Add the webchannel standalone example

Task-number: PYSIDE-1199
Change-Id: Icc138844b0cb5e7ccb502cbe840fc578fad8ca8f
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

9 files changed, 575 insertions, 0 deletions

diff --git a/examples/webchannel/standalone/core.py b/examples/webchannel/standalone/core.py
new file mode 100644
index 000000000..9fb056496
--- /dev/null
+++ b/examples/webchannel/standalone/core.py
@@ -0,0 +1,62 @@
+#############################################################################
+##
+## Copyright (C) 2017 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Milian Wolff <milian.wolff@kdab.com>
+## Copyright (C) 2020 The Qt Company Ltd.
+## Contact: http://www.qt.io/licensing/
+##
+## This file is part of the Qt for Python examples of the Qt Toolkit.
+##
+## $QT_BEGIN_LICENSE:BSD$
+## You may use this file under the terms of the BSD license as follows:
+##
+## "Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions are
+## met:
+##   * Redistributions of source code must retain the above copyright
+##     notice, this list of conditions and the following disclaimer.
+##   * Redistributions in binary form must reproduce the above copyright
+##     notice, this list of conditions and the following disclaimer in
+##     the documentation and/or other materials provided with the
+##     distribution.
+##   * Neither the name of The Qt Company Ltd nor the names of its
+##     contributors may be used to endorse or promote products derived
+##     from this software without specific prior written permission.
+##
+##
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+
+from PySide2.QtCore import QObject, Signal, Slot
+
+
+class Core(QObject):
+    """An instance of this class gets published over the WebChannel and is then
+       accessible to HTML clients."""
+    sendText = Signal(str)
+
+    def __init__(self, dialog, parent=None):
+        super(Core, self).__init__(parent)
+        self._dialog = dialog
+        self._dialog.sendText.connect(self._emit_send_text)
+
+    @Slot(str)
+    def _emit_send_text(self, text):
+        self.sendText.emit(text)
+
+    @Slot(str)
+    def receiveText(self, text):
+        self._dialog.displayMessage("Received message: {}".format(text))
diff --git a/examples/webchannel/standalone/dialog.py b/examples/webchannel/standalone/dialog.py
new file mode 100644
index 000000000..45951deb9
--- /dev/null
+++ b/examples/webchannel/standalone/dialog.py
@@ -0,0 +1,68 @@
+#############################################################################
+##
+## Copyright (C) 2017 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Milian Wolff <milian.wolff@kdab.com>
+## Copyright (C) 2020 The Qt Company Ltd.
+## Contact: http://www.qt.io/licensing/
+##
+## This file is part of the Qt for Python examples of the Qt Toolkit.
+##
+## $QT_BEGIN_LICENSE:BSD$
+## You may use this file under the terms of the BSD license as follows:
+##
+## "Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions are
+## met:
+##   * Redistributions of source code must retain the above copyright
+##     notice, this list of conditions and the following disclaimer.
+##   * Redistributions in binary form must reproduce the above copyright
+##     notice, this list of conditions and the following disclaimer in
+##     the documentation and/or other materials provided with the
+##     distribution.
+##   * Neither the name of The Qt Company Ltd nor the names of its
+##     contributors may be used to endorse or promote products derived
+##     from this software without specific prior written permission.
