Add support for WebSocket Sub-Protocols

Sub-Protocol support follows RFC 6455 Sections 4.1 and 4.2. See also
https://datatracker.ietf.org/doc/html/rfc6455.

This patch introduces a new class QWebSocketHandshakeOptions which
collects options for the WebSocket handshake. At the moment, this
contains only accessors for sub-protocols. In the future, it can be
extended with things like WebSocket extensions.

[ChangeLog] Add support for WebSocket Sub-Protocols

Fixes: QTBUG-38742
Change-Id: Ibdcef17f717f0a76caab54f65c550865df1ec78d
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

3 files changed, 120 insertions, 1 deletions

diff --git a/tests/auto/qml/qmlwebsockets/tst_qmlwebsockets.qml b/tests/auto/qml/qmlwebsockets/tst_qmlwebsockets.qml
index 66c1ed0..21d3bf6 100644
--- a/tests/auto/qml/qmlwebsockets/tst_qmlwebsockets.qml
+++ b/tests/auto/qml/qmlwebsockets/tst_qmlwebsockets.qml
@@ -38,6 +38,8 @@ Rectangle {
         id: server
         port: 1337
 
+        supportedSubprotocols: [ "chat", "superchat" ]
+
         onClientConnected: {
             currentSocket = webSocket;
         }
@@ -48,6 +50,7 @@ Rectangle {
     WebSocket {
         id: socket
         url: server.url
+        requestedSubprotocols: [ "superchat", "chat" ]
     }
 
     TestCase {
@@ -56,6 +59,10 @@ Rectangle {
             socket.active = true;
             tryCompare(socket, 'status', WebSocket.Open);
             verify(server.currentSocket);
+
+            // Handshake should select client's first preference.
+            compare(socket.negotiatedSubprotocol, "superchat")
+            compare(server.currentSocket.negotiatedSubprotocol, "superchat")
         }
 
         function ensureDisconnected() {
diff --git a/tests/auto/websockets/qwebsocket/tst_qwebsocket.cpp b/tests/auto/websockets/qwebsocket/tst_qwebsocket.cpp
index 329419c..4f85430 100644
--- a/tests/auto/websockets/qwebsocket/tst_qwebsocket.cpp
+++ b/tests/auto/websockets/qwebsocket/tst_qwebsocket.cpp
@@ -25,9 +25,11 @@
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
+#include <QRegularExpression>
 #include <QString>
 #include <QtTest>
 #include <QtWebSockets/QWebSocket>
+#include <QtWebSockets/QWebSocketHandshakeOptions>
 #include <QtWebSockets/QWebSocketServer>
 #include <QtWebSockets/qwebsocketprotocol.h>
 
@@ -72,6 +74,8 @@ EchoServer::EchoServer(QObject *parent, quint64 maxAllowedIncomingMessageSize, q
     m_maxAllowedIncomingFrameSize(maxAllowedIncomingFrameSize),
     m_clients()
 {
+    m_pWebSocketServer->setSupportedSubprotocols({ QStringLiteral("protocol1"),
+                                                QStringLiteral("protocol2") });
     if (m_pWebSocketServer->listen(QHostAddress(QStringLiteral("127.0.0.1")))) {
         connect(m_pWebSocketServer, SIGNAL(newConnection()),
                 this, SLOT(onNewConnection()));
@@ -146,7 +150,9 @@ private Q_SLOTS:
     void tst_sendTextMessage();
     void tst_sendBinaryMessage();
     void tst_errorString();
+    void tst_openRequest_data();
     void tst_openRequest();
+    void tst_protocolAccessor();
     void tst_moveToThread();
     void tst_moveToThreadNoWarning();
 #ifndef QT_NO_NETWORKPROXY
@@ -631,8 +637,35 @@ void tst_QWebSocket::tst_errorString()
     QCOMPARE(socket.errorString(), QStringLiteral("Host not found"));
 }
 
+void tst_QWebSocket::tst_openRequest_data()
+{
+    QTest::addColumn<QStringList>("subprotocols");
+    QTest::addColumn<QString>("subprotocolHeader");
+    QTest::addColumn<QRegularExpression>("warningExpression");
+
+    QTest::addRow("no subprotocols") << QStringList{} << QString{} << QRegularExpression{};
+    QTest::addRow("single subprotocol") << QStringList{"foobar"} << QStringLiteral("foobar")
+                                        << QRegularExpression{};
+    QTest::addRow("multiple subprotocols") << QStringList{"foo", "bar"}
+                                           << QStringLiteral("foo, bar")
+                                           << QRegularExpression{};
+    QTest::addRow("subprotocol with whitespace")
+            << QStringList{"chat", "foo\r\nbar with space"}
+            << QStringLiteral("chat")
+            << QRegularExpression{".*invalid.*bar with space"};
+
+    QTest::addRow("subprotocol with invalid chars")
+            << QStringList{"chat", "foo{}"}
+            << QStringLiteral("chat")
+            << QRegularExpression{".*invalid.*foo"};
+}
+
 void tst_QWebSocket::tst_openRequest()
 {
+    QFETCH(QStringList, subprotocols);
+    QFETCH(QString, subprotocolHeader);
+    QFETCH(QRegularExpression, warningExpression);
+
     EchoServer echoServer;
 
