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Qt开发笔记：QWebSocket客户端、服务端介绍与开发

前话

Qt提供的WebSocket功能。

Demo演示

Demo下载地址

包含可执行程序和源码。

https://download.csdn.net/download/qq21497936/11666770

WebSocket客户端：QWebSocket

简介

实现一个TCP套接字，该套接字与WebSocket协议进行通信。

WebSockets是一种通过单个TCP连接提供全双工通信通道的Web技术。WebSocket协议在2011年被IETF标准化为RFC 6455。QWebSocket既可用于客户端应用程序，也可用于服务器应用程序。

WebSockets的使用参照QTcpServer。

QWebSocket这个类是根据QAbstractSocket建模的。

QWebSocket当前不支持WebSocket扩展和WebSocket子工具。

QWebSocket仅支持WebSocket协议的版本13，如RFC6455所述。

注意：有些代理不理解WebSocket握手过程中使用的某些HTTP头。在这种情况下，不安全的WebSocket连接会失败。缓解此问题的最佳方法是在安全连接上使用WebSocket。

警告：要生成掩码，WebSockets的此实现使用加密不安全的qrand()函数。有关良好遮蔽的重要性的更多信息，请参见林顺煌等人的“与自己交谈，寻求乐趣和利益”。防范上述文档中提到的攻击的最佳措施是通过安全连接（wss://）使用QWebSocket。一般来说，请务必小心不要让第三方脚本访问应用程序中的QWebSocket。

使用

在工程文件夹中添加:

QT += websockets

包含该类

#include <QWebSocket>

使用时先new一个QWebsocket，然后关联其connected()，disconnected()，error()，textFrameReceived()（或者textMessageReceived()信号，两个收到消息的信号都会触发），发送调用sendTextMessage()函数即可。

关键代码

WebSocketClientManager.h

#ifndef WEBSOCKETCLIENTMANAGER_H
#define WEBSOCKETCLIENTMANAGER_H

/************************************************************\
 * 控件名称： WebSocket客户端管理类
 * 控件描述：
 *          1.类似于QTcpServer操作
 * 作者：红模仿    联系方式：QQ21497936
 * 博客地址：https://blog.csdn.net/qq21497936
 *       日期             版本         描述
 *   2019年09月04日      v1.0.0      基础功能
\************************************************************/

#include <QObject>
#include <QWebSocket>

class WebSocketClientManager : public QObject
{
    Q_OBJECT
public:
    explicit WebSocketClientManager(QObject *parent = nullptr);
    ~WebSocketClientManager();

public:
    bool running() const;

    QString url() const;
    void setUrl(const QString &url);

signals:
    void signal_connected();
    void signal_disconnected();
    void signal_sendTextMessageResult(bool result);
    void signal_sendBinaryMessageResult(bool result);
    void signal_error(QString errorString);
    void signal_textFrameReceived(QString frame, bool isLastFrame);
    void signal_textMessageReceived(QString message);

public slots:
    void slot_start();
    void slot_stop();
    void slot_connectedTo(QString url);
    void slot_sendTextMessage(const QString &message);
    void slot_sendBinaryMessage(const QByteArray &data);

protected slots:
    void slot_connected();
    void slot_disconnected();
    void slot_error(QAbstractSocket::SocketError error);
    void slot_textFrameReceived(const QString &frame, bool isLastFrame);
    void slot_textMessageReceived(const QString &message);

private:
    bool _running;
    QString _url;
    bool _connected;
    QWebSocket *_pWebSocket;
};

#endif // WEBSOCKETCLIENTMANAGER_H

WebSocketClientManager.cpp

#include "WebSocketClientManager.h"
#include <QDebug>

WebSocketClientManager::WebSocketClientManager(QObject *parent)
    : QObject(parent),
    _running(false),
    _pWebSocket(0),
    _connected(false)
{