+##
+##
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+
+from PySide2.QtCore import Signal, Slot
+from PySide2.QtWidgets import QDialog
+from ui_dialog import Ui_Dialog
+
+
+class Dialog(QDialog):
+    sendText = Signal(str)
+
+    def __init__(self, parent=None):
+        super(Dialog, self).__init__(parent)
+        self._ui = Ui_Dialog()
+        self._ui.setupUi(self)
+        self._ui.send.clicked.connect(self.clicked)
+
+    @Slot(str)
+    def displayMessage(self, message):
+        self._ui.output.appendPlainText(message)
+
+    @Slot()
+    def clicked(self):
+        text = self._ui.input.text()
+        if not text:
+            return
+        self.sendText.emit(text)
+        self.displayMessage("Sent message: {}".format(text))
+        self._ui.input.clear()
diff --git a/examples/webchannel/standalone/dialog.ui b/examples/webchannel/standalone/dialog.ui
new file mode 100644
index 000000000..056a3f587
--- /dev/null
+++ b/examples/webchannel/standalone/dialog.ui
@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>Dialog</class>
+ <widget class="QDialog" name="Dialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>400</width>
+    <height>300</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Dialog</string>
+  </property>
+  <layout class="QGridLayout" name="gridLayout">
+   <item row="1" column="0">
+    <widget class="QLineEdit" name="input">
+     <property name="placeholderText">
+      <string>Message Contents</string>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="1">
+    <widget class="QPushButton" name="send">
+     <property name="text">
+      <string>Send</string>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="0" colspan="2">
+    <widget class="QPlainTextEdit" name="output">
+     <property name="readOnly">
+      <bool>true</bool>
+     </property>
+     <property name="plainText">
+      <string notr="true">Initializing WebChannel...</string>
+     </property>
+     <property name="backgroundVisible">
+      <bool>false</bool>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>
diff --git a/examples/webchannel/standalone/index.html b/examples/webchannel/standalone/index.html
new file mode 100644
index 000000000..7c042cd0c
--- /dev/null
+++ b/examples/webchannel/standalone/index.html
@@ -0,0 +1,79 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+        <script type="text/javascript" src="./qwebchannel.js"></script>
+        <script type="text/javascript">
+            //BEGIN SETUP
+            function output(message) {
+                var output = document.getElementById("output");
+                output.innerHTML = output.innerHTML + message + "\n";
+            }
+            window.onload = function() {
+                if (location.search != "")
+                    var baseUrl = (/[?&]webChannelBaseUrl=([A-Za-z0-9\-:/\.]+)/.exec(location.search)[1]);
+                else
+                    var baseUrl = "ws://localhost:12345";
+
+                output("Connecting to WebSocket server at " + baseUrl + ".");
+                var socket = new WebSocket(baseUrl);
+
+                socket.onclose = function() {
+                    console.error("web channel closed");
+                };
+                socket.onerror = function(error) {
+                    console.error("web channel error: " + error);
+                };
+                socket.onopen = function() {
+                    output("WebSocket connected, setting up QWebChannel.");
+                    new QWebChannel(socket, function(channel) {
+                        // make core object accessible globally
+                        window.core = channel.objects.core;
+
+                        document.getElementById("send").onclick = function() {
+                            var input = document.getElementById("input");
+                            var text = input.value;
+                            if (!text) {
+                                return;
+                            }
+
+                            output("Sent message: " + text);
+                            input.value = "";
+                            core.receiveText(text);
+                        }
+
+                        core.sendText.connect(function(message) {
+                            output("Received message: " + message);
+                        });
+
+                        core.receiveText("Client connected, ready to send/receive messages!");
+                        output("Connected to WebChannel, ready to send/receive messages!");
+                    });
+                }
+            }
+            //END SETUP
+        </script>
+        <style type="text/css">
+            html {
+                height: 100%;
+                width: 100%;
+            }
+            #input {
+                width: 400px;
+                margin: 0 10px 0 0;
+            }
+            #send {
+                width: 90px;
+                margin: 0;
+            }
+            #output {
+                width: 500px;
+                height: 300px;
+            }
+        </style>
+    </head>
+    <body>
+        <textarea id="output"></textarea><br />
+        <input id="input" /><input type="submit" id="send" value="Send" onclick="javascript:click();" />
+    </body>
+</html>
diff --git a/examples/webchannel/standalone/main.py b/examples/webchannel/standalone/main.py
new file mode 100644
index 000000000..d3119141f
--- /dev/null
+++ b/examples/webchannel/standalone/main.py
@@ -0,0 +1,99 @@
+#############################################################################
+##
+## Copyright (C) 2016 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Milian Wolff <milian.wolff@kdab.com>
+## Copyright (C) 2020 The Qt Company Ltd.
