- Qt 5.15
- Qt WebSockets
- QWebSocket client example
- Qt 5.15.16 Reference Documentation

# QWebSocket client example

## 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.

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

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

     void EchoClient::onConnected()
     {
         if (m_debug)
             qDebug() << "WebSocket connected";
         connect(&m_webSocket, &QWebSocket::textMessageReceived,
                 this, &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.

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

Whenever a message is received, we write it out.