From 725519902f005260f55c6248fdc70d890d754fdb Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@golang.org>
Date: Mon, 18 Mar 2013 13:44:20 -0700
Subject: [PATCH] net/http: add StripPrefix example; simplify code

The example is the same as the FileServer one, but
it's relevant for both.

Also use strings.TrimPrefix while I'm here.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7598046
---
 src/pkg/net/http/example_test.go |  5 +++++
 src/pkg/net/http/server.go       | 11 +++++++----
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/pkg/net/http/example_test.go b/src/pkg/net/http/example_test.go
index 22073eaf7a..eed3beeea3 100644
--- a/src/pkg/net/http/example_test.go
+++ b/src/pkg/net/http/example_test.go
@@ -54,3 +54,8 @@ func ExampleFileServer() {
 	// we use StripPrefix so that /tmpfiles/somefile will access /tmp/somefile
 	http.Handle("/tmpfiles/", http.StripPrefix("/tmpfiles/", http.FileServer(http.Dir("/tmp"))))
 }
+
+func ExampleStripPrefix() {
+	// we use StripPrefix so that /tmpfiles/somefile will access /tmp/somefile
+	http.Handle("/tmpfiles/", http.StripPrefix("/tmpfiles/", http.FileServer(http.Dir("/tmp"))))
+}
diff --git a/src/pkg/net/http/server.go b/src/pkg/net/http/server.go
index 9021767163..5086ad0a79 100644
--- a/src/pkg/net/http/server.go
+++ b/src/pkg/net/http/server.go
@@ -948,13 +948,16 @@ func NotFoundHandler() Handler { return HandlerFunc(NotFound) }
 // request for a path that doesn't begin with prefix by
 // replying with an HTTP 404 not found error.
 func StripPrefix(prefix string, h Handler) Handler {
+	if prefix == "" {
+		return h
+	}
 	return HandlerFunc(func(w ResponseWriter, r *Request) {
-		if !strings.HasPrefix(r.URL.Path, prefix) {
+		if p := strings.TrimPrefix(r.URL.Path, prefix); len(p) < len(r.URL.Path) {
+			r.URL.Path = p
+			h.ServeHTTP(w, r)
+		} else {
 			NotFound(w, r)
-			return
 		}
-		r.URL.Path = r.URL.Path[len(prefix):]
-		h.ServeHTTP(w, r)
 	})
 }
 
-- 
2.50.0