net/http: add Server.OptionsHandler for custom handling of OPTIONS *

src/net/http/serve_test.go

@@ -3434,6 +3434,42 @@ func TestOptions(t *testing.T) {
 	}
 }
 
+func TestOptionsHandler(t *testing.T) {
+	rc := make(chan *Request, 1)
+
+	ts := httptest.NewUnstartedServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+		t.Fatalf("Got unexpected request %v", r)
+	}))
+	ts.Config.OptionsHandler = HandlerFunc(func(w ResponseWriter, r *Request) {
+		w.Header().Set("Content-Length", "0")
+		rc <- r
+	})
+	ts.Start()
+	defer ts.Close()
+
+	conn, err := net.Dial("tcp", ts.Listener.Addr().String())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer conn.Close()
+
+	_, err = conn.Write([]byte("OPTIONS * HTTP/1.1\r\nHost: foo.com\r\n\r\n"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	res, err := ReadResponse(bufio.NewReader(conn), &Request{Method: "OPTIONS"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if res.StatusCode != 200 {
+		t.Errorf("Got non-200 response to OPTIONS *: %#v", res)
+	}
+
+	if got := <-rc; got.Method != "OPTIONS" || got.RequestURI != "*" {
+		t.Errorf("Expected OPTIONS * request, got %v", got)
+	}
+}
+
 // Tests regarding the ordering of Write, WriteHeader, Header, and
 // Flush calls. In Go 1.0, rw.WriteHeader immediately flushed the
 // (*response).header to the wire. In Go 1.1, the actual wire flush is

src/net/http/server.go

@@ -2570,6 +2570,10 @@ type Server struct {
 
 	Handler Handler // handler to invoke, http.DefaultServeMux if nil
 
+	// OptionsHandler handles "OPTIONS *" requests.
+	// If nil, server responds with 200 OK and Content-Length: 0.
+	OptionsHandler Handler
+
 	// TLSConfig optionally provides a TLS configuration for use
 	// by ServeTLS and ListenAndServeTLS. Note that this value is
 	// cloned by ServeTLS and ListenAndServeTLS, so it's not
@@ -2897,7 +2901,10 @@ func (sh serverHandler) ServeHTTP(rw ResponseWriter, req *Request) {
 		handler = DefaultServeMux
 	}
 	if req.RequestURI == "*" && req.Method == "OPTIONS" {
-		handler = globalOptionsHandler{}
+		handler = sh.srv.OptionsHandler
+		if handler == nil {
+			handler = globalOptionsHandler{}
+		}
 	}
 
 	if req.URL != nil && strings.Contains(req.URL.RawQuery, ";") {