+## Contact: http://www.qt.io/licensing/
+##
+## This file is part of the Qt for Python examples of the Qt Toolkit.
+##
+## $QT_BEGIN_LICENSE:BSD$
+## You may use this file under the terms of the BSD license as follows:
+##
+## "Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions are
+## met:
+##   * Redistributions of source code must retain the above copyright
+##     notice, this list of conditions and the following disclaimer.
+##   * Redistributions in binary form must reproduce the above copyright
+##     notice, this list of conditions and the following disclaimer in
+##     the documentation and/or other materials provided with the
+##     distribution.
+##   * Neither the name of The Qt Company Ltd nor the names of its
+##     contributors may be used to endorse or promote products derived
+##     from this software without specific prior written permission.
+##
+##
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+
+import os
+import sys
+
+from PySide2.QtWidgets import QApplication
+from PySide2.QtGui import QDesktopServices
+from PySide2.QtNetwork import QHostAddress, QSslSocket
+from PySide2.QtCore import (QFile, QFileInfo, QUrl)
+from PySide2.QtWebChannel import QWebChannel
+from PySide2.QtWebSockets import QWebSocketServer
+
+from dialog import Dialog
+from core import Core
+from websocketclientwrapper import WebSocketClientWrapper
+
+
+if __name__ == '__main__':
+    app = QApplication(sys.argv)
+    if not QSslSocket.supportsSsl():
+        print('The example requires SSL support.')
+        sys.exit(-1)
+    cur_dir = os.path.dirname(os.path.abspath(__file__))
+    jsFileInfo = QFileInfo(cur_dir + "/qwebchannel.js")
+    if not jsFileInfo.exists():
+        QFile.copy(":/qtwebchannel/qwebchannel.js",
+                   jsFileInfo.absoluteFilePath())
+
+    # setup the QWebSocketServer
+    server = QWebSocketServer("QWebChannel Standalone Example Server",
+                              QWebSocketServer.NonSecureMode)
+    if not server.listen(QHostAddress.LocalHost, 12345):
+        print("Failed to open web socket server.")
+        sys.exit(-1)
+
+    # wrap WebSocket clients in QWebChannelAbstractTransport objects
+    clientWrapper = WebSocketClientWrapper(server)
+
+    # setup the channel
+    channel = QWebChannel()
+    clientWrapper.clientConnected.connect(channel.connectTo)
+
+    # setup the UI
+    dialog = Dialog()
+
+    # setup the core and publish it to the QWebChannel
+    core = Core(dialog)
+    channel.registerObject("core", core)
+
+    # open a browser window with the client HTML page
+    url = QUrl.fromLocalFile(cur_dir + "/index.html")
+    QDesktopServices.openUrl(url)
+
+    message = "Initialization complete, opening browser at {}.".format(
+              url.toDisplayString())
+    dialog.displayMessage(message)
+    dialog.show()
+
+    sys.exit(app.exec_())
diff --git a/examples/webchannel/standalone/standalone.pyproject b/examples/webchannel/standalone/standalone.pyproject
new file mode 100644
index 000000000..b4fcdfa8e
--- /dev/null
+++ b/examples/webchannel/standalone/standalone.pyproject
@@ -0,0 +1,4 @@
+{
+    "files": ["main.py", "core.py", "dialog.py", "websocketclientwrapper.py",
+              "websockettransport.py", "dialog.ui", "index.html"]
+}
diff --git a/examples/webchannel/standalone/ui_dialog.py b/examples/webchannel/standalone/ui_dialog.py
new file mode 100644
index 000000000..873edba10
--- /dev/null
+++ b/examples/webchannel/standalone/ui_dialog.py
@@ -0,0 +1,55 @@
+# -*- coding: utf-8 -*-
+
+################################################################################
+## Form generated from reading UI file 'dialog.ui'
+##
+## Created by: Qt User Interface Compiler version 5.14.1
+##
+## WARNING! All changes made in this file will be lost when recompiling UI file!
