diff --git a/README.md b/README.md
index a1b2e2b..c422070 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,8 @@
+# GOPROXY
 
-# GOPROXY [![CircleCI](https://circleci.com/gh/goproxyio/goproxy.svg?style=svg)](https://circleci.com/gh/goproxyio/goproxy)
+[![CircleCI](https://circleci.com/gh/goproxyio/goproxy.svg?style=svg)](https://circleci.com/gh/goproxyio/goproxy)
+[![Go Report Card](https://goreportcard.com/badge/github.com/goproxyio/goproxy)](https://goreportcard.com/report/github.com/goproxyio/goproxy)
+[![GoDoc](https://godoc.org/github.com/goproxyio/goproxy?status.svg)](https://godoc.org/github.com/goproxyio/goproxy)
 
 A global proxy for go modules. see: [https://goproxy.io](https://goproxy.io)
 
diff --git a/proxy/router.go b/proxy/router.go
index c5d0caa..fe24361 100644
--- a/proxy/router.go
+++ b/proxy/router.go
@@ -19,9 +19,10 @@ import (
 	"github.com/goproxyio/goproxy/v2/sumdb"
 )
 
+// ListExpire list data expire data duration.
 const ListExpire = 5 * time.Minute
 
-// A RouterOps provides the proxy host and the external pattern
+// RouterOptions provides the proxy host and the external pattern
 type RouterOptions struct {
 	Pattern      string
 	Proxy        string
@@ -103,6 +104,7 @@ func NewRouter(srv *Server, opts *RouterOptions) *Router {
 	return rt
 }
 
+// Direct decides whether a path should directly access.
 func (rt *Router) Direct(path string) bool {
 	if rt.pattern == "" {
 		return false
@@ -153,9 +155,8 @@ func (rt *Router) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 					log.Printf("------ --- %s [proxy]\n", r.URL)
 					rt.proxy.ServeHTTP(w, r)
 					return
-				} else {
-					ctype = "text/plain; charset=UTF-8"
 				}
+				ctype = "text/plain; charset=UTF-8"
 			} else {
 				ext := path.Ext(what)
 				switch ext {
diff --git a/proxy/server.go b/proxy/server.go
index 8c7c3e2..c3bbbd3 100644
--- a/proxy/server.go
+++ b/proxy/server.go
@@ -1,6 +1,7 @@
 // Copyright 2019 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
+
 // Package proxy implements the HTTP protocols for serving a Go module proxy.
 package proxy
 
diff --git a/sumdb/handler.go b/sumdb/handler.go
index 9695b00..0378466 100644
--- a/sumdb/handler.go
+++ b/sumdb/handler.go
@@ -1,7 +1,8 @@
 // Copyright 2019 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
-// Package proxy implements the HTTP protocols for serving a Go module proxy.
+
+// Package sumdb implements sumdb handler proxy.
 package sumdb
 
 import (