     QWebSocket socket;
@@ -647,7 +680,13 @@ void tst_QWebSocket::tst_openRequest()
     url.setQuery(query);
     QNetworkRequest req(url);
     req.setRawHeader("X-Custom-Header", "A custom header");
-    socket.open(req);
+    QWebSocketHandshakeOptions options;
+    options.setSubprotocols(subprotocols);
+
+    if (!warningExpression.pattern().isEmpty())
+        QTest::ignoreMessage(QtWarningMsg, warningExpression);
+
+    socket.open(req, options);
 
     QTRY_COMPARE(socketConnectedSpy.count(), 1);
     QTRY_COMPARE(serverRequestSpy.count(), 1);
@@ -656,6 +695,34 @@ void tst_QWebSocket::tst_openRequest()
     QNetworkRequest requestConnected = arguments.at(0).value<QNetworkRequest>();
     QCOMPARE(requestConnected.url(), req.url());
     QCOMPARE(requestConnected.rawHeader("X-Custom-Header"), req.rawHeader("X-Custom-Header"));
+
+    if (subprotocols.isEmpty())
+        QVERIFY(!requestConnected.hasRawHeader("Sec-WebSocket-Protocol"));
+    else
+        QCOMPARE(requestConnected.rawHeader("Sec-WebSocket-Protocol"), subprotocolHeader);
+
+
+    socket.close();
+}
+
+void tst_QWebSocket::tst_protocolAccessor()
+{
+    EchoServer echoServer;
+
+    QWebSocket socket;
+
+    QUrl url = QUrl(QStringLiteral("ws://") + echoServer.hostAddress().toString() +
+                    QLatin1Char(':') + QString::number(echoServer.port()));
+
+    QWebSocketHandshakeOptions options;
+    options.setSubprotocols({ "foo", "protocol2" });
+
+    socket.open(url, options);
+
+    QTRY_COMPARE(socket.state(), QAbstractSocket::ConnectedState);
+
+    QCOMPARE(socket.subprotocol(), "protocol2");
+
     socket.close();
 }
 
diff --git a/tests/auto/websockets/qwebsocketserver/tst_qwebsocketserver.cpp b/tests/auto/websockets/qwebsocketserver/tst_qwebsocketserver.cpp
index b2dd95f..c25e864 100644
--- a/tests/auto/websockets/qwebsocketserver/tst_qwebsocketserver.cpp
+++ b/tests/auto/websockets/qwebsocketserver/tst_qwebsocketserver.cpp
@@ -37,6 +37,7 @@
 #include <QtNetwork/qsslkey.h>
 #include <QtNetwork/qsslsocket.h>
 #endif
+#include <QtWebSockets/QWebSocketHandshakeOptions>
 #include <QtWebSockets/QWebSocketServer>
 #include <QtWebSockets/QWebSocket>
 #include <QtWebSockets/QWebSocketCorsAuthenticator>
@@ -106,6 +107,8 @@ private Q_SLOTS:
     void tst_settersAndGetters();
     void tst_listening();
     void tst_connectivity();
+    void tst_protocols_data();
+    void tst_protocols();
     void tst_preSharedKey();
     void tst_maxPendingConnections();
     void tst_serverDestroyedWhileSocketConnected();
@@ -375,6 +378,48 @@ void tst_QWebSocketServer::tst_connectivity()
     QCOMPARE(serverErrorSpy.count(), 0);
 }
 
+void tst_QWebSocketServer::tst_protocols_data()
+{
+    QTest::addColumn<QStringList>("clientProtocols");
+    QTest::addColumn<QString>("expectedProtocol");
+    QTest::addRow("none") << QStringList {} << QString {};
+    QTest::addRow("same order as server")
+            << QStringList { "chat", "superchat" } << QStringLiteral("chat");
+    QTest::addRow("different order from server")
+            << QStringList { "superchat", "chat" } << QStringLiteral("superchat");
+    QTest::addRow("unsupported protocol") << QStringList { "foo" } << QString {};
+    QTest::addRow("mixed supported/unsupported protocol")
+            << QStringList { "foo", "chat" } << QStringLiteral("chat");
+}
+
+void tst_QWebSocketServer::tst_protocols()
+{
+    QFETCH(QStringList, clientProtocols);
+    QFETCH(QString, expectedProtocol);
+
+    QWebSocketServer server(QString(), QWebSocketServer::NonSecureMode);
+    server.setSupportedSubprotocols({ QStringLiteral("chat"), QStringLiteral("superchat") });
+
+    QSignalSpy newConnectionSpy(&server, &QWebSocketServer::newConnection);
+
+    QVERIFY(server.listen());
+
+    QWebSocketHandshakeOptions opt;
+    opt.setSubprotocols(clientProtocols);
+    QWebSocket client;
+    client.open(server.serverUrl(), opt);
+
+    QTRY_COMPARE(client.state(), QAbstractSocket::ConnectedState);
+    QTRY_COMPARE(newConnectionSpy.count(), 1);
+
+    auto *serverSocket = server.nextPendingConnection();
+    QVERIFY(serverSocket);
+
+    QCOMPARE(client.subprotocol(), expectedProtocol);
+    QCOMPARE(serverSocket->subprotocol(), expectedProtocol);
+    QCOMPARE(serverSocket->handshakeOptions().subprotocols(), clientProtocols);
+}
+
 void tst_QWebSocketServer::tst_preSharedKey()
 {
     if (m_shouldSkipUnsupportedIpv6Test)