}

WebSocketClientManager::~WebSocketClientManager()
{
    if(_pWebSocket != 0)
    {
        _pWebSocket->deleteLater();
        _pWebSocket = 0;
    }
}

bool WebSocketClientManager::running() const
{
    return _running;
}

void WebSocketClientManager::slot_start()
{
    if(_running)
    {
        qDebug() << __FILE__ << __LINE__
                 << "Failed to" << __FUNCTION__ << "it's already running...";
        return;
    }
    if(!_pWebSocket)
    {
        _pWebSocket = new QWebSocket();
        connect(_pWebSocket, SIGNAL(connected())   , this, SLOT(slot_connected())   );
        connect(_pWebSocket, SIGNAL(disconnected()), this, SLOT(slot_disconnected()));
        connect(_pWebSocket, SIGNAL(error(QAbstractSocket::SocketError)),
                this       , SLOT(slot_error(QAbstractSocket::SocketError)));
        connect(_pWebSocket, SIGNAL(textFrameReceived(QString,bool)),
                this       , SLOT(slot_textFrameReceived(QString,bool)));
        connect(_pWebSocket, SIGNAL(textMessageReceived(QString)),
                this       , SLOT(slot_textMessageReceived(QString)));
    }
    _running = true;
}

void WebSocketClientManager::slot_stop()
{
    if(!_running)
    {
        qDebug() << __FILE__ << __LINE__
                 << "Failed to" << __FUNCTION__
                 << ", it's not running...";
        return;
    }
    _running = false;
    _pWebSocket->close();
}

void WebSocketClientManager::slot_connectedTo(QString url)
{
    if(!_running)
    {
        qDebug() << __FILE__ << __LINE__
                 << "Failed to" << __FUNCTION__
                 << ", it's not running...";
        return;
    }
    _pWebSocket->open(QUrl(url));
}

void WebSocketClientManager::slot_sendTextMessage(const QString &message)
{
    if(!_running)
    {
        qDebug() << __FILE__ << __LINE__
                 << "Failed to" << __FUNCTION__
                 << ", it's not running...";
        return;
    }
    bool result = true;
    _pWebSocket->sendTextMessage(message);
    emit signal_sendTextMessageResult(result);
}

void WebSocketClientManager::slot_sendBinaryMessage(const QByteArray &data)
{
    if(!_running)
    {
        qDebug() << __FILE__ << __LINE__
                 << "Failed to" << __FUNCTION__
                 << ", it's not running...";
        return;
    }
    bool result = true;
    _pWebSocket->sendBinaryMessage(data);
    emit signal_sendBinaryMessageResult(result);
}

void WebSocketClientManager::slot_connected()
{
    _connected = true;
    qDebug() << __FILE__ << __LINE__ << "connected";
    emit signal_connected();
}

void WebSocketClientManager::slot_disconnected()
{
    _connected = false;
    qDebug() << __FILE__ << __LINE__ << "disconnected";
    emit signal_disconnected();
}

void WebSocketClientManager::slot_error(QAbstractSocket::SocketError error)
{
    qDebug() << __FILE__ << __LINE__ << (int)error << _pWebSocket->errorString();
    emit signal_error(_pWebSocket->errorString());
}

void WebSocketClientManager::slot_textFrameReceived(const QString &frame, bool isLastFrame)
{
    emit signal_textFrameReceived(frame, isLastFrame);
}

void WebSocketClientManager::slot_textMessageReceived(const QString &message)
{
    emit signal_textMessageReceived(message);
}

QString WebSocketClientManager::url() const
{
    return _url;
}

void WebSocketClientManager::setUrl(const QString &url)
{
    _url = url;
}

WebSocket服务端：QWebSocketServer

简介

实现基于WebSocket的服务器。

它是以QTcpServer为模型的，并且行为相同。使用参照QTcpServer。这个类使得接受传入的WebSocket连接成为可能。您可以指定端口或让QWebSocketServer自动选择一个端口。您可以监听一个特定的地址或机器的所有地址。调用listen()让服务器监听传入的连接。

然后，每次客户端连接到服务器时都会发出newConnection()信号。调用nextPendingConnection()将挂起的连接接受为已连接的QWebSocket。函数返回指向QabstractSocket::ConnectedState中QWebSocket的指针，可以使用该指针与客户端通信。

如果发生错误，ServerError()返回错误类型，并且可以调用ErrorString()以获取对所发生情况的人类可读描述。

侦听连接时，服务器正在侦听的地址和端口可用作serverAddress()和serverPort()。

调用close()将使QWebSocketServer停止侦听传入的连接。

QWebSocket服务器当前不支持WebSocket扩展和WebSocket子工具。

注意：使用自签名证书时，Firefox bug 594502会阻止firefox连接到安全的Websocket服务器。要解决此问题，请首先使用https浏览到安全WebSocket服务器。Firefox将指示证书无效。从这里开始，可以将证书添加到异常中。在这之后，安全WebSockets连接应该可以工作。

QWebSocketServer仅支持WebSocket协议的版本13，如RFC6455所述。

枚举

enum QWebSocketServer::SslMode

指示服务器是通过wss（SecureMode）还是ws（NonSecureMode）运行。

使用

在工程文件夹中添加:

