如何在 PyQt5 中使用 QWebSocket 创建 websocket 客户端

Posted 2023-02-16

【中文标题】如何在 PyQt5 中使用 QWebSocket 创建 websocket 客户端

【英文标题】：How to create a websocket client by using QWebSocket in PyQt5

【发布时间】：2016-02-06 04:14:33

【问题描述】：

我想在 PyQt5 中使用 QWebSocket 创建一个 websocket 客户端。为了方便，假设我有一个 websocket 服务器，源代码是这样的，

from PyQt5 import QtCore, QtWebSockets, QtNetwork, QtGui
from PyQt5.QtWidgets import QApplication, QMainWindow, QMenu, QAction
from PyQt5.QtCore import QUrl

class MyServer(QtCore.QObject):
    def __init__(self, parent):
        super(QtCore.QObject, self).__init__(parent)
        self.clients = []
        self.server = QtWebSockets.QWebSocketServer(parent.serverName(), parent.secureMode(), parent)
        if self.server.listen(QtNetwork.QHostAddress.LocalHost, 1302):
            print('Connected: '+self.server.serverName()+' : '
                  +self.server.serverAddress().toString()+':'+str(self.server.serverPort()))
        else:
            print('error')
        self.server.newConnection.connect(self.onNewConnection)
        self.clientConnection = None
        print(self.server.isListening())

    def onNewConnection(self):
        self.clientConnection = self.server.nextPendingConnection()
        self.clientConnection.textMessageReceived.connect(self.processTextMessage)

        self.clientConnection.binaryMessageReceived.connect(self.processBinaryMessage)
        self.clientConnection.disconnected.connect(self.socketDisconnected)

        print("newClient")
        self.clients.append(self.clientConnection)

    def processTextMessage(self, message):
        print(message)
        if self.clientConnection:
            for client in self.clients:
                # if client!= self.clientConnection:
                client.sendTextMessage(message)
            # self.clientConnection.sendTextMessage(message)

    def processBinaryMessage(self, message):
        print("b:",message)
        if self.clientConnection:
            self.clientConnection.sendBinaryMessage(message)

    def socketDisconnected(self):
        if self.clientConnection:
            self.clients.remove(self.clientConnection)
            self.clientConnection.deleteLater()

if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    serverObject = QtWebSockets.QWebSocketServer('My Socket', QtWebSockets.QWebSocketServer.NonSecureMode)
    server = MyServer(serverObject)
    serverObject.closed.connect(app.quit)
    app.exec_()

它可以创建一个websocket服务器，我使用javascript对其进行测试，它工作正常。但是我可以找到一种使用Qwebsocket创建客户端的方法。我的客户端代码是这样的：

client =  QtWebSockets.QWebSocket("",QtWebSockets.QWebSocketProtocol.Version13,None)
client.open(QUrl("ws://127.0.0.1:1302"))
client.sendTextMessage("asd")
client.close()

服务器好像没有收到客户端发送的消息，如何创建websocket客户端并使用Qwebsocket发送消息？

【参考方案1】：

这是 qt 控制台程序的典型问题，您需要在 python 构造函数之外调用客户端方法 (__init__)。

我稍微修改了你的服务器，添加了一些错误测试（没什么新东西）：

from PyQt5 import QtCore, QtWebSockets, QtNetwork, QtGui
from PyQt5.QtWidgets import QApplication, QMainWindow, QMenu, QAction
from PyQt5.QtCore import QUrl

class MyServer(QtCore.QObject):
    def __init__(self, parent):
        super(QtCore.QObject, self).__init__(parent)
        self.clients = []
        print("server name: ".format(parent.serverName()))
        self.server = QtWebSockets.QWebSocketServer(parent.serverName(), parent.secureMode(), parent)
        if self.server.listen(QtNetwork.QHostAddress.LocalHost, 1302):
            print('Listening: ::'.format(
                self.server.serverName(), self.server.serverAddress().toString(),
                str(self.server.serverPort())))
        else:
            print('error')
        self.server.acceptError.connect(self.onAcceptError)
        self.server.newConnection.connect(self.onNewConnection)
        self.clientConnection = None
        print(self.server.isListening())

    def onAcceptError(accept_error):
        print("Accept Error: ".format(accept_error))

