handle SS /peek

federationapi/routing/peek.go

@@ -0,0 +1,112 @@
+// Copyright 2020 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.
+
+package routing
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/matrix-org/dendrite/clientapi/jsonerror"
+	"github.com/matrix-org/dendrite/internal/config"
+	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+)
+
+// Peek implements the /peek API
+func Peek(
+	httpReq *http.Request,
+	request *gomatrixserverlib.FederationRequest,
+	cfg *config.FederationAPI,
+	rsAPI api.RoomserverInternalAPI,
+	roomID, peekID string,
+	remoteVersions []gomatrixserverlib.RoomVersion,
+) util.JSONResponse {
+	verReq := api.QueryRoomVersionForRoomRequest{RoomID: roomID}
+	verRes := api.QueryRoomVersionForRoomResponse{}
+	if err := rsAPI.QueryRoomVersionForRoom(httpReq.Context(), &verReq, &verRes); err != nil {
+		return util.JSONResponse{
+			Code: http.StatusInternalServerError,
+			JSON: jsonerror.InternalServerError(),
+		}
+	}
+
+	// Check that the room that the remote side is trying to join is actually
+	// one of the room versions that they listed in their supported ?ver= in
+	// the peek URL.
+	remoteSupportsVersion := false
+	for _, v := range remoteVersions {
+		if v == verRes.RoomVersion {
+			remoteSupportsVersion = true
+			break
+		}
+	}
+	// If it isn't, stop trying to join the room.
+	if !remoteSupportsVersion {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.IncompatibleRoomVersion(verRes.RoomVersion),
+		}
+	}
+
+	// TODO: Check history visibility
+
+	state, err := getCurrentState(httpReq.Context(), request, rsAPI, roomID)
+	if err != nil {
+		return *err
+	}
+
+	return util.JSONResponse{
+		Code: http.StatusOK,
+		JSON: map[string]interface{}{
+			"state":        state,
+			"room_version": verRes.RoomVersion,
+		},
+	}
+}
+
+
+func getCurrentState(
+	ctx context.Context,
+	request *gomatrixserverlib.FederationRequest,
+	rsAPI api.RoomserverInternalAPI,
+	roomID string,
+) (*gomatrixserverlib.RespPeek, *util.JSONResponse) {
+	var response api.QueryStateAndAuthChainResponse
+	err := rsAPI.QueryStateAndAuthChain(
+		ctx,
+		&api.QueryStateAndAuthChainRequest{
+			RoomID:       roomID,
+			PrevEventIDs: []string{},
+			AuthEventIDs: []string{},
+		},
+		&response,
+	)
+	if err != nil {
+		resErr := util.ErrorResponse(err)
+		return nil, &resErr
+	}
+
+	if !response.RoomExists {
+		return nil, &util.JSONResponse{Code: http.StatusNotFound, JSON: nil}
+	}
+
+	return &gomatrixserverlib.RespPeek{
+		StateEvents: gomatrixserverlib.UnwrapEventHeaders(response.StateEvents),
+		AuthEvents:  gomatrixserverlib.UnwrapEventHeaders(response.AuthChainEvents),
+		RoomVersion: response.RoomVersion,
+		RenewalInterval: 60 * 60 * 1000 * 1000, // one hour
+	}, nil
+}

federationapi/routing/routing.go

@@ -207,7 +207,37 @@ func Setup(
 		},
 	)).Methods(http.MethodGet)
 
-	v1fedmux.Handle("/make_join/{roomID}/{eventID}", httputil.MakeFedAPI(
+	v1fedmux.Handle("/peek/{roomID}/{peekID}", httputil.MakeFedAPI(
+		"federation_peek", cfg.Matrix.ServerName, keys, wakeup,
+		func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
+			if roomserverAPI.IsServerBannedFromRoom(httpReq.Context(), rsAPI, vars["roomID"], request.Origin()) {
+				return util.JSONResponse{
+					Code: http.StatusForbidden,
+					JSON: jsonerror.Forbidden("Forbidden by server ACLs"),
+				}
+			}
+			roomID := vars["roomID"]
+			peekID := vars["peekID"]
+			queryVars := httpReq.URL.Query()
+			remoteVersions := []gomatrixserverlib.RoomVersion{}
+			if vers, ok := queryVars["ver"]; ok {
+				// The remote side supplied a ?ver= so use that to build up the list
+				// of supported room versions
+				for _, v := range vers {
+					remoteVersions = append(remoteVersions, gomatrixserverlib.RoomVersion(v))
+				}
+			} else {
+				// The remote side didn't supply a ?ver= so just assume that they only
+				// support room version 1
+				remoteVersions = append(remoteVersions, gomatrixserverlib.RoomVersionV1)
+			}
+			return Peek(
+				httpReq, request, cfg, rsAPI, roomID, peekID, remoteVersions,
+			)
+		},
+	)).Methods(http.MethodPut, http.MethodDelete)
+
+	v1fedmux.Handle("/make_join/{roomID}/{userID}", httputil.MakeFedAPI(
 		"federation_make_join", cfg.Matrix.ServerName, keys, wakeup,
 		func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest, vars map[string]string) util.JSONResponse {
 			if roomserverAPI.IsServerBannedFromRoom(httpReq.Context(), rsAPI, vars["roomID"], request.Origin()) {
@@ -217,7 +247,7 @@ func Setup(
 				}
 			}
 			roomID := vars["roomID"]
-			eventID := vars["eventID"]
+			userID := vars["userID"]
 			queryVars := httpReq.URL.Query()
 			remoteVersions := []gomatrixserverlib.RoomVersion{}
 			if vers, ok := queryVars["ver"]; ok {
@@ -233,7 +263,7 @@ func Setup(
 				remoteVersions = append(remoteVersions, gomatrixserverlib.RoomVersionV1)
 			}
 			return MakeJoin(
-				httpReq, request, cfg, rsAPI, roomID, eventID, remoteVersions,
+				httpReq, request, cfg, rsAPI, roomID, userID, remoteVersions,
 			)
 		},
 	)).Methods(http.MethodGet)