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Qt QWebSocket network programming

2024-07-12

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Discendi proposita: Qt QWebSocket network programming

Learning pre-environment

QT TCP multi-fila network communicationis CSDN Blog

Learning Content

WebSocket technologiam retis est quae plenam communicationis canalem in unum TCP nexum praebet. Anno 2011 , IETF normatum protocollo WebSocket RFC6455 , et QWebSocket adhiberi potest in applicationibus clientium et applicationes servo.

Plenam communicationem duplicem inter navigatorem et ministratorem instruit, permittens servo ut proactive notitias clienti mitteret.

principale pluma:

  1. Dissimilis HTTP, WebSocket servo permittit ut actuose data clienti mittat non exigente cliente ut petitionem incipiat.

  2. TCP in protocollo aedificata, communicatio plena duplex inter servientem et clientem, in uno portu per Ws (WebSocket) protocollum exercetur.

  3. Data transmissio in textu vel forma binaria sustinet.

  4. Protocollum in uno nexu TCP aedificatum est. Servus et client solum necesse est unum nexum creare et nexum non claudi.

  5. Clientem latus et server lateris bibliothecas in pluribus programmatibus linguarum sustinet, ut JavaScript, Java, C#, Python, etc.

Communia applicatione missionum:

  1. Curabitur volutpat: subsidia humilis latency colloquia real-time.

  2. Online ludum: a synchronisation engine quod requirit real-time synchronisation ludi status.

  3. Stock quotes: Quotation programmata quae necessaria sunt ad ventilandum reale tempus quotes clienti.

  4. Video conferendi: communicationis vocis et videndi requiritur realis tempus Belgicum.

  5. Real-time collaborative emendo: exempli gratia, codicem online editor postulat synchronization real-time.

QWebSocket est munus bibliothecae WebSockete a Qt provisum. Constructum est in modum retis Qt et instrumentis protocollo WebSocket in RFC6455 vexillum. Opus addere QT+=websockets ad Qmake file

  1. QWebSocket tantum sustinet Textus/Nuntium binarium formatorum et alias formas extensas non sustinet. Si aliae protocollae consuetudinis adiciendae sunt, tincidunt opus est ut id ipsum in applicatione tabulato tractandum sit.

  2. Accessum ad operas interretiales adiuvat utentes vexillum http/https portus 80/443, et etiam protocollum (encrypted websocket) sustinet. Ita facile cum servientibus interretialibus correspondent.

  3. Cum in exsequendis nervis QT innitatur, plene omnes functiones retis Qt sustinet, ut procuratores occasus, SSL configurationes, etc. Facilius est hoc uti, quam humili gradu C interfaces.

  4. Sustinet activum et passivum nexum modorum. Vincula activae sunt per connectToHost(), et nexus passivae accipiuntur per portum auditum accept(). Utroque modo valde convenit.

  5. Pro QT GUI applicationes, nuntius receptionis ac renovationes interfacies facile perfici possunt, multiplicitatem programmandi multi-filati vitando. Exempli gratia, iustus renovatio interfaciei directe in textMessageReceived().

  6. Post QT5.10, asynchronum I/O sustentatur, et effectus paulo emendatus ad antecedit. Auxilia ad extensiones retis melius etiam est.

