Allow file access apis to respond to HEAD requests

api/file.go

@@ -33,7 +33,7 @@ func InitFile(r *mux.Router) {
 
 	sr := r.PathPrefix("/files").Subrouter()
 	sr.Handle("/upload", ApiUserRequired(uploadFile)).Methods("POST")
-	sr.Handle("/get/{channel_id:[A-Za-z0-9]+}/{user_id:[A-Za-z0-9]+}/{filename:([A-Za-z0-9]+/)?.+(\\.[A-Za-z0-9]{3,})?}", ApiAppHandler(getFile)).Methods("GET")
+	sr.Handle("/get/{channel_id:[A-Za-z0-9]+}/{user_id:[A-Za-z0-9]+}/{filename:([A-Za-z0-9]+/)?.+(\\.[A-Za-z0-9]{3,})?}", ApiAppHandler(getFile)).Methods("GET", "HEAD")
 	sr.Handle("/get_public_link", ApiUserRequired(getPublicLink)).Methods("POST")
 }