Transports need to handle open/close stanzas

XMPP and WebSocket transports require different open and close stanzas. To
handle this the responsibility handling those and creating the XML decoder is
moved to the Transport.

websocket_transport.go

@@ -2,11 +2,15 @@ package xmpp
 
 import (
 	"context"
+	"encoding/xml"
 	"errors"
+	"fmt"
+	"io"
 	"net"
 	"strings"
 	"time"
 
+	"gosrc.io/xmpp/stanza"
 	"nhooyr.io/websocket"
 )
 
@@ -16,35 +20,60 @@ var ServerDoesNotSupportXmppOverWebsocket = errors.New("The websocket server doe
 
 type WebsocketTransport struct {
 	Config  TransportConfiguration
+	decoder *xml.Decoder
 	wsConn  *websocket.Conn
 	netConn net.Conn
-	ctx     context.Context
+	logFile io.Writer
 }
 
-func (t *WebsocketTransport) Connect() error {
-	t.ctx = context.Background()
+func (t *WebsocketTransport) Connect() (string, error) {
+	ctx := context.Background()
 
 	if t.Config.ConnectTimeout > 0 {
-		ctx, cancel := context.WithTimeout(t.ctx, time.Duration(t.Config.ConnectTimeout)*time.Second)
-		t.ctx = ctx
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, time.Duration(t.Config.ConnectTimeout)*time.Second)
 		defer cancel()
 	}
 
-	wsConn, response, err := websocket.Dial(t.ctx, t.Config.Address, &websocket.DialOptions{
+	wsConn, response, err := websocket.Dial(ctx, t.Config.Address, &websocket.DialOptions{
 		Subprotocols: []string{"xmpp"},
 	})
 	if err != nil {
-		return NewConnError(err, true)
+		return "", NewConnError(err, true)
 	}
 	if response.Header.Get("Sec-WebSocket-Protocol") != "xmpp" {
-		return ServerDoesNotSupportXmppOverWebsocket
+		_ = wsConn.Close(websocket.StatusBadGateway, "Could not negotiate XMPP subprotocol")
+		return "", NewConnError(ServerDoesNotSupportXmppOverWebsocket, true)
 	}
+
 	t.wsConn = wsConn
-	t.netConn = websocket.NetConn(t.ctx, t.wsConn, websocket.MessageText)
-	return nil
+	t.netConn = websocket.NetConn(ctx, t.wsConn, websocket.MessageText)
+
+	handshake := fmt.Sprintf("<open xmlns=\"urn:ietf:params:xml:ns:xmpp-framing\" to=\"%s\" version=\"1.0\" />", t.Config.Domain)
+	if _, err = t.Write([]byte(handshake)); err != nil {
+		_ = wsConn.Close(websocket.StatusBadGateway, "XMPP handshake error")
+		return "", NewConnError(err, false)
+	}
+
+	handshakeResponse := make([]byte, 2048)
+	if _, err = t.Read(handshakeResponse); err != nil {
+		_ = wsConn.Close(websocket.StatusBadGateway, "XMPP handshake error")
+		return "", NewConnError(err, false)
+	}
+
+	var openResponse = stanza.WebsocketOpen{}
+	if err = xml.Unmarshal(handshakeResponse, &openResponse); err != nil {
+		_ = wsConn.Close(websocket.StatusBadGateway, "XMPP handshake error")
+		return "", NewConnError(err, false)
+	}
+
+	t.decoder = xml.NewDecoder(t)
+	t.decoder.CharsetReader = t.Config.CharsetReader
+
+	return openResponse.Id, nil
 }
 
-func (t WebsocketTransport) StartTLS(domain string) error {
+func (t WebsocketTransport) StartTLS() error {
 	return TLSNotSupported
 }
 
@@ -52,6 +81,10 @@ func (t WebsocketTransport) DoesStartTLS() bool {
 	return false
 }
 
+func (t WebsocketTransport) GetDecoder() *xml.Decoder {
+	return t.decoder
+}
+
 func (t WebsocketTransport) IsSecure() bool {
 	return strings.HasPrefix(t.Config.Address, "wss:")
 }
@@ -59,19 +92,29 @@ func (t WebsocketTransport) IsSecure() bool {
 func (t WebsocketTransport) Ping() error {
 	ctx, cancel := context.WithTimeout(context.Background(), pingTimeout)
 	defer cancel()
-	// Note that we do not use wsConn.Ping(), because not all websocket servers
-	// (ejabberd for example) implement ping frames
-	return t.wsConn.Write(ctx, websocket.MessageText, []byte(" "))
+	return t.wsConn.Ping(ctx)
 }
 
-func (t WebsocketTransport) Read(p []byte) (n int, err error) {
-	return t.netConn.Read(p)
+func (t *WebsocketTransport) Read(p []byte) (n int, err error) {
+	n, err = t.netConn.Read(p)
+	if t.logFile != nil && n > 0 {
+		_, _ = fmt.Fprintf(t.logFile, "RECV:\n%s\n\n", p)
+	}
+	return
 }
 
 func (t WebsocketTransport) Write(p []byte) (n int, err error) {
+	if t.logFile != nil {
+		_, _ = fmt.Fprintf(t.logFile, "SEND:\n%s\n\n", p)
+	}
 	return t.netConn.Write(p)
 }
 
 func (t WebsocketTransport) Close() error {
+	t.Write([]byte("<close xmlns=\"urn:ietf:params:xml:ns:xmpp-framing\" />"))
 	return t.netConn.Close()
 }
+
+func (t *WebsocketTransport) LogTraffic(logFile io.Writer) {
+	t.logFile = logFile
+}