c++ - Qt和Node JS通过WebSockets进行网络通信

Question

我想将我的 Node JS 应用程序与 Qt(C++) 程序连接起来，我正在为 Node JS(服务器)使用 Socket.io，为 Qt 程序(客户端)使用 QWebSocket。

但在经历了所有的考验之后，我还是没有开始工作。它向我展示了客户端的错误:

QAbstractSocket::RemoteHostClosedError

从服务器端看，没有传入连接的迹象。

这是我的源代码:

Node JS 服务器:

var io = require('socket.io')(8082);

io.on('connection', function (socket) {
  io.emit('this', 'Hey Welcome!');
   console.log("New connection!");

  socket.on('private message', function (from, msg) {
    console.log('I received a private message by ', from, ' saying ', msg);
  });

  socket.on('disconnect', function () {
    io.emit('user disconnected');
  });
});

Qt C++ 客户端:

    #include "widget.h"
#include "ui_widget.h"

Widget::Widget(QWidget *parent) : QWidget(parent),  ui(new Ui::Widget)
{
    ui->setupUi(this);

    webSocket  = new QWebSocket();

    webSocket->open(QUrl(("ws://localhost:8082")));

    connect(webSocket, SIGNAL(connected()), this, SLOT(isConnected()));
    connect(webSocket, SIGNAL(sslErrors(QList<QSslError>)), this, SLOT(sslError(QList<QSslError>)));
    connect(webSocket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(logError(QAbstractSocket::SocketError)));
    connect(webSocket, SIGNAL(textMessageReceived(QString)), this, SLOT(newMessage(QString)));
    connect(webSocket, SIGNAL(textFrameReceived(QString,bool)), this, SLOT(newMessageBit(QString,bool)));
}

Widget::~Widget()
{
    delete ui;
}


void Widget::isConnected()
{
    webSocket->sendTextMessage("Hello From Qt!!!");
}

void Widget::logError(QAbstractSocket::SocketError err)
{
    qDebug() << "Error: ";
    qDebug() << err;
}

void Widget::sslError(QList<QSslError> errors)
{
    qDebug() << "SSLError: ";
    qDebug() << errors;
    webSocket->ignoreSslErrors(errors);
}


void Widget::newMessage(QString msg)
{
    qDebug() << msg;
}

void Widget::newMessageBit(QString msg, bool isLast)
{
    qDebug() << msg;
    qDebug() << isLast;
}

我也从调试控制台得到这些错误(在运行时)

QSslSocket: cannot resolve TLSv1_1_client_method
QSslSocket: cannot resolve TLSv1_2_client_method
QSslSocket: cannot resolve TLSv1_1_server_method
QSslSocket: cannot resolve TLSv1_2_server_method
QSslSocket: cannot resolve SSL_select_next_proto
QSslSocket: cannot resolve SSL_CTX_set_next_proto_select_cb
QSslSocket: cannot resolve SSL_get0_next_proto_negotiated

Answer 1

虽然我迟到了，但如果有人也面临这个问题(不包括 ssl 错误)，它可能会有用。首先，socket.io 与 Qt(或 c++、java、php 或任何其他语言)使用的标准 websockets 不兼容。如果您在服务器上使用 socket.io，那么您只能使用 socket.io 特定的客户端库，而不是标准的 websocket 库。

有几个其他语言的 socket.io 特定客户端库 -

Java: https://github.com/socketio/socket.io-client-java
C++: https://github.com/socketio/socket.io-client-cpp
Swift: https://github.com/socketio/socket.io-client-swift
Dart: https://github.com/rikulo/socket.io-client-dart
Python: https://github.com/miguelgrinberg/python-socketio
.Net: https://github.com/Quobject/SocketIoClientDotNet