServlet(TransactionRestServlet):
         assert_params_in_dict(body, ["state_events_at_start", "events"])
 
         prev_events_from_query = parse_strings_from_args(request.args, "prev_event")
-        chunk_id_from_query = parse_string(request, "chunk_id", default=None)
+        chunk_id_from_query = parse_string(request, "chunk_id")
 
         if prev_events_from_query is None:
             raise SynapseError(
@@ -735,7 +735,7 @@ class PublicRoomListRestServlet(TransactionRestServlet):
         self.auth = hs.get_auth()
 
     async def on_GET(self, request):
-        server = parse_string(request, "server", default=None)
+        server = parse_string(request, "server")
 
         try:
             await self.auth.get_user_by_req(request, allow_guest=True)
@@ -755,7 +755,7 @@ class PublicRoomListRestServlet(TransactionRestServlet):
                 raise e
 
         limit = parse_integer(request, "limit", 0)
-        since_token = parse_string(request, "since", None)
+        since_token = parse_string(request, "since")
 
         if limit == 0:
             # zero is a special value which corresponds to no limit.
@@ -789,7 +789,7 @@ class PublicRoomListRestServlet(TransactionRestServlet):
     async def on_POST(self, request):
         await self.auth.get_user_by_req(request, allow_guest=True)
 
-        server = parse_string(request, "server", default=None)
+        server = parse_string(request, "server")
         content = parse_json_object_from_request(request)
 
         limit: Optional[int] = int(content.get("limit", 100))
diff --git a/synapse/rest/client/v2_alpha/keys.py b/synapse/rest/client/v2_alpha/keys.py
index 33cf8de186..d0d9d30d40 100644
--- a/synapse/rest/client/v2_alpha/keys.py
+++ b/synapse/rest/client/v2_alpha/keys.py
@@ -194,7 +194,7 @@ class KeyChangesServlet(RestServlet):
     async def on_GET(self, request):
         requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        from_token_string = parse_string(request, "from")
+        from_token_string = parse_string(request, "from", required=True)
         set_tag("from", from_token_string)
 
         # We want to enforce they do pass us one, but we ignore it and return
diff --git a/synapse/rest/client/v2_alpha/relations.py b/synapse/rest/client/v2_alpha/relations.py
index c7da6759db..0821cd285f 100644
--- a/synapse/rest/client/v2_alpha/relations.py
+++ b/synapse/rest/client/v2_alpha/relations.py
@@ -158,19 +158,21 @@ class RelationPaginationServlet(RestServlet):
         event = await self.event_handler.get_event(requester.user, room_id, parent_id)
 
         limit = parse_integer(request, "limit", default=5)
-        from_token = parse_string(request, "from")
-        to_token = parse_string(request, "to")
+        from_token_str = parse_string(request, "from")
+        to_token_str = parse_string(request, "to")
 
         if event.internal_metadata.is_redacted():
             # If the event is redacted, return an empty list of relations
             pagination_chunk = PaginationChunk(chunk=[])
         else:
             # Return the relations
-            if from_token:
-                from_token = RelationPaginationToken.from_string(from_token)
+            from_token = None
+            if from_token_str:
+                from_token = RelationPaginationToken.from_string(from_token_str)
 
-            if to_token:
-                to_token = RelationPaginationToken.from_string(to_token)
+            to_token = None
+            if to_token_str:
+                to_token = RelationPaginationToken.from_string(to_token_str)
 
             pagination_chunk = await self.store.get_relations_for_event(
                 event_id=parent_id,
@@ -256,19 +258,21 @@ class RelationAggregationPaginationServlet(RestServlet):
             raise SynapseError(400, "Relation type must be 'annotation'")
 
         limit = parse_integer(request, "limit", default=5)
-        from_token = parse_string(request, "from")
-        to_token = parse_string(request, "to")
+        from_token_str = parse_string(request, "from")
+        to_token_str = parse_string(request, "to")
 
         if event.internal_metadata.is_redacted():
             # If the event is redacted, return an empty list of relations
             pagination_chunk = PaginationChunk(chunk=[])
         else:
             # Return the relations
-            if from_token:
-                from_token = AggregationPaginationToken.from_string(from_token)
+            from_token = None
+            if from_token_str:
+                from_token = AggregationPaginationToken.from_string(from_token_str)
 
-            if to_token:
-                to_token = AggregationPaginationToken.from_string(to_token)
+            to_token = None
+            if to_token_str:
+                to_token = AggregationPaginationToken.from_string(to_token_str)
 
             pagination_chunk = await self.store.get_aggregation_groups_for_event(
                 event_id=parent_id,
@@ -336,14 +340,16 @@ class RelationAggregationGroupPaginationServlet(RestServlet):
             raise SynapseError(400, "Relation type must be 'annotation'")
 
         limit = parse_integer(request, "limit", default=5)
-        from_token = parse_string(request, "from")
-        to_token = parse_string(request, "to")
+        from_token_str = parse_string(request, "from")
+        to_token_str = parse_string(request, "to")
 
-        if from_token:
-            from_token = RelationPaginationToken.from_string(from_token)
+        from_token = None
+        if from_token_str:
+            from_token = RelationPaginationToken.from_string(from_token_str)
 
-        if to_token:
-            to_token = RelationPaginationToken.from_string(to_token)
+        to_token = None
+        if to_token_str:
+            to_token = RelationPaginationToken.from_string(to_token_str)
 
         result = await self.store.get_relations_for_event(
             event_id=parent_id,
diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index ecbbcf3851..7bb4e6b8aa 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -112,7 +112,7 @@ class SyncRestServlet(RestServlet):
             default="online",
             allowed_values=self.ALLOWED_PRESENCE,
         )
-        filter_id = parse_string(request, "filter", default=None)
+        filter_id = parse_string(request, "filter")
         full_state = parse_boolean(request, "full_state", default=False)
 
         logger.debug(