Websocket and multiple connections after disconnect

Mark81

I'm not sure if this problem is on the Javascript side or Qt side.
On my web page I have this js code:

var ws = null;

var _open = function(address) {
    ws = new WebSocket(address);
    ws.onopen = onOpen;
    ws.onclose = onClose;
    ws.onmessage = onMessage;
    ws.onerror = onError;
};

var close = function() {
    if (ws) ws.close();
};

var onOpen = function() {
    // do something
};

var onClose = function() {
    ws = null;
    retry();
};

var onError = function(event) {
    ws = null;
    retry();
};

var onMessage = function(event) {
    // do something
};

var retry = function() {
    setTimeout(function() { 
        // extract what I need from location.href
        var address = composeWsAddress(extractHostname(location.href));
        _open(address);
    }, 3000);
};

WebSocketClient = {
    init: function() {
        var address = composeWsAddress(extractHostname(location.href));
        _open(address);
    }
};

The goal is to try to reconnect every 3s if the server is not reachable.
Here my Qt code:

#include "wsserver.h"
#define DEBUG

WsServer::WsServer(QObject *parent) : QObject(parent), _wsServer(new QWebSocketServer("myWS", QWebSocketServer::NonSecureMode, this)) { }

WsServer::~WsServer()
{
    _wsServer->close();
    qDeleteAll(_listClients.begin(), _listClients.end());
}

void WsServer::open(quint16 port)
{
    if (_wsServer->listen(QHostAddress::Any, port))
    {
#ifdef DEBUG
        qInfo().noquote() << "[WS] WebSocket server is listening on port" << port;
#endif
        connect(_wsServer, &QWebSocketServer::newConnection, this, &WsServer::newConnection);
        connect(_wsServer, &QWebSocketServer::closed, this, &WsServer::closed);
    }
    else
    {
        qInfo().noquote() << "[WS] Failed to start WebSocket server on port" << port;
    }
}

void WsServer::sendTextMessage(QString message)
{
    foreach (QWebSocket *client, _listClients)
    {
        client->sendTextMessage(message);
    }
}

void WsServer::newConnection()
{
    QWebSocket *socket = _wsServer->nextPendingConnection();

    connect(socket, &QWebSocket::textMessageReceived, this, &WsServer::processTextMessage);
    connect(socket, &QWebSocket::binaryMessageReceived, this, &WsServer::processBinaryMessage);
    connect(socket, &QWebSocket::disconnected, this, &WsServer::socketDisconnected);
    _listClients.append(socket);
    qDebug().noquote() << "[WS] New connection. Client count:" << _listClients.count();
    emit opened();
}

void WsServer::socketDisconnected()
{
    QWebSocket *socket = qobject_cast<QWebSocket *>(sender());
#ifdef DEBUG
    qDebug().noquote() << "[WS] Socket disconnected" << socket;
#endif
    if (socket)
    {
        _listClients.removeAll(socket);
        socket->deleteLater();
    }
}

void WsServer::processTextMessage(QString message)
{
#ifdef DEBUG
    qDebug().noquote() << "[WS] Text message received:" << message;
#endif
    emit textMessageReceived(message);
}

void WsServer::processBinaryMessage(QByteArray message)
{
#ifdef DEBUG
    qDebug().noquote() << "[WS] Binary message received:" << message;
#endif
    emit binaryMessageReceived(message);
}

Now a test case.

run the Qt application and open the web page

[WS] WebSocket server is listening on port 443
[WS] New connection. Client count: 1

stop the Qt application for some time, then run again (keeping open the web page)

[WS] WebSocket server is listening on port 443
[WS] New connection. Client count: 1
[WS] New connection. Client count: 2
[WS] New connection. Client count: 3
[WS] New connection. Client count: 4
[WS] New connection. Client count: 5

As you can see the problem is when the server is not reachable, all the failed connections are kept even if I create a new WebSocket object.

What is the correct way to try again a connection without this annoying side-effect?

Bleach

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