+################################################################################
+
+from PySide2.QtCore import (QCoreApplication, QMetaObject, QObject, QPoint,
+    QRect, QSize, QUrl, Qt)
+from PySide2.QtGui import (QBrush, QColor, QConicalGradient, QCursor, QFont,
+    QFontDatabase, QIcon, QLinearGradient, QPalette, QPainter, QPixmap,
+    QRadialGradient)
+from PySide2.QtWidgets import *
+
+
+class Ui_Dialog(object):
+    def setupUi(self, Dialog):
+        if not Dialog.objectName():
+            Dialog.setObjectName(u"Dialog")
+        Dialog.resize(400, 300)
+        self.gridLayout = QGridLayout(Dialog)
+        self.gridLayout.setObjectName(u"gridLayout")
+        self.input = QLineEdit(Dialog)
+        self.input.setObjectName(u"input")
+
+        self.gridLayout.addWidget(self.input, 1, 0, 1, 1)
+
+        self.send = QPushButton(Dialog)
+        self.send.setObjectName(u"send")
+
+        self.gridLayout.addWidget(self.send, 1, 1, 1, 1)
+
+        self.output = QPlainTextEdit(Dialog)
+        self.output.setObjectName(u"output")
+        self.output.setReadOnly(True)
+        self.output.setPlainText(u"Initializing WebChannel...")
+        self.output.setBackgroundVisible(False)
+
+        self.gridLayout.addWidget(self.output, 0, 0, 1, 2)
+
+
+        self.retranslateUi(Dialog)
+
+        QMetaObject.connectSlotsByName(Dialog)
+    # setupUi
+
+    def retranslateUi(self, Dialog):
+        Dialog.setWindowTitle(QCoreApplication.translate("Dialog", u"Dialog", None))
+        self.input.setPlaceholderText(QCoreApplication.translate("Dialog", u"Message Contents", None))
+        self.send.setText(QCoreApplication.translate("Dialog", u"Send", None))
+    # retranslateUi
+
diff --git a/examples/webchannel/standalone/websocketclientwrapper.py b/examples/webchannel/standalone/websocketclientwrapper.py
new file mode 100644
index 000000000..24505b03b
--- /dev/null
+++ b/examples/webchannel/standalone/websocketclientwrapper.py
@@ -0,0 +1,72 @@
+#############################################################################
+##
+## Copyright (C) 2017 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Milian Wolff <milian.wolff@kdab.com>
+## Copyright (C) 2020 The Qt Company Ltd.
+## Contact: http://www.qt.io/licensing/
+##
+## This file is part of the Qt for Python examples of the Qt Toolkit.
+##
+## $QT_BEGIN_LICENSE:BSD$
+## You may use this file under the terms of the BSD license as follows:
+##
+## "Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions are
+## met:
+##   * Redistributions of source code must retain the above copyright
+##     notice, this list of conditions and the following disclaimer.
+##   * Redistributions in binary form must reproduce the above copyright
+##     notice, this list of conditions and the following disclaimer in
+##     the documentation and/or other materials provided with the
+##     distribution.
+##   * Neither the name of The Qt Company Ltd nor the names of its
+##     contributors may be used to endorse or promote products derived
+##     from this software without specific prior written permission.
+##
+##
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+from PySide2.QtCore import QObject, Signal, Slot
+
+from websockettransport import WebSocketTransport
+
+
+class WebSocketClientWrapper(QObject):
+    """Wraps connected QWebSockets clients in WebSocketTransport objects.
+
+       This code is all that is required to connect incoming WebSockets to
+       the WebChannel. Any kind of remote JavaScript client that supports
+       WebSockets can thus receive messages and access the published objects.
