main.cpp Example File

** Copyright (C) 2014 Klarälvdalens Datakonsult AB, a KDAB Group company,, author Milian Wolff <>
** Contact:
** This file is part of the QtWebChannel module of the Qt Toolkit.
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** GNU Lesser General Public License Usage
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** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
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#include "qwebchannel.h"

#include <QApplication>
#include <QDialog>
#include <QVariantMap>
#include <QDesktopServices>
#include <QUrl>
#include <QDir>
#include <QFileInfo>
#include <QtWebSockets/QWebSocketServer>

#include "../shared/websocketclientwrapper.h"
#include "../shared/websockettransport.h"

#include "ui_dialog.h"

    An instance of this class gets published over the WebChannel and is then accessible to HTML clients.
class Dialog : public QObject

    explicit Dialog(QObject *parent = 0)
        : QObject(parent)

        connect(ui.send, SIGNAL(clicked()), SLOT(clicked()));

    void displayMessage(const QString &message)

        This signal is emitted from the C++ side and the text displayed on the HTML client side.
    void sendText(const QString &text);

public slots:
        This slot is invoked from the HTML client side and the text displayed on the server side.
    void receiveText(const QString &text)
        displayMessage(tr("Received message: %1").arg(text));

private slots:
        Note that this slot is private and thus not accessible to HTML clients.
    void clicked()
        const QString text = ui.input->text();

        if (text.isEmpty()) {

        emit sendText(text);
        displayMessage(tr("Sent message: %1").arg(text));


    QDialog dialog;
    Ui::Dialog ui;

int main(int argc, char** argv)
    QApplication app(argc, argv);

    QFileInfo jsFileInfo(QDir::currentPath() + "/qwebchannel.js");

    if (!jsFileInfo.exists())

    // setup the QWebSocketServer
    QWebSocketServer server(QStringLiteral("QWebChannel Standalone Example Server"), QWebSocketServer::NonSecureMode);
    if (!server.listen(QHostAddress::LocalHost, 12345)) {
        qFatal("Failed to open web socket server.");
        return 1;

    // wrap WebSocket clients in QWebChannelAbstractTransport objects
    WebSocketClientWrapper clientWrapper(&server);

    // setup the channel
    QWebChannel channel;
    QObject::connect(&clientWrapper, &WebSocketClientWrapper::clientConnected,
                     &channel, &QWebChannel::connectTo);

    // setup the dialog and publish it to the QWebChannel
    Dialog dialog;
    channel.registerObject(QStringLiteral("dialog"), &dialog);

    // open a browser window with the client HTML page
    QUrl url = QUrl::fromLocalFile(BUILD_DIR "/index.html");

    dialog.displayMessage(QObject::tr("Initialization complete, opening browser at %1.").arg(url.toDisplayString()));

    return app.exec();

#include "main.moc"

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