[roomserver] Add internal API QueryMembershipForUser (#544)

* Add internal API QueryMembershipForUser

Signed-off-by: Anant Prakash <anantprakashjsr@gmail.com>

* Change sender to user_id

src/github.com/matrix-org/dendrite/roomserver/api/query.go

@@ -104,6 +104,25 @@ type QueryEventsByIDResponse struct {
 	Events []gomatrixserverlib.Event `json:"events"`
 }
 
+// QueryMembershipForUserRequest is a request to QueryMembership
+type QueryMembershipForUserRequest struct {
+	// ID of the room to fetch membership from
+	RoomID string `json:"room_id"`
+	// ID of the user for whom membership is requested
+	UserID string `json:"user_id"`
+}
+
+// QueryMembershipForUserResponse is a response to QueryMembership
+type QueryMembershipForUserResponse struct {
+	// The EventID of the latest "m.room.member" event for the sender,
+	// if HasBeenInRoom is true.
+	EventID string `json:"event_id"`
+	// True if the user has been in room before and has either stayed in it or left it.
+	HasBeenInRoom bool `json:"has_been_in_room"`
+	// True if the user is in room.
+	IsInRoom bool `json:"is_in_room"`
+}
+
 // QueryMembershipsForRoomRequest is a request to QueryMembershipsForRoom
 type QueryMembershipsForRoomRequest struct {
 	// If true, only returns the membership events of "join" membership
@@ -222,6 +241,13 @@ type RoomserverQueryAPI interface {
 		response *QueryEventsByIDResponse,
 	) error
 
+	// Query the membership event for an user for a room.
+	QueryMembershipForUser(
+		ctx context.Context,
+		request *QueryMembershipForUserRequest,
+		response *QueryMembershipForUserResponse,
+	) error
+
 	// Query a list of membership events for a room
 	QueryMembershipsForRoom(
 		ctx context.Context,
@@ -269,6 +295,9 @@ const RoomserverQueryStateAfterEventsPath = "/api/roomserver/queryStateAfterEven
 // RoomserverQueryEventsByIDPath is the HTTP path for the QueryEventsByID API.
 const RoomserverQueryEventsByIDPath = "/api/roomserver/queryEventsByID"
 
+// RoomserverQueryMembershipForUserPath is the HTTP path for the QueryMembershipForUser API.
+const RoomserverQueryMembershipForUserPath = "/api/roomserver/queryMembershipForUser"
+
 // RoomserverQueryMembershipsForRoomPath is the HTTP path for the QueryMembershipsForRoom API
 const RoomserverQueryMembershipsForRoomPath = "/api/roomserver/queryMembershipsForRoom"
 
@@ -337,6 +366,19 @@ func (h *httpRoomserverQueryAPI) QueryEventsByID(
 	return postJSON(ctx, span, h.httpClient, apiURL, request, response)
 }
 
+// QueryMembershipForUser implements RoomserverQueryAPI
+func (h *httpRoomserverQueryAPI) QueryMembershipForUser(
+	ctx context.Context,
+	request *QueryMembershipForUserRequest,
+	response *QueryMembershipForUserResponse,
+) error {
+	span, ctx := opentracing.StartSpanFromContext(ctx, "QueryMembershipForUser")
+	defer span.Finish()
+
+	apiURL := h.roomserverURL + RoomserverQueryMembershipForUserPath
+	return postJSON(ctx, span, h.httpClient, apiURL, request, response)
+}
+
 // QueryMembershipsForRoom implements RoomserverQueryAPI
 func (h *httpRoomserverQueryAPI) QueryMembershipsForRoom(
 	ctx context.Context,

src/github.com/matrix-org/dendrite/roomserver/query/query.go

@@ -227,6 +227,37 @@ func (r *RoomserverQueryAPI) loadEvents(
 	return result, nil
 }
 
+// QueryMembershipForUser implements api.RoomserverQueryAPI
+func (r *RoomserverQueryAPI) QueryMembershipForUser(
+	ctx context.Context,
+	request *api.QueryMembershipForUserRequest,
+	response *api.QueryMembershipForUserResponse,
+) error {
+	roomNID, err := r.DB.RoomNID(ctx, request.RoomID)
+	if err != nil {
+		return err
+	}
+
+	membershipEventNID, stillInRoom, err := r.DB.GetMembership(ctx, roomNID, request.UserID)
+	if err != nil {
+		return err
+	}
+
+	if membershipEventNID == 0 {
+		response.HasBeenInRoom = false
+		return nil
+	}
+
+	response.IsInRoom = stillInRoom
+	eventIDMap, err := r.DB.EventIDs(ctx, []types.EventNID{membershipEventNID})
+	if err != nil {
+		return err
+	}
+
+	response.EventID = eventIDMap[membershipEventNID]
+	return nil
+}
+
 // QueryMembershipsForRoom implements api.RoomserverQueryAPI
 func (r *RoomserverQueryAPI) QueryMembershipsForRoom(
 	ctx context.Context,
@@ -593,6 +624,20 @@ func (r *RoomserverQueryAPI) SetupHTTP(servMux *http.ServeMux) {
 			return util.JSONResponse{Code: http.StatusOK, JSON: &response}
 		}),
 	)
+	servMux.Handle(
+		api.RoomserverQueryMembershipForUserPath,
+		common.MakeInternalAPI("QueryMembershipForUser", func(req *http.Request) util.JSONResponse {
+			var request api.QueryMembershipForUserRequest
+			var response api.QueryMembershipForUserResponse
+			if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
+				return util.ErrorResponse(err)
+			}
+			if err := r.QueryMembershipForUser(req.Context(), &request, &response); err != nil {
+				return util.ErrorResponse(err)
+			}
+			return util.JSONResponse{Code: http.StatusOK, JSON: &response}
+		}),
+	)
 	servMux.Handle(
 		api.RoomserverQueryMembershipsForRoomPath,
 		common.MakeInternalAPI("queryMembershipsForRoom", func(req *http.Request) util.JSONResponse {