Implement forgetting about rooms (#1572)

* Add basic storage methods

* Add internal api handler

* Add check for forgotten room

* Add /rooms/{roomID}/forget endpoint

* Add missing rsAPI method

* Remove unused parameters

* Add passing tests

Signed-off-by: Till Faelligen <tfaelligen@gmail.com>

* Add missing file

* Add postgres migration

* Add sqlite migration

* Use Forgetter to forget room

* Remove empty line

* Update HTTP status codes

It looks like the spec calls for these to be 400, rather than 403: https://matrix.org/docs/spec/client_server/r0.6.1#post-matrix-client-r0-rooms-roomid-forget

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>

clientapi/routing/membership.go

@@ -407,3 +407,47 @@ func checkMemberInRoom(ctx context.Context, rsAPI api.RoomserverInternalAPI, use
 	}
 	return nil
 }
+
+func SendForget(
+	req *http.Request, device *userapi.Device,
+	roomID string, rsAPI roomserverAPI.RoomserverInternalAPI,
+) util.JSONResponse {
+	ctx := req.Context()
+	logger := util.GetLogger(ctx).WithField("roomID", roomID).WithField("userID", device.UserID)
+	var membershipRes api.QueryMembershipForUserResponse
+	membershipReq := api.QueryMembershipForUserRequest{
+		RoomID: roomID,
+		UserID: device.UserID,
+	}
+	err := rsAPI.QueryMembershipForUser(ctx, &membershipReq, &membershipRes)
+	if err != nil {
+		logger.WithError(err).Error("QueryMembershipForUser: could not query membership for user")
+		return jsonerror.InternalServerError()
+	}
+	if membershipRes.IsInRoom {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.Forbidden("user is still a member of the room"),
+		}
+	}
+	if !membershipRes.HasBeenInRoom {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.Forbidden("user did not belong to room"),
+		}
+	}
+
+	request := api.PerformForgetRequest{
+		RoomID: roomID,
+		UserID: device.UserID,
+	}
+	response := api.PerformForgetResponse{}
+	if err := rsAPI.PerformForget(ctx, &request, &response); err != nil {
+		logger.WithError(err).Error("PerformForget: unable to forget room")
+		return jsonerror.InternalServerError()
+	}
+	return util.JSONResponse{
+		Code: http.StatusOK,
+		JSON: struct{}{},
+	}
+}

clientapi/routing/routing.go

@@ -709,6 +709,19 @@ func Setup(
 		}),
 	).Methods(http.MethodPost, http.MethodOptions)
 
+	r0mux.Handle("/rooms/{roomID}/forget",
+		httputil.MakeAuthAPI("rooms_forget", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
+			if r := rateLimits.rateLimit(req); r != nil {
+				return *r
+			}
+			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
+			if err != nil {
+				return util.ErrorResponse(err)
+			}
+			return SendForget(req, device, vars["roomID"], rsAPI)
+		}),
+	).Methods(http.MethodPost, http.MethodOptions)
+
 	r0mux.Handle("/devices",
 		httputil.MakeAuthAPI("get_devices", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
 			return GetDevicesByLocalpart(req, userAPI, device)