Implement /make_join and /send_join (#316)

src/github.com/matrix-org/dendrite/common/events.go

@@ -42,11 +42,32 @@ func BuildEvent(
 	builder *gomatrixserverlib.EventBuilder, cfg config.Dendrite,
 	queryAPI api.RoomserverQueryAPI, queryRes *api.QueryLatestEventsAndStateResponse,
 ) (*gomatrixserverlib.Event, error) {
-	eventsNeeded, err := gomatrixserverlib.StateNeededForEventBuilder(builder)
+	err := AddPrevEventsToEvent(ctx, builder, queryAPI, queryRes)
 	if err != nil {
 		return nil, err
 	}
 
+	eventID := fmt.Sprintf("$%s:%s", util.RandomString(16), cfg.Matrix.ServerName)
+	now := time.Now()
+	event, err := builder.Build(eventID, now, cfg.Matrix.ServerName, cfg.Matrix.KeyID, cfg.Matrix.PrivateKey)
+	if err != nil {
+		return nil, err
+	}
+
+	return &event, nil
+}
+
+// AddPrevEventsToEvent fills out the prev_events and auth_events fields in EventBuilder
+func AddPrevEventsToEvent(
+	ctx context.Context,
+	builder *gomatrixserverlib.EventBuilder,
+	queryAPI api.RoomserverQueryAPI, queryRes *api.QueryLatestEventsAndStateResponse,
+) error {
+	eventsNeeded, err := gomatrixserverlib.StateNeededForEventBuilder(builder)
+	if err != nil {
+		return err
+	}
+
 	// Ask the roomserver for information about this room
 	queryReq := api.QueryLatestEventsAndStateRequest{
 		RoomID:       builder.RoomID,
@@ -56,11 +77,11 @@ func BuildEvent(
 		queryRes = &api.QueryLatestEventsAndStateResponse{}
 	}
 	if err = queryAPI.QueryLatestEventsAndState(ctx, &queryReq, queryRes); err != nil {
-		return nil, err
+		return err
 	}
 
 	if !queryRes.RoomExists {
-		return nil, ErrRoomNoExists
+		return ErrRoomNoExists
 	}
 
 	builder.Depth = queryRes.Depth
@@ -71,22 +92,15 @@ func BuildEvent(
 	for i := range queryRes.StateEvents {
 		err = authEvents.AddEvent(&queryRes.StateEvents[i])
 		if err != nil {
-			return nil, err
+			return err
 		}
 	}
 
 	refs, err := eventsNeeded.AuthEventReferences(&authEvents)
 	if err != nil {
-		return nil, err
+		return err
 	}
 	builder.AuthEvents = refs
 
-	eventID := fmt.Sprintf("$%s:%s", util.RandomString(16), cfg.Matrix.ServerName)
-	now := time.Now()
-	event, err := builder.Build(eventID, now, cfg.Matrix.ServerName, cfg.Matrix.KeyID, cfg.Matrix.PrivateKey)
-	if err != nil {
-		return nil, err
-	}
-
-	return &event, nil
+	return nil
 }