QWebSocket commune membrum functiones

  1.  
  2. origin()
  3. 即 websocket=new QWebSocket("C1我是客户端",QWebSocketProtocol::VersionLatest,this);
  4. websocket->origin()  -》 C1我是客户端
  5.  
  6. void connectToHost(const QUrl &url) - 用于连接到指定主机的websocket服务,这个函数是异步的。
  7. void close() - 关闭与服务器的连接。
  8. void textMessageReceived(const QString &message) - 收到文本消息时触发的信号,其参数就是收到的文本消息内容。
  9. void binaryMessageReceived(const QByteArray &message) - 收到二进制消息时触发的信号,参数是原始二进制数据。
  10. void error(QAbstractSocket::SocketError socketError) - 发生错误时触发的信号,参数是错误类型。
  11. void stateChanged(QAbstractSocket::SocketState state) - 连接状态变化时触发,可以得知连接是否建立等。
  12. void textMessageSent(qint64 numBytes) - 发送文本消息完成后触发,numBytes是字节数。
  13. void bytesWritten(qint64 bytes) - 消息发送过程中的写入回调, bytes是一个部分发送出去的字节数。
  14. void abort() - 主动断开连接。
  15. bool waitForConnected(int msec = 30000) - 阻塞等待连接建立成功。
  17. QString hostName() - 获取当前连接的主机名,常用于判断连接是否成功。
  18. quint16 port() - 获取主机端口号。
  19. bool openMode() - 判断当前是否为主动连接还是被动接受模式。
  20. void writeTextMessage(const QString &text) - 发送文本消息,相比textMessage等更直观。
  21. void writeMessage(const QByteArray &data) - 发送二进制数据。
  22. qint64 bytesAvailable() - 查看接收缓存中可读取字节数。
  23. qint64 readBufferSize() - 设置双向数据接收缓存大小。
  24. void pauseIncomingPayload() - 暂停接收消息流。
  25. void resumeIncomingPayload() - 恢复接收。
  26. bool isValid() - 检查连接是否有效。
  28. 另外,作为QT套接字,它还支持一些通用功能:
  29. void setProxy() - 设置代理。
  30. void encrypt() - 设置SSL安全连接。
  31. void flush() - 强制输出缓存写出。
  32. bool waitForBytesWritten() - 等待数据发送完毕。
  34.  
  35. void QWebSocket::sendTextMessage(const QString &message)  用于发送文本消息
  36. 使用这个函数发送文本消息主要有以下几点需要注意的地方:
  37. 1发送文本消息前请确保WebSocket连接已经建立。可以通过ReadyState判断连接状态。
  38. 2发送的消息内容必须是纯文本,不支持转义编码等更多格式。
  39. 3一条消息发送完毕后,会触发textMessageSent()信号通知。
  40. 4可以通过waitForBytesWritten()等待数据完全发送出去。
  41. 5发送数据顺序可能与收到响应顺序不一致,需要应用层自己处理序号等。
  42. 6若消息较大,建议使用write或send到套接字后flush,而不是sendTextMessage。
  43. 7跨平台考虑,消息内容编码最好使用QString而不是QByteArray。
  44. 8使用该函数发送的文本消息类型,服务端一般对应文本框接受。
  45. 9可以绑定消息发送断开连接的异常处理等。

Ambae functiones mittereTextMessage et scribeTextMessage nuntiis textibus mittere possunt, sed nonnullas differentias habent;

  1. Munus definitio differt;

  • sendTextMessage pertinet ad functionem membri QWebSocket;

  • writeTextMessage membrum functionis QAbstractSocket, et QWebSocket hereditas ex QAbstractSocket.

  1. Mitto alia efficientia;

  • Interne sendTextMessage nuntium in QByteArray convertet primum, et deinde per munus scribentis mitte, quod est unum magis conversionem;

  • writeTextMessage directly writes the QString that needs to sent, which is slightly more efficient.

  1. Async subsidium differt;

  • sendTextMessage est operatio synchrone et iterum post missionem perficitur;

  • scribeTextMessage subsidia asynchronae vocat, et munus callback per Labda definiri potest.

  1. Erroris tractatio alia est;

  • sendTextMessage non revertetur errorum informationes et solum per errores signos tractari potest;

  • writeTextMessage errorem codicem reddidit posse statuere condicionem missionem.

  1. Diversus usus missionum;

  • sendTextMessage focus in WebSocket et apta est ad vocandum WebSocket API;

  • writeTextMessage generalius est et cum aliis QAbstractSocket classibus adhiberi potest.

In genere:

  • sendTextMessage simplicior est ad usum, bene encapsulatum et ad usum fundamentalem accommodatum;

  • writeTextMessage paulo efficacior est, plura lineamenta sustinet sicut asynchronum et errorem tractantem, et ad missiones idonea est cum maximis agendis vel moderandis requisitis.

