add mux config

handler/file/metadata.go

@@ -0,0 +1,15 @@
+package file
+
+import (
+	mdata "github.com/go-gost/core/metadata"
+	mdutil "github.com/go-gost/core/metadata/util"
+)
+
+type metadata struct {
+	dir string
+}
+
+func (h *fileHandler) parseMetadata(md mdata.Metadata) (err error) {
+	h.md.dir = mdutil.GetString(md, "file.dir", "dir")
+	return
+}