Add support filename query param for mp4 files

internal/mp4/mp4.go

@@ -38,7 +38,8 @@ func handlerKeyframe(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	src := r.URL.Query().Get("src")
+	query := r.URL.Query()
+	src := query.Get("src")
 	stream := streams.GetOrNew(src)
 	if stream == nil {
 		http.Error(w, api.StreamNotFound, http.StatusNotFound)
@@ -69,8 +70,13 @@ func handlerKeyframe(w http.ResponseWriter, r *http.Request) {
 	stream.RemoveConsumer(cons)
 
 	// Apple Safari won't show frame without length
-	w.Header().Set("Content-Length", strconv.Itoa(len(data)))
+	header := w.Header()
-	w.Header().Set("Content-Type", cons.MimeType)
+	header.Set("Content-Length", strconv.Itoa(len(data)))
+	header.Set("Content-Type", cons.MimeType)
+
+	if filename := query.Get("filename"); filename != "" {
+		header.Set("Content-Disposition", `attachment; filename="`+filename+`"`)
+	}
 
 	if _, err := w.Write(data); err != nil {
 		log.Error().Err(err).Caller().Send()
@@ -132,8 +138,6 @@ func handlerMP4(w http.ResponseWriter, r *http.Request) {
 
 	defer stream.RemoveConsumer(cons)
 
-	w.Header().Set("Content-Type", cons.MimeType())
-
 	data, err := cons.Init()
 	if err != nil {
 		log.Error().Err(err).Caller().Send()
@@ -141,6 +145,13 @@ func handlerMP4(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	header := w.Header()
+	header.Set("Content-Type", cons.MimeType())
+
+	if filename := query.Get("filename"); filename != "" {
+		header.Set("Content-Disposition", `attachment; filename="`+filename+`"`)
+	}
+
 	if _, err = w.Write(data); err != nil {
 		log.Error().Err(err).Caller().Send()
 		http.Error(w, err.Error(), http.StatusInternalServerError)