    def onNewConnection(self):
        print("onNewConnection")
        self.clientConnection = self.server.nextPendingConnection()
        self.clientConnection.textMessageReceived.connect(self.processTextMessage)

        self.clientConnection.textFrameReceived.connect(self.processTextFrame)

        self.clientConnection.binaryMessageReceived.connect(self.processBinaryMessage)
        self.clientConnection.disconnected.connect(self.socketDisconnected)

        print("newClient")
        self.clients.append(self.clientConnection)

    def processTextFrame(self, frame, is_last_frame):
        print("in processTextFrame")
        print("\tFrame:  ; is_last_frame: ".format(frame, is_last_frame))

    def processTextMessage(self, message):
        print("processTextMessage - message: ".format(message))
        if self.clientConnection:
            for client in self.clients:
                # if client!= self.clientConnection:
                client.sendTextMessage(message)
            # self.clientConnection.sendTextMessage(message)

    def processBinaryMessage(self, message):
        print("b:",message)
        if self.clientConnection:
            self.clientConnection.sendBinaryMessage(message)

    def socketDisconnected(self):
        print("socketDisconnected")
        if self.clientConnection:
            self.clients.remove(self.clientConnection)
            self.clientConnection.deleteLater()

if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    serverObject = QtWebSockets.QWebSocketServer('My Socket', QtWebSockets.QWebSocketServer.NonSecureMode)
    server = MyServer(serverObject)
    serverObject.closed.connect(app.quit)
    app.exec_()

客户端使用一些QTimer在__init__方法之外调用所需的方法。我还添加了 ping / pong 方法来检查连接：

import sys

from PyQt5 import QtCore, QtWebSockets, QtNetwork
from PyQt5.QtCore import QUrl, QCoreApplication, QTimer
from PyQt5.QtWidgets import QApplication


class Client(QtCore.QObject):
    def __init__(self, parent):
        super().__init__(parent)

        self.client =  QtWebSockets.QWebSocket("",QtWebSockets.QWebSocketProtocol.Version13,None)
        self.client.error.connect(self.error)

        self.client.open(QUrl("ws://127.0.0.1:1302"))
        self.client.pong.connect(self.onPong)

    def do_ping(self):
        print("client: do_ping")
        self.client.ping(b"foo")

    def send_message(self):
        print("client: send_message")
        self.client.sendTextMessage("asd")

    def onPong(self, elapsedTime, payload):
        print("onPong - time:  ; payload: ".format(elapsedTime, payload))

    def error(self, error_code):
        print("error code: ".format(error_code))
        print(self.client.errorString())

    def close(self):
        self.client.close()

def quit_app():
    print("timer timeout - exiting")
    QCoreApplication.quit()

def ping():
    client.do_ping()

def send_message():
    client.send_message()

if __name__ == '__main__':
    global client
    app = QApplication(sys.argv)

    QTimer.singleShot(2000, ping)
    QTimer.singleShot(3000, send_message)
    QTimer.singleShot(5000, quit_app)

    client = Client(app)

    app.exec_()

服务器输出：

G:\Qt\QtTests>python so_qwebsocket_server.py
server name: My Socket
Listening: My Socket:127.0.0.1:1302
True
onNewConnection
newClient
in processTextFrame
        Frame: asd ; is_last_frame: True
processTextMessage - message: asd
socketDisconnected

客户端输出：

G:\Qt\QtTests>python so_qwebsocket_client.py
client: do_ping
onPong - time: 0 ; payload: b'foo'
client: send_message
timer timeout

总而言之，如果您在简单的 GUI 中使用您的客户端（例如，将 client.sendTextMessage() 移动到 __init__ 之外并连接一个按钮单击以实际发送消息），由于其异步性质，它应该可以在没有任何问题！

【讨论】：

谢谢你，你帮了我很多。

嘿，我试图实现服务器......当一个按钮被点击时服务器启动，到目前为止一切都很好。但是当我尝试连接 websocket 客户端（我使用 websocat）时，它连接失败并显示错误消息 ``` websocat: WebSocketError: I/O failure websocat: error running ``` 握手似乎有问题，但是我不确定。你能提供任何见解吗？ （找到解决方案），我需要将当前窗口作为父窗口传递