Implement room_alias federation end point (#338)

* Add room alias query endpoint

* Try to fix indentation problems

* Fix linting errors and use of httpReq.FormValue

Signed-off-by: Ross Schulman <ross@rbs.io>

* Run gofmt

* Check for empty alias parameter and fix route URL

Signed-off-by: Ross Schulman <ross@rbs.io>

* Fix some linting errors

Signed-off-by: Ross Schulman <ross@rbs.io>

* Delete extra copy of directory route

src/github.com/matrix-org/dendrite/cmd/dendrite-federation-api-server/main.go

@@ -80,6 +80,7 @@ func main() {
 
 	queryAPI := api.NewRoomserverQueryAPIHTTP(cfg.RoomServerURL(), nil)
 	inputAPI := api.NewRoomserverInputAPIHTTP(cfg.RoomServerURL(), nil)
+	aliasAPI := api.NewRoomserverAliasAPIHTTP(cfg.RoomServerURL(), nil)
 
 	roomserverProducer := producers.NewRoomserverProducer(inputAPI)
 
@@ -90,7 +91,7 @@ func main() {
 	log.Info("Starting federation API server on ", cfg.Listen.FederationAPI)
 
 	api := mux.NewRouter()
-	routing.Setup(api, *cfg, queryAPI, roomserverProducer, keyRing, federation, accountDB)
+	routing.Setup(api, *cfg, queryAPI, aliasAPI, roomserverProducer, keyRing, federation, accountDB)
 	common.SetupHTTPAPI(http.DefaultServeMux, api)
 
 	log.Fatal(http.ListenAndServe(string(cfg.Listen.FederationAPI), nil))

src/github.com/matrix-org/dendrite/cmd/dendrite-monolith-server/main.go

@@ -348,7 +348,7 @@ func (m *monolith) setupAPIs() {
 	), m.syncAPIDB, m.deviceDB)
 
 	federationapi_routing.Setup(
-		m.api, *m.cfg, m.queryAPI, m.roomServerProducer, m.keyRing, m.federation,
+		m.api, *m.cfg, m.queryAPI, m.aliasAPI, m.roomServerProducer, m.keyRing, m.federation,
 		m.accountDB,
 	)
 

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

@@ -0,0 +1,96 @@
+// 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 (
+	"fmt"
+	"net/http"
+
+	"github.com/matrix-org/dendrite/clientapi/httputil"
+	"github.com/matrix-org/dendrite/clientapi/jsonerror"
+	"github.com/matrix-org/dendrite/common/config"
+	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/gomatrix"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+)
+
+// RoomAliasToID converts the queried alias into a room ID and returns it
+func RoomAliasToID(
+	httpReq *http.Request,
+	federation *gomatrixserverlib.FederationClient,
+	cfg config.Dendrite,
+	aliasAPI api.RoomserverAliasAPI,
+) util.JSONResponse {
+	roomAlias := httpReq.FormValue("alias")
+	if roomAlias == "" {
+		return util.JSONResponse{
+			Code: 400,
+			JSON: jsonerror.BadJSON("Must supply room alias parameter."),
+		}
+	}
+	_, domain, err := gomatrixserverlib.SplitID('#', roomAlias)
+	if err != nil {
+		return util.JSONResponse{
+			Code: 400,
+			JSON: jsonerror.BadJSON("Room alias must be in the form '#localpart:domain'"),
+		}
+	}
+
+	var resp gomatrixserverlib.RespDirectory
+
+	if domain == cfg.Matrix.ServerName {
+		queryReq := api.GetAliasRoomIDRequest{Alias: roomAlias}
+		var queryRes api.GetAliasRoomIDResponse
+		if err = aliasAPI.GetAliasRoomID(httpReq.Context(), &queryReq, &queryRes); err != nil {
+			return httputil.LogThenError(httpReq, err)
+		}
+
+		if queryRes.RoomID == "" {
+			// TODO: List servers that are aware of this room alias
+			resp = gomatrixserverlib.RespDirectory{
+				RoomID:  queryRes.RoomID,
+				Servers: []gomatrixserverlib.ServerName{},
+			}
+		} else {
+			// If the response doesn't contain a non-empty string, return an error
+			return util.JSONResponse{
+				Code: 404,
+				JSON: jsonerror.NotFound(fmt.Sprintf("Room alias %s not found", roomAlias)),
+			}
+		}
+	} else {
+		resp, err = federation.LookupRoomAlias(httpReq.Context(), domain, roomAlias)
+		if err != nil {
+			switch x := err.(type) {
+			case gomatrix.HTTPError:
+				if x.Code == 404 {
+					return util.JSONResponse{
+						Code: 404,
+						JSON: jsonerror.NotFound("Room alias not found"),
+					}
+				}
+			}
+			// TODO: Return 502 if the remote server errored.
+			// TODO: Return 504 if the remote server timed out.
+			return httputil.LogThenError(httpReq, err)
+		}
+	}
+
+	return util.JSONResponse{
+		Code: 200,
+		JSON: resp,
+	}
+}

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

@@ -38,6 +38,7 @@ func Setup(
 	apiMux *mux.Router,
 	cfg config.Dendrite,
 	query api.RoomserverQueryAPI,
+	aliasAPI api.RoomserverAliasAPI,
 	producer *producers.RoomserverProducer,
 	keys gomatrixserverlib.KeyRing,
 	federation *gomatrixserverlib.FederationClient,
@@ -105,6 +106,15 @@ func Setup(
 		},
 	)).Methods("GET")
 
+	v1fedmux.Handle("/query/directory/", common.MakeFedAPI(
+		"federation_query_room_alias", cfg.Matrix.ServerName, keys,
+		func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {
+			return RoomAliasToID(
+				httpReq, federation, cfg, aliasAPI,
+			)
+		},
+	)).Methods("GET")
+
 	v1fedmux.Handle("/query/profile", common.MakeFedAPI(
 		"federation_query_profile", cfg.Matrix.ServerName, keys,
 		func(httpReq *http.Request, request *gomatrixserverlib.FederationRequest) util.JSONResponse {