QWebSocket client example

A sample WebSocket client that sends a message and displays the message that it receives back.

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L'auteur

The Qt Company Ltd.

L'article

Publié le 26 janvier 2024 - Mis à jour le 26 janvier 2024

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Description▲

The EchoClient example implements a WebSocket client that sends a message to a WebSocket server and dumps the answer that it gets back. This example should ideally be used with the EchoServer example.

Code▲

We start by connecting to the `connected()` signal.

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EchoClient::EchoClient(const QUrl &amp;url, bool debug, QObject *parent) :
    QObject(parent),
    m_url(url),
    m_debug(debug)
{
    if (m_debug)
        qDebug() &lt;&lt; "WebSocket server:" &lt;&lt; url;
    connect(&amp;m_webSocket, &amp;QWebSocket::connected, this, &amp;EchoClient::onConnected);
    connect(&amp;m_webSocket, &amp;QWebSocket::disconnected, this, &amp;EchoClient::closed);
    m_webSocket.open(QUrl(url));
}

After the connection, we open the socket to the given url.

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void EchoClient::onConnected()
{
    if (m_debug)
        qDebug() &lt;&lt; "WebSocket connected";
    connect(&amp;m_webSocket, &amp;QWebSocket::textMessageReceived,
            this, &amp;EchoClient::onTextMessageReceived);
    m_webSocket.sendTextMessage(QStringLiteral("Hello, world!"));
}

When the client is connected successfully, we connect to the `onTextMessageReceived()` signal, and send out "Hello, world!". If connected with the EchoServer, we will receive the same message back.

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void EchoClient::onTextMessageReceived(QString message)
{
    if (m_debug)
        qDebug() &lt;&lt; "Message received:" &lt;&lt; message;
    m_webSocket.close();
}

Whenever a message is received, we write it out.

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