Add support for MSC3916 endpoints for direct media

directmedia.go

@@ -25,8 +25,10 @@ import (
 	"fmt"
 	"io"
 	"mime"
+	"mime/multipart"
 	"net"
 	"net/http"
+	"net/textproto"
 	"net/url"
 	"os"
 	"strconv"
@@ -110,9 +112,11 @@ func newDirectMediaAPI(br *DiscordBridge) *DirectMediaAPI {
 	if dma.ks.WellKnownTarget == "" {
 		dma.ks.WellKnownTarget = fmt.Sprintf("%s:443", dma.cfg.ServerName)
 	}
+	federationRouter := r.PathPrefix("/_matrix/federation").Subrouter()
 	mediaRouter := r.PathPrefix("/_matrix/media").Subrouter()
+	clientMediaRouter := r.PathPrefix("/_matrix/client/v1/media").Subrouter()
 	var reqIDCounter atomic.Uint64
-	mediaRouter.Use(func(next http.Handler) http.Handler {
+	middleware := func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			w.Header().Set("Access-Control-Allow-Origin", "*")
 			w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
@@ -124,21 +128,37 @@ func newDirectMediaAPI(br *DiscordBridge) *DirectMediaAPI {
 				Logger()
 			next.ServeHTTP(w, r.WithContext(log.WithContext(r.Context())))
 		})
-	})
+	}
+	mediaRouter.Use(middleware)
+	federationRouter.Use(middleware)
+	clientMediaRouter.Use(middleware)
 	addRoutes := func(version string) {
 		mediaRouter.HandleFunc("/"+version+"/download/{serverName}/{mediaID}", dma.DownloadMedia).Methods(http.MethodGet)
 		mediaRouter.HandleFunc("/"+version+"/download/{serverName}/{mediaID}/{fileName}", dma.DownloadMedia).Methods(http.MethodGet)
 		mediaRouter.HandleFunc("/"+version+"/thumbnail/{serverName}/{mediaID}", dma.DownloadMedia).Methods(http.MethodGet)
 		mediaRouter.HandleFunc("/"+version+"/upload/{serverName}/{mediaID}", dma.UploadNotSupported).Methods(http.MethodPut)
 		mediaRouter.HandleFunc("/"+version+"/upload", dma.UploadNotSupported).Methods(http.MethodPost)
+		mediaRouter.HandleFunc("/"+version+"/create", dma.UploadNotSupported).Methods(http.MethodPost)
 		mediaRouter.HandleFunc("/"+version+"/config", dma.UploadNotSupported).Methods(http.MethodGet)
 		mediaRouter.HandleFunc("/"+version+"/preview_url", dma.PreviewURLNotSupported).Methods(http.MethodGet)
 	}
+	clientMediaRouter.HandleFunc("/download/{serverName}/{mediaID}", dma.DownloadMedia).Methods(http.MethodGet)
+	clientMediaRouter.HandleFunc("/download/{serverName}/{mediaID}/{fileName}", dma.DownloadMedia).Methods(http.MethodGet)
+	clientMediaRouter.HandleFunc("/thumbnail/{serverName}/{mediaID}", dma.DownloadMedia).Methods(http.MethodGet)
+	clientMediaRouter.HandleFunc("/upload/{serverName}/{mediaID}", dma.UploadNotSupported).Methods(http.MethodPut)
+	clientMediaRouter.HandleFunc("/upload", dma.UploadNotSupported).Methods(http.MethodPost)
+	clientMediaRouter.HandleFunc("/create", dma.UploadNotSupported).Methods(http.MethodPost)
+	clientMediaRouter.HandleFunc("/config", dma.UploadNotSupported).Methods(http.MethodGet)
+	clientMediaRouter.HandleFunc("/preview_url", dma.PreviewURLNotSupported).Methods(http.MethodGet)
 	addRoutes("v3")
 	addRoutes("r0")
 	addRoutes("v1")
+	federationRouter.HandleFunc("/v1/media/download/{mediaID}", dma.DownloadMedia).Methods(http.MethodGet)
+	federationRouter.HandleFunc("/v1/version", dma.ks.GetServerVersion).Methods(http.MethodGet)
 	mediaRouter.NotFoundHandler = http.HandlerFunc(dma.UnknownEndpoint)
 	mediaRouter.MethodNotAllowedHandler = http.HandlerFunc(dma.UnsupportedMethod)
+	federationRouter.NotFoundHandler = http.HandlerFunc(dma.UnknownEndpoint)
+	federationRouter.MethodNotAllowedHandler = http.HandlerFunc(dma.UnsupportedMethod)
 	dma.ks.Register(r)
 
 	return dma
@@ -532,14 +552,17 @@ func (dma *DirectMediaAPI) proxyDownload(ctx context.Context, w http.ResponseWri
 func (dma *DirectMediaAPI) DownloadMedia(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
 	log := zerolog.Ctx(ctx)
+	isNewFederation := strings.HasPrefix(r.URL.Path, "/_matrix/federation/v1/media/download/")
 	vars := mux.Vars(r)
-	if vars["serverName"] != dma.cfg.ServerName {
+	if !isNewFederation && vars["serverName"] != dma.cfg.ServerName {
 		jsonResponse(w, http.StatusNotFound, &mautrix.RespError{
 			ErrCode: mautrix.MNotFound.ErrCode,
 			Err:     fmt.Sprintf("This is a Discord media proxy for %q, other media downloads are not available here", dma.cfg.ServerName),
 		})
 		return
 	}
+	// TODO check destination header in X-Matrix auth when isNewFederation
+
 	url, expiresAt, err := dma.getMediaURL(ctx, vars["mediaID"])
 	if err != nil {
 		var respError *RespError
@@ -556,7 +579,36 @@ func (dma *DirectMediaAPI) DownloadMedia(w http.ResponseWriter, r *http.Request)
 			})
 		}
 		return
-
+	}
+	if isNewFederation {
+		mp := multipart.NewWriter(w)
+		w.Header().Set("Content-Type", strings.Replace(mp.FormDataContentType(), "form-data", "mixed", 1))
+		var metaPart io.Writer
+		metaPart, err = mp.CreatePart(textproto.MIMEHeader{
+			"Content-Type": {"application/json"},
+		})
+		if err != nil {
+			log.Err(err).Msg("Failed to create multipart metadata field")
+			return
+		}
+		_, err = metaPart.Write([]byte(`{}`))
+		if err != nil {
+			log.Err(err).Msg("Failed to write multipart metadata field")
+			return
+		}
+		_, err = mp.CreatePart(textproto.MIMEHeader{
+			"Location": {url},
+		})
+		if err != nil {
+			log.Err(err).Msg("Failed to create multipart redirect field")
+			return
+		}
+		err = mp.Close()
+		if err != nil {
+			log.Err(err).Msg("Failed to close multipart writer")
+			return
+		}
+		return
 	}
 	// Proxy if the config allows proxying and the request doesn't allow redirects.
 	// In any other case, redirect to the Discord CDN.