Implement content repository configuration endpoint

Fixes matrix-org#1303
Signed-off-by: Rudraksh Pareek <54525605+DelusionalOptimist@users.noreply.github.com>

mediaapi/routing/config.go

@@ -0,0 +1,37 @@
+// Copyright 2017 Vector Creations 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 (
+	"net/http"
+
+	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/util"
+)
+
+// mediaConfigResponse represents a response for a `config` request
+type mediaConfigResponse struct {
+	MaxFileSizeBytes *config.FileSizeBytes `json:"m.upload.size"`
+}
+
+// Config implements `/config` which allows clients to retrieve the
+// configuration of the content repository, such as upload limitations.
+// https://matrix.org/docs/spec/client_server/latest#get-matrix-media-r0-config
+func Config(req *http.Request, cfg *config.MediaAPI) util.JSONResponse {
+	return util.JSONResponse{
+		Code: http.StatusOK,
+		JSON: mediaConfigResponse{MaxFileSizeBytes: cfg.MaxFileSizeBytes},
+	}
+}

mediaapi/routing/routing.go

@@ -74,6 +74,12 @@ func Setup(
 	r0mux.Handle("/thumbnail/{serverName}/{mediaId}",
 		makeDownloadAPI("thumbnail", cfg, db, client, activeRemoteRequests, activeThumbnailGeneration),
 	).Methods(http.MethodGet, http.MethodOptions)
+
+	r0mux.Handle("/config",
+		httputil.MakeAuthAPI("config", userAPI, func(req *http.Request, dev *userapi.Device) util.JSONResponse {
+			return Config(req, cfg)
+		}),
+	).Methods(http.MethodGet, http.MethodOptions)
 }
 
 func makeDownloadAPI(

sytest-whitelist

@@ -511,3 +511,4 @@ Can pass a JSON filter as a query parameter
 Local room members can get room messages
 Remote room members can get room messages
 Guest users can send messages to guest_access rooms if joined
+Can read configuration endpoint