Add Subprotocols helper function.

server.go

@@ -9,6 +9,7 @@ import (
 	"errors"
 	"net"
 	"net/http"
+	"strings"
 )
 
 // HandshakeError describes an error with the handshake from the peer.
@@ -104,3 +105,17 @@ func Upgrade(w http.ResponseWriter, r *http.Request, responseHeader http.Header,
 
 	return c, nil
 }
+
+// Subprotocols returns the subprotocols requested by the client in the
+// Sec-Websocket-Protocol header.
+func Subprotocols(r *http.Request) []string {
+	h := strings.TrimSpace(r.Header.Get("Sec-Websocket-Protocol"))
+	if h == "" {
+		return nil
+	}
+	protocols := strings.Split(h, ",")
+	for i := range protocols {
+		protocols[i] = strings.TrimSpace(protocols[i])
+	}
+	return protocols
+}

server_test.go

@@ -0,0 +1,33 @@
+// Copyright 2013 Gary Burd. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package websocket
+
+import (
+	"net/http"
+	"reflect"
+	"testing"
+)
+
+var subprotocolTests = []struct {
+	h         string
+	protocols []string
+}{
+	{"", nil},
+	{"foo", []string{"foo"}},
+	{"foo,bar", []string{"foo", "bar"}},
+	{"foo, bar", []string{"foo", "bar"}},
+	{" foo, bar", []string{"foo", "bar"}},
+	{" foo, bar ", []string{"foo", "bar"}},
+}
+
+func TestSubprotocols(t *testing.T) {
+	for _, st := range subprotocolTests {
+		r := http.Request{Header: http.Header{"Sec-Websocket-Protocol": {st.h}}}
+		protocols := Subprotocols(&r)
+		if !reflect.DeepEqual(st.protocols, protocols) {
+			t.Errorf("SubProtocols(%q) returned %#v, want %#v", st.h, protocols, st.protocols)
+		}
+	}
+}