Intellego project

Privata communicatio inter clientem et clientem, communicatio inter clientem et ministratorem.

core codice

Servo

Processus: QWebServer crea, liga novum nexum callback, et audi disiunctio.

Novus nexus callback: Cum novus nexus collectioni additur, offline et recipiendo et error callbacks ad novum nexum nervum tenentur.

Bulla nuntiorum mitte: omnia et singula indica, collectionem percurre et mitte utendo mittereTextMesg

  1. #include "widget.h"
  2. #include "ui_widget.h"
  3. //这个是服务器端
  4. Widget::Widget(QWidget *parent)
  5.     : QWidget(parent)
  6.     , ui(new Ui::Widget)
  7. {
  8.     ui->setupUi(this);
  9.     /*
  10.      * mode
  11. NonSecureMode: 不安全模式,即不使用SSL/TLS进行通信。这是默认值。
  12. SecureMode: 安全模式,以SSL/TLS安全通信。客户端和服务端之间的连接将使用SSL握手建立安全通道。
  13. AutomaticallyAcceptServerCertificates: 自动接受服务器证书。在SecureMode下,客户端无法验证证书时,自动接受服务器发来的证书以建立连接。
  14. VerifyNone: 不验证证书。以SecureMode运行,但不会验证客户端和服务端使用的证书。
  15. */
  16.     webServer = new QWebSocketServer("testWebServer",QWebSocketServer::NonSecureMode,this);
  17.     QObject::connect(webServer,&QWebSocketServer::newConnection,this,&Widget::MyselfNewConnectCallBackSlot);
  18.  
  19.     webServer->listen(QHostAddress::Any,8888);
  20. }
  21. void Widget::MyselfNewConnectCallBackSlot(){//新连接回调
  22.  
  23.     if(webServer->hasPendingConnections()){
  24.         QWebSocket* websocket=webServer->nextPendingConnection();
  25.         ui->msgtext->append(websocket->origin()+"客户端已连接到服务器");
  26.         sockets<<websocket;
  27.  
  28.         QListWidgetItem * item =new QListWidgetItem;
  29.         item->setText(websocket->origin());
  30.         ui->clinetls->addItem(item);
  31.  
  32.  
  33.         //绑定离开
  34.         QObject::connect(websocket,&QWebSocket::disconnected,this,[websocket,this](){
  35.             ui->msgtext->append(websocket->origin()+"客户端断开服务器连接");
  36.             sockets.removeOne(websocket);
  37.             for(int i=0;i<ui->clinetls->count();i++)
  38.             {
  39.                 QListWidgetItem *item=ui->clinetls->item(i);
  40.  
  41.                 if(item->text()==websocket->origin())
  42.                 {
  43.                     ui->clinetls->removeItemWidget(item);
  44.                     delete item;
  45.                     break;
  46.                 }
  47.             }
  48.  
  49.             websocket->deleteLater();
  50.  
  51.         });
  52.  
  53.  
  54.         //接受消息回调
  55.         QObject::connect(websocket,&QWebSocket::textMessageReceived,this,[this](const QString &msg){
  56.             QJsonDocument doc =QJsonDocument::fromJson(msg.toLatin1().data());
  57.             if(doc.isNull()){
  58.                 QWebSocket* websocket =qobject_cast<QWebSocket*>(sender());//sender 触发信号的源头
  59.                 ui->msgtext->append("收到客户端消息["+websocket->origin()+"]--->"+msg);
  60.  
  61.             }else{
  62.                 //客户端之间的单发消息
  63.                 QJsonObject obj=doc.object();
  64.                 QString dst=doc["dst"].toString();
  65.                 for (auto& socket : sockets) {
  66.                     if(dst == socket->origin()){
  67.                         socket->sendTextMessage(msg);
  68.                     }
  69.                 }
  70.             }
  71.         });
  72.  
  73.  
  74.         QObject::connect(websocket,QOverload<QAbstractSocket::SocketError>::of(&QWebSocket::error),
  75.                          this,[this](QAbstractSocket::SocketError error){
  76.             QWebSocket* web =qobject_cast<QWebSocket*>(sender());
  77.             ui->msgtext->append(web->origin()+"出错"+web->errorString());
  78.         });
  79.     }
  80.  
  81.  
  82.  
  83. }
  84. Widget::~Widget()
  85. {
  86.     delete ui;
  87.     for(auto socket:sockets)
  88.     {
  89.         socket->close();
  90.     }
  91.  
  92.     webServer->close();
  93. }
  94.  
  95.  
  96. void Widget::on_sendpb_clicked()
  97. {
  98.     QString send =ui->sendtext->toPlainText().trimmed();
  99.     if(send.isEmpty())return;
  100.     if(ui->allradio->isChecked()){
  101.         //群发
  102.         if(sockets.size()==0)return;
  103.         foreach(auto &socket,sockets){
  104.             socket->sendTextMessage(send);
  105.         }
  106.         ui->msgtext->append("服务器给所有连接发送："+send);
  107.     }else{ //私发  取客户端名称 找 发
  108.         if(!ui->clinetls->currentItem())return;
  109.         QString cname =ui->clinetls->currentItem()->text();
  110.  
  111.         for(auto &socket:sockets)
  112.         {
  113.             if(socket->origin()==cname)
  114.             {
  115.                 socket->sendTextMessage(send);
  116.                 ui->msgtext->append("服务端给["+socket->origin()+"]发送--->"+send);
  117.  
  118.                 break;
  119.             }
  120.         }
  121.     }
  122.  
  123.  
  124.     ui->sendtext->clear();
  125. }