+    """
+    clientConnected = Signal(WebSocketTransport)
+
+    def __init__(self, server, parent=None):
+        """Construct the client wrapper with the given parent. All clients
+           connecting to the QWebSocketServer will be automatically wrapped
+           in WebSocketTransport objects."""
+        super(WebSocketClientWrapper, self).__init__(parent)
+        self._server = server
+        self._server.newConnection.connect(self.handleNewConnection)
+        self._transports = []
+
+    @Slot()
+    def handleNewConnection(self):
+        """Wrap an incoming WebSocket connection in a WebSocketTransport
+           object."""
+        socket = self._server.nextPendingConnection()
+        transport = WebSocketTransport(socket)
+        self._transports.append(transport)
+        self.clientConnected.emit(transport)
diff --git a/examples/webchannel/standalone/websockettransport.py b/examples/webchannel/standalone/websockettransport.py
new file mode 100644
index 000000000..4e42e7674
--- /dev/null
+++ b/examples/webchannel/standalone/websockettransport.py
@@ -0,0 +1,88 @@
+#############################################################################
+##
+## Copyright (C) 2017 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Milian Wolff <milian.wolff@kdab.com>
+## Copyright (C) 2020 The Qt Company Ltd.
+## Contact: http://www.qt.io/licensing/
+##
+## This file is part of the Qt for Python examples of the Qt Toolkit.
+##
+## $QT_BEGIN_LICENSE:BSD$
+## You may use this file under the terms of the BSD license as follows:
+##
+## "Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions are
+## met:
+##   * Redistributions of source code must retain the above copyright
+##     notice, this list of conditions and the following disclaimer.
+##   * Redistributions in binary form must reproduce the above copyright
+##     notice, this list of conditions and the following disclaimer in
+##     the documentation and/or other materials provided with the
+##     distribution.
+##   * Neither the name of The Qt Company Ltd nor the names of its
+##     contributors may be used to endorse or promote products derived
+##     from this software without specific prior written permission.
+##
+##
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+from PySide2.QtWebChannel import QWebChannelAbstractTransport
+from PySide2.QtCore import QByteArray, QJsonDocument, Slot
+
+
+class WebSocketTransport(QWebChannelAbstractTransport):
+    """QWebChannelAbstractSocket implementation using a QWebSocket internally.
+
+        The transport delegates all messages received over the QWebSocket over
+        its textMessageReceived signal. Analogously, all calls to
+        sendTextMessage will be sent over the QWebSocket to the remote client.
+    """
+
+    def __init__(self, socket):
+        """Construct the transport object and wrap the given socket.
+           The socket is also set as the parent of the transport object."""
+        super(WebSocketTransport, self).__init__(socket)
+        self._socket = socket
+        self._socket.textMessageReceived.connect(self.textMessageReceived)
+        self._socket.disconnected.connect(self._disconnected)
+
+    def __del__(self):
+        """Destroys the WebSocketTransport."""
+        self._socket.deleteLater()
+
+    def _disconnected(self):
+        self.deleteLater()
+
+    def sendMessage(self, message):
+        """Serialize the JSON message and send it as a text message via the
+           WebSocket to the client."""
+        doc = QJsonDocument(message)
+        json_message = str(doc.toJson(QJsonDocument.Compact), "utf-8")
+        self._socket.sendTextMessage(json_message)
+
+    @Slot(str)
+    def textMessageReceived(self, message_data_in):
+        """Deserialize the stringified JSON messageData and emit
+           messageReceived."""
+        message_data = QByteArray(bytes(message_data_in, encoding='utf8'))
+        message = QJsonDocument.fromJson(message_data)
+        if message.isNull():
+            print("Failed to parse text message as JSON object:", message_data)
+            return
+        if not message.isObject():
+            print("Received JSON message that is not an object: ", message_data)
+            return
+        self.messageReceived.emit(message.object(), self)