src/github.com/matrix-org/dendrite/federationapi/routing/join.go

@@ -0,0 +1,184 @@
+// Copyright 2017 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"
+	"encoding/json"
+	"net/http"
+
+	"github.com/matrix-org/dendrite/clientapi/httputil"
+	"github.com/matrix-org/dendrite/clientapi/jsonerror"
+	"github.com/matrix-org/dendrite/clientapi/producers"
+	"github.com/matrix-org/dendrite/common"
+	"github.com/matrix-org/dendrite/common/config"
+	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+)
+
+// MakeJoin implements the /make_join API
+func MakeJoin(
+	ctx context.Context,
+	httpReq *http.Request,
+	request *gomatrixserverlib.FederationRequest,
+	cfg config.Dendrite,
+	query api.RoomserverQueryAPI,
+	roomID, userID string,
+) util.JSONResponse {
+	_, domain, err := gomatrixserverlib.SplitID('@', userID)
+	if err != nil {
+		return util.JSONResponse{
+			Code: 400,
+			JSON: jsonerror.BadJSON("Invalid UserID"),
+		}
+	}
+	if domain != request.Origin() {
+		return util.JSONResponse{
+			Code: 403,
+			JSON: jsonerror.Forbidden("The join must be sent by the server of the user"),
+		}
+	}
+
+	// Try building an event for the server
+	builder := gomatrixserverlib.EventBuilder{
+		Sender:   userID,
+		RoomID:   roomID,
+		Type:     "m.room.member",
+		StateKey: &userID,
+	}
+	err = builder.SetContent(map[string]interface{}{"membership": "join"})
+	if err != nil {
+		return httputil.LogThenError(httpReq, err)
+	}
+
+	var queryRes api.QueryLatestEventsAndStateResponse
+	event, err := common.BuildEvent(ctx, &builder, cfg, query, &queryRes)
+	if err == common.ErrRoomNoExists {
+		return util.JSONResponse{
+			Code: 404,
+			JSON: jsonerror.NotFound("Room does not exist"),
+		}
+	} else if err != nil {
+		return httputil.LogThenError(httpReq, err)
+	}
+
+	// Check that the join is allowed or not
+	stateEvents := make([]*gomatrixserverlib.Event, len(queryRes.StateEvents))
+	for i := range queryRes.StateEvents {
+		stateEvents[i] = &queryRes.StateEvents[i]
+	}
+	provider := gomatrixserverlib.NewAuthEvents(stateEvents)
+	if err = gomatrixserverlib.Allowed(*event, &provider); err != nil {
+		return util.JSONResponse{
+			Code: 403,
+			JSON: jsonerror.Forbidden(err.Error()),
+		}
+	}
+
+	return util.JSONResponse{
+		Code: 200,
+		JSON: map[string]interface{}{"event": builder},
+	}
+}
+
+// SendJoin implements the /send_join API
+func SendJoin(
+	ctx context.Context,
+	httpReq *http.Request,
+	request *gomatrixserverlib.FederationRequest,
+	cfg config.Dendrite,
+	query api.RoomserverQueryAPI,
+	producer *producers.RoomserverProducer,
+	keys gomatrixserverlib.KeyRing,
+	roomID, eventID string,
+) util.JSONResponse {
+	var event gomatrixserverlib.Event
+	if err := json.Unmarshal(request.Content(), &event); err != nil {
+		return util.JSONResponse{
+			Code: 400,
+			JSON: jsonerror.NotJSON("The request body could not be decoded into valid JSON. " + err.Error()),
+		}
+	}
+
+	// Check that the room ID is correct.
+	if event.RoomID() != roomID {
+		return util.JSONResponse{
+			Code: 400,
+			JSON: jsonerror.BadJSON("The room ID in the request path must match the room ID in the join event JSON"),
+		}
+	}
+
+	// Check that the event ID is correct.
+	if event.EventID() != eventID {
+		return util.JSONResponse{
+			Code: 400,
+			JSON: jsonerror.BadJSON("The event ID in the request path must match the event ID in the join event JSON"),
+		}
+	}
+
+	// Check that the event is from the server sending the request.
+	if event.Origin() != request.Origin() {
+		return util.JSONResponse{
+			Code: 403,
+			JSON: jsonerror.Forbidden("The join must be sent by the server it originated on"),
+		}
+	}
+
+	// Check that the event is signed by the server sending the request.
+	verifyRequests := []gomatrixserverlib.VerifyJSONRequest{{
+		ServerName: event.Origin(),
+		Message:    event.Redact().JSON(),
+		AtTS:       event.OriginServerTS(),
+	}}
+	verifyResults, err := keys.VerifyJSONs(ctx, verifyRequests)
+	if err != nil {
+		return httputil.LogThenError(httpReq, err)
+	}
+	if verifyResults[0].Error != nil {
+		return util.JSONResponse{
+			Code: 403,
+			JSON: jsonerror.Forbidden("The join must be signed by the server it originated on"),
+		}
+	}
+
+	// Fetch the state and auth chain. We do this before we send the events
+	// on, in case this fails.
+	var stateAndAuthChainRepsonse api.QueryStateAndAuthChainResponse
+	err = query.QueryStateAndAuthChain(ctx, &api.QueryStateAndAuthChainRequest{
+		PrevEventIDs: event.PrevEventIDs(),
+		AuthEventIDs: event.AuthEventIDs(),
+		RoomID:       roomID,
+	}, &stateAndAuthChainRepsonse)
+	if err != nil {
+		return httputil.LogThenError(httpReq, err)
+	}
+
+	// Send the events to the room server.
+	// We are responsible for notifying other servers that the user has joined
+	// the room, so set SendAsServer to cfg.Matrix.ServerName
+	err = producer.SendEvents(ctx, []gomatrixserverlib.Event{event}, cfg.Matrix.ServerName)
+	if err != nil {
+		return httputil.LogThenError(httpReq, err)
+	}
+
+	return util.JSONResponse{
+		Code: 200,
+		JSON: map[string]interface{}{
+			"state":      stateAndAuthChainRepsonse.StateEvents,
+			"auth_chain": stateAndAuthChainRepsonse.AuthChainEvents,
+		},
+	}
+}

src/github.com/matrix-org/dendrite/federationapi/routing/routing.go

@@ -124,6 +124,30 @@ func Setup(
 		},
 	)).Methods("GET")
 
+	v1fedmux.Handle("/make_join/{roomID}/{userID}", common.MakeFedAPI(
+		"federation_make_join", cfg.Matrix.ServerName, keys,
+		func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
+			vars := mux.Vars(httpReq)
+			roomID := vars["roomID"]
+			userID := vars["userID"]
+			return MakeJoin(
+				httpReq.Context(), httpReq, request, cfg, query, roomID, userID,
+			)
+		},
+	)).Methods("GET")
+
+	v1fedmux.Handle("/send_join/{roomID}/{userID}", common.MakeFedAPI(
+		"federation_send_join", cfg.Matrix.ServerName, keys,
+		func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
+			vars := mux.Vars(httpReq)
+			roomID := vars["roomID"]
+			userID := vars["userID"]
+			return SendJoin(
+				httpReq.Context(), httpReq, request, cfg, query, producer, keys, roomID, userID,
+			)
+		},
+	)).Methods("PUT")
+
 	v1fedmux.Handle("/version", common.MakeExternalAPI(
 		"federation_version",
 		func(httpReq *http.Request) util.JSONResponse {