clientis

Preme puga pyga ad processum connexionis interretialem efficiendum: creo websocket, varias callbacks liga, et per apertum connect

Button nuntium mitte: nuntiis privatis nuntia et servo nuntia, encapsulate mandata privata in forma json, et tunc mitte.

  1. #include "widget.h"
  2. #include "ui_widget.h"
  3. #include<QMessageBox>
  4. Widget::Widget(QWidget *parent)
  5.     : QWidget(parent)
  6.     , ui(new Ui::Widget)
  7. {
  8.     ui->setupUi(this);
  9.  
  10.     websocket=nullptr;
  11.  
  12. }
  13.  
  14. Widget::~Widget()
  15. {
  16.     delete ui;
  17. }
  18.  
  19.  
  20. void Widget::on_sendpb_clicked()
  21. {
  22.     if(!websocket && !websocket->isValid())
  23.             return;
  24.  
  25.     QString send=ui->sendtext->toPlainText().trimmed();
  26.     if(send.isEmpty())return;
  27.  
  28.  
  29.     QString cname =ui->onetextmsg->text().trimmed();
  30.     if(cname.isEmpty()){ //发给服务器
  31.         websocket->sendTextMessage(send);
  32.         ui->msgtext->append("发送消息："+send);
  33.     }else{
  34.         //私聊发
  35.         QJsonObject obj;
  36.         obj["src"]=websocket->origin();
  37.         obj["dst"]=cname;
  38.         obj["msg"]=send;
  39.         //将一个QJsonObject类型的obj转换成JSON字符串。 Compact参数指定格式化方式为紧凑格式(每个元素占一行)。紧凑格式输出结构清晰,容量小,适合传输和存储。
  40.         QString str(QJsonDocument(obj).toJson(QJsonDocument::Compact));
  41.         websocket->sendTextMessage(str);
  42.     }
  43.     ui->sendtext->clear();
  44.  
  45.  
  46. }
  47.  
  48. void Widget::on_connect_clicked()
  49. {
  50.  
  51.     if(websocket == nullptr){
  52.         if(ui->server_addr->text().trimmed().isEmpty()){
  53.             QMessageBox::critical(this,"错误","服务器名称不能为空，请重新检查!",QMessageBox::Yes);
  54.             return;
  55.         }
  56.         //用于移除字符串开头和结尾处的空白字符。 输入: " test " trimmed()后的结果: "test"  VersionLatest使用最新的websocket协议版本。
  57.         websocket=new QWebSocket(ui->client_name->text().trimmed(),QWebSocketProtocol::VersionLatest,this);
  58.  
  59.         //连接回调
  60.         QObject::connect(websocket,&QWebSocket::connected,this,[this](){
  61.             ui->msgtext->append("已经连接上"+websocket->peerAddress().toString());
  62.             isConnecting=true;
  63.             ui->connect->setText("断开服务器");
  64.         });
  65.         //断开回调
  66.         QObject::connect(websocket,&QWebSocket::disconnected,this,[this](){
  67.             ui->msgtext->append("已"+websocket->peerAddress().toString()+"断开连接");
  68.             isConnecting=false;
  69.             ui->connect->setText("连接服务器");
  70.         });
  71.  
  72.         QObject::connect(websocket,QOverload<QAbstractSocket::SocketError>::of(&QWebSocket::error)
  73.                          ,this,[this](QAbstractSocket::SocketError){
  74.             ui->msgtext->append(websocket->origin()+"出错"+websocket->errorString());
  75.  
  76.         });
  77.  
  78.  
  79.         //接受消息回调 网上知名bug 当你连续发送 A:A*100 B:200时 接收方：A*100200 通过消息队列方式发送即可
  80.         connect(websocket,&QWebSocket::textMessageReceived
  81.                 ,this,[this](const QString &msg){
  82.             QJsonDocument jsd=QJsonDocument::fromJson(msg.toUtf8().data());
  83.  
  84.             if(jsd.isNull()) //解析失败 即没有 c1:c2 客户端与客户端私聊
  85.             {
  86.                 ui->msgtext->append("收到消息:"+msg);
  87.             }
  88.             else
  89.             {
  90.                 QJsonObject jsobj=jsd.object();
  91.                 ui->msgtext->append("收到来自"+jsobj["src"].toString()+"的消息:"+jsobj["msg"].toString());
  92.             }
  93.         },Qt::QueuedConnection);
  94.  
  95.  
  96.  
  97.     }
  98.  
  99.     if(isConnecting){ //连接是成功的
  100.         websocket->close();
  101.         websocket->deleteLater();
  102.         websocket=nullptr;
  103.  
  104.     } else
  105.     {
  106.         websocket->open(QUrl(ui->server_addr->text().trimmed()));
  107.     }
  108. }

