Add event reporting (#3340)

Part of #3216 and #3226 

There will be a follow up PR which is going to add the same admin
endpoints Synapse has, so existing tools also work for Dendrite.

clientapi/routing/report_event.go

@@ -0,0 +1,93 @@
+// Copyright 2023 The Matrix.org Foundation C.I.C.
+//
+// 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.
+
+package routing
+
+import (
+	"net/http"
+
+	"github.com/matrix-org/dendrite/clientapi/httputil"
+	"github.com/matrix-org/dendrite/roomserver/api"
+	userAPI "github.com/matrix-org/dendrite/userapi/api"
+	"github.com/matrix-org/gomatrixserverlib/spec"
+	"github.com/matrix-org/util"
+)
+
+type reportEventRequest struct {
+	Reason string `json:"reason"`
+	Score  int64  `json:"score"`
+}
+
+func ReportEvent(
+	req *http.Request,
+	device *userAPI.Device,
+	roomID, eventID string,
+	rsAPI api.ClientRoomserverAPI,
+) util.JSONResponse {
+	defer req.Body.Close() // nolint: errcheck
+
+	deviceUserID, err := spec.NewUserID(device.UserID, true)
+	if err != nil {
+		return util.JSONResponse{
+			Code: http.StatusForbidden,
+			JSON: spec.NotFound("You don't have permission to report this event, bad userID"),
+		}
+	}
+	// The requesting user must be a member of the room
+	errRes := checkMemberInRoom(req.Context(), rsAPI, *deviceUserID, roomID)
+	if errRes != nil {
+		return util.JSONResponse{
+			Code: http.StatusNotFound, // Spec demands this...
+			JSON: spec.NotFound("The event was not found or you are not joined to the room."),
+		}
+	}
+
+	// Parse the request
+	report := reportEventRequest{}
+	if resErr := httputil.UnmarshalJSONRequest(req, &report); resErr != nil {
+		return *resErr
+	}
+
+	queryRes := &api.QueryEventsByIDResponse{}
+	if err = rsAPI.QueryEventsByID(req.Context(), &api.QueryEventsByIDRequest{
+		RoomID:   roomID,
+		EventIDs: []string{eventID},
+	}, queryRes); err != nil {
+		return util.JSONResponse{
+			Code: http.StatusInternalServerError,
+			JSON: spec.InternalServerError{Err: err.Error()},
+		}
+	}
+
+	// No event was found or it was already redacted
+	if len(queryRes.Events) == 0 || queryRes.Events[0].Redacted() {
+		return util.JSONResponse{
+			Code: http.StatusNotFound,
+			JSON: spec.NotFound("The event was not found or you are not joined to the room."),
+		}
+	}
+
+	_, err = rsAPI.InsertReportedEvent(req.Context(), roomID, eventID, device.UserID, report.Reason, report.Score)
+	if err != nil {
+		return util.JSONResponse{
+			Code: http.StatusInternalServerError,
+			JSON: spec.InternalServerError{Err: err.Error()},
+		}
+	}
+
+	return util.JSONResponse{
+		Code: http.StatusOK,
+		JSON: struct{}{},
+	}
+}

clientapi/routing/routing.go

@@ -1523,4 +1523,14 @@ func Setup(
 			return GetJoinedMembers(req, device, vars["roomID"], rsAPI)
 		}),
 	).Methods(http.MethodGet, http.MethodOptions)
+
+	v3mux.Handle("/rooms/{roomID}/report/{eventID}",
+		httputil.MakeAuthAPI("report_event", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
+			vars, err := httputil.URLDecodeMapValues(mux.Vars(req))
+			if err != nil {
+				return util.ErrorResponse(err)
+			}
+			return ReportEvent(req, device, vars["roomID"], vars["eventID"], rsAPI)
+		}),
+	).Methods(http.MethodPost, http.MethodOptions)
 }