QT += websockets

包含该类

#include <QWebSocketServer>

使用时先new一个QWebSocketServer,传入服务器名称和是否使用安全模式（安全模式wss，非安全模式ws），然后关联其newConnected()，closed()，serverError()。

当收到新的连接后，则是转换为QWebSocket，然后关联其connected()，disconnected()，error()，textFrameReceived()（或者textMessageReceived()信号，两个收到消息的信号都会触发），发送调用sendTextMessage()函数即。

关键代码

WebSocketServerManager.h

#ifndef WEBSOCKETSERVERMANAGER_H
#define WEBSOCKETSERVERMANAGER_H

/************************************************************\
 * 控件名称： WebSocket服务器管理类
 * 控件描述：
 *          1.类似于QTcpSocket操作
 * 作者：红模仿    联系方式：QQ21497936
 * 博客地址：https://blog.csdn.net/qq21497936
 *       日期             版本         描述
 *   2019年09月04日      v1.0.0      基础功能
\************************************************************/

#include <QObject>
#include <QWebSocketServer>
#include <QThread>

class WebSocketServerManager : public QObject
{
    Q_OBJECT
public:
    explicit WebSocketServerManager(QString serverName,
                                    QWebSocketServer::SslMode secureMode = QWebSocketServer::NonSecureMode,
                                    QObject *parent = 0);
    ~WebSocketServerManager();

public:
    bool running() const;

signals:
    void signal_conncted(QString ip, qint32 port);
    void signal_disconncted(QString ip, qint32 port);
    void signal_sendTextMessageResult(QString ip, quint32 port, bool result);
    void signal_sendBinaryMessageResult(QString ip, quint32 port, bool result);
    void signal_error(QString ip, quint32 port, QString errorString);
    void signal_textFrameReceived(QString ip, quint32 port, QString frame, bool isLastFrame);
    void signal_textMessageReceived(QString ip, quint32 port,QString message);
    void signal_close();

public slots:
    void slot_start(QHostAddress hostAddress = QHostAddress(QHostAddress::Any), qint32 port = 10080);
    void slot_stop();
    void slot_sendData(QString ip, qint32 port, QString message);

protected slots:
    void slot_newConnection();
    void slot_serverError(QWebSocketProtocol::CloseCode closeCode);
    void slot_closed();

protected slots:
    void slot_disconnected();
    void slot_error(QAbstractSocket::SocketError error);
    void slot_textFrameReceived(const QString &frame, bool isLastFrame);
    void slot_textMessageReceived(const QString &message);

private:
    QString _serverName;
    QWebSocketServer::SslMode _sslMode;
    bool _running;
    QWebSocketServer *_pWebSocketServer;
    QHash<QString, QWebSocket*> _hashIpPort2PWebSocket;
    QHostAddress _listenHostAddress;
    qint32 _listenPort;
};
#endif // WEBSOCKETSERVERMANAGER_H

WebSocketServerManager.cpp

#include "WebSocketServerManager.h"
#include <QDebug>
#include <QWebSocket>

WebSocketServerManager::WebSocketServerManager(QString serverName,
                                               QWebSocketServer::SslMode secureMode,
                                               QObject *parent)
    : QObject(parent),
      _serverName(serverName),
      _sslMode(secureMode),
      _running(false),
      _pWebSocketServer(0)
{
}

WebSocketServerManager::~WebSocketServerManager()
{
    if(_pWebSocketServer != 0)
    {
        _pWebSocketServer->deleteLater();
        _pWebSocketServer = 0;
    }
}

bool WebSocketServerManager::running() const
{
    return _running;
}

void WebSocketServerManager::slot_start(QHostAddress hostAddress, qint32 port)
{
    if(_running)
    {
        qDebug() << __FILE__ << __LINE__
                 << "Failed to" << __FUNCTION__ << "it's already running...";
        return;
    }
    if(!_pWebSocketServer)
    {
        _pWebSocketServer = new QWebSocketServer(_serverName, _sslMode, 0);
        connect(_pWebSocketServer, SIGNAL(newConnection()), this, SLOT(slot_newConnection()));
        connect(_pWebSocketServer, SIGNAL(closed()), this, SLOT(slot_closed()));
        connect(_pWebSocketServer, SIGNAL(serverError(QWebSocketProtocol::CloseCode)),
                this             , SLOT(slot_serverError(QWebSocketProtocol::CloseCode)));
    }
    _listenHostAddress = hostAddress;
    _listenPort = port;
    _pWebSocketServer->listen(_listenHostAddress, _listenPort);
    _running = true;
}