Summatim

In genere, QWebSocket, ut component in bibliotheca retis QT, APIs commodum praebet ad explicandum clientes WebSocket et servientes.

Praecipua eius commoda sunt:

  1. Omnino objecto consilio ordinatur, API simplex ac facile utatur.

  2. Magnopere inserti cum aliis QT retis componentibus, ut in subsidium SSL/procuratoris.

  3. Exemplar eventum agitatae utens, tincidunt non opus est agere cum singulis subiacentibus sicut multi-linea.

  4. Naturaliter cum Qt GUI applicationibus, nuntiis ac updates interfacientibus integrata directe vocari possunt.

  5. Plenam exsecutionem praebet specificationum WebSocket fundamentalium, quae ex archa adhiberi possunt ad progressionem faciliorem reddendam.

  6. Etiam perficientur bona est, praesertim cum QT5.10 asynchronum I/O vocantem sustinet.

  7. Exemplaria copiosa et aperta principia incepta praesto sunt ad referendum, et claustrum introitus humile est.

Quaedam puncta notanda sunt:

  1. Aliquae formarum protocolli telae extensae non sustinentur nec opus sunt ut a te ipso perficiantur.

  2. Ordo congruens nuntii mittendi et accipiendi necessitates a te regenda.

  3. Tabella magna et effusis notitiae transmissionis subsidium non satis amicae et directae est.

  4. Subiecta indicibus captiosis et machinae adhibitae memoriae administratione mutari non possunt.

  5. Firmamentum ad novas lineas C++ vexillum respective conservativum est.

Super, QWebSocket praebet optimam et maturam electionem pro plurimis Tcp-substructis applicationibus WebSocket. Altitudo progressionis efficientiae et pauci cimices. QT etiam praeponitur medicamentis. Si requisita sunt altioris gradus, aliae exsecutiones subiectae considerari possunt. Sed in pluribus, QWebSocket satis est.

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