void WebSocketServerManager::slot_stop()
{
    if(!_running)
    {
        qDebug() << __FILE__ << __LINE__
                 << "Failed to" << __FUNCTION__
                 << ", it's not running...";
        return;
    }
    _running = false;
    _pWebSocketServer->close();
}

void WebSocketServerManager::slot_sendData(QString ip, qint32 port, QString message)
{
    QString key = QString("%1-%2").arg(ip).arg(port);
    if(_hashIpPort2PWebSocket.contains(key))
    {
        _hashIpPort2PWebSocket.value(key)->sendTextMessage(message);
    }
}

void WebSocketServerManager::slot_newConnection()
{
    QWebSocket *pWebSocket = _pWebSocketServer->nextPendingConnection();
    connect(pWebSocket, SIGNAL(disconnected()), this, SLOT(slot_disconnected()));
    connect(pWebSocket, SIGNAL(error(QAbstractSocket::SocketError)),
            this      , SLOT(slot_error(QAbstractSocket::SocketError)));
    // 既会触发frame接收也会触发message接收
//    connect(pWebSocket, SIGNAL(textFrameReceived(QString,bool)),
//            this      , SLOT(slot_textFrameReceived(QString,bool)));
    connect(pWebSocket, SIGNAL(textMessageReceived(QString)),
            this      , SLOT(slot_textMessageReceived(QString)));
    _hashIpPort2PWebSocket.insert(QString("%1-%2").arg(pWebSocket->peerAddress().toString())
                                  .arg(pWebSocket->peerPort()),
                                  pWebSocket);
    qDebug() << __FILE__ << __LINE__ << pWebSocket->peerAddress().toString() << pWebSocket->peerPort();
    emit signal_conncted(pWebSocket->peerAddress().toString(), pWebSocket->peerPort());
}

void WebSocketServerManager::slot_serverError(QWebSocketProtocol::CloseCode closeCode)
{
    QWebSocket *pWebSocket = dynamic_cast<QWebSocket *>(sender());
    if(!pWebSocket)
    {
        return;
    }
    emit signal_error(pWebSocket->peerAddress().toString(), pWebSocket->peerPort(), _pWebSocketServer->errorString());
}

void WebSocketServerManager::slot_closed()
{
    QList<QWebSocket *> _listWebSocket = _hashIpPort2PWebSocket.values();
    for(int index = 0; index < _listWebSocket.size(); index++)
    {
        _listWebSocket.at(index)->close();
    }
    _hashIpPort2PWebSocket.clear();
    emit signal_close();
}

void WebSocketServerManager::slot_disconnected()
{
    qDebug() << __FILE__ << __LINE__ << __FUNCTION__;
    QWebSocket *pWebSocket = dynamic_cast<QWebSocket *>(sender());
    if(!pWebSocket)
    {
        return;
    }
    qDebug() << __FILE__ << __LINE__ << __FUNCTION__;
    emit signal_disconncted(pWebSocket->peerAddress().toString(), pWebSocket->peerPort());
    _hashIpPort2PWebSocket.remove(QString("%1-%2").arg(pWebSocket->peerAddress().toString())
                                                  .arg(pWebSocket->peerPort()));
}

void WebSocketServerManager::slot_error(QAbstractSocket::SocketError error)
{
    QWebSocket *pWebSocket = dynamic_cast<QWebSocket *>(sender());
    if(!pWebSocket)
    {
        return;
    }
    emit signal_error(pWebSocket->peerAddress().toString(), pWebSocket->peerPort(), pWebSocket->errorString());
}

void WebSocketServerManager::slot_textFrameReceived(const QString &frame, bool isLastFrame)
{
    QWebSocket *pWebSocket = dynamic_cast<QWebSocket *>(sender());
    if(!pWebSocket)
    {
        return;
    }
    qDebug() << __FILE__ << __LINE__ << frame << isLastFrame;
    emit signal_textFrameReceived(pWebSocket->peerAddress().toString(), pWebSocket->peerPort(), frame, isLastFrame);
}

void WebSocketServerManager::slot_textMessageReceived(const QString &message)
{
    QWebSocket *pWebSocket = dynamic_cast<QWebSocket *>(sender());
    if(!pWebSocket)
    {
        return;
    }
    emit signal_textMessageReceived(pWebSocket->peerAddress().toString(), pWebSocket->peerPort(), message);
}