如何将传入消息从 web-socket 发送到工作线程？

Question

我正在尝试在 Python 3.7.3 中使用 web-socket 和 pyqt5 构建一个小型应用程序。基本上，我使用两个网络套接字，一个用于触发唤醒词，另一个用于获取意图。我想将此意图数据（JSON 格式）传递给工作线程，该工作线程将进一步检查条件类型，然后在主 GUI 上显示适当的输出。在这里，用户的输入本质上可以是连续的，也可以不是连续的，但无论输入是否来自用户，GUI 和两个 web-socket 都应该连续并行运行。

# Intents are passed through here
def on_message(ws, message):
    data = json.loads(message)
    return data

def on_error(ws, error):
    print("Error from Intent",error)

def on_close(ws):
    print("**Disconnected**")

def on_open(ws):
    print("**Connected**")

# Same way for Wake Word as did above


#GUI starts here
frame_less = QtCore.Qt.WindowFlags(QtCore.Qt.FramelessWindowHint)

#GUI Thread class
class ExecuteThread(QThread):
    # creating signals
    output_signal = pyqtSignal(str)
    finished = pyqtSignal()

    def run(self):
        self.process_intent()

    #checking intent name and executing respective action
    def process_intent(self):
        while True:
            #intent method is being called
            self.intent = on_message()
            if ("GetTime" == self.intent["intent"]["name"]):
                say('GetTime Intent Recognized') #text to speech method
                self.output_signal.emit('GetTime Intent Recognized\n') #should display on GUI
                QThread.msleep(3000)
                self.finished.emit()
            elif:
                #do somthing here as above
            else:
                say('Please Try again') #text to speech method
                self.output_signal.emit('Please Try again') #should display on GUI
                QThread.msleep(3000)
                self.finished.emit()


load_gui,_ = loadUiType('virtual_gui.ui')

#GUI main class
class Main(QMainWindow,load_gui):
    def __init__(self,parent=None):
        super(Main,self).__init__(parent)
        self.setupUi(self)
        self.setFixedSize(1200,800)

        # some other stuff

        #Starting Main Event Funaction
        self.Start_Main_Event()

    def Start_Main_Event(self):
        self.thread = ExecuteThread()
        #connecting signals to respective functions
        self.thread.output_signal.connect(self.output_event)
        self.thread.finished.connect(self.thread_finished)
        self.thread.start()

    def thread_finished(self):
        # gets executed if thread finished
        self.text_output.setText('')
        print('finished')

    def output_event(self,text):
        # gets executed on signal
        self.text_output.setText(text)

#displaying gui function
def main_class():
    App = QApplication(sys.argv)
    win = Main()
    win.show()
    win.showFullScreen ()
    QtWidgets.QApplication.setQuitOnLastWindowClosed(True)
    App.aboutToQuit.connect(App.deleteLater)
    App.exec_()
    App.quit()

# Start web socket client and gui
if __name__ == "__main__":
    ws = websocket.WebSocketApp("ws://localhost/intent",
                              on_message = on_message,
                              on_error = on_error,
                              on_close = on_close,
                              on_open = on_open)
    wake = websocket.WebSocketApp("ws://localhost/wake-word",
                              on_message = on_Message,
                              on_error = on_Error,
                              on_close = on_Close,
                              on_open = on_Open)
    t1 = Thread(target = ws.run_forever)
    t2 = Thread(target = wake.run_forever)
    # start gui
    t3 = Thread(target = main_class())
    
    # starting threads 
    t1.start()
    t2.start()
    t3.start()
  
    # wait until all threads finish 
    t1.join()
    t2.join()
    t3.join()
    print ("Exiting Main Thread")

Answer 1

你有很多错误，但最突出的是：

• 您不能调用 on_message 回调，因为那是 WebSocketApp 任务。您要做的是每次调用 on_message 时执行您的逻辑。

• 不应在另一个线程中执行 GUI，因为 Qt 禁止它。

• 即便如此，您在另一个线程中执行 GUI 的尝试还是不成功，因为执行 t3 = Thread(target = main_class()) 与 f = main_class() t3 = Thread(target = f) 相同，也就是说，最终 GUI 在主线程中执行，阻塞了所有该行之后的代码。

逻辑是创建一个QObject，提供一种通过信号公开信息的方式（注意：回调在辅助线程中执行），然后在主线程中实现逻辑。

import json
import sys
import threading
from functools import cached_property

from PyQt5.QtCore import QObject, Qt, pyqtSignal
from PyQt5.QtWidgets import QApplication, QLabel, QVBoxLayout, QWidget

import websocket

# websocket.enableTrace(True)


class WebSocketClient(QObject):
    connected = pyqtSignal()
    disconnected = pyqtSignal()
    message_changed = pyqtSignal(str, name="messageChanged")
    error = pyqtSignal(str)

    def __init__(self, *, url, parent=None):
        super().__init__()
        self._url = url

    @cached_property
    def ws(self):
        return websocket.WebSocketApp(
            self._url,
            on_open=self._on_open,
            on_message=self._on_message,
            on_error=self._on_error,
            on_close=self._on_close,
        )

    def start(self):
        threading.Thread(target=self.ws.run_forever, daemon=True).start()

    def send(self, message):
        self.ws.send(message)

    def close(self):
        self.ws.close()

    def _on_open(self, ws):
        self.connected.emit()

    def _on_message(self, ws, message):
        self.message_changed.emit(message)

    def _on_error(self, ws, error):
        self.error.emit(str(error))

    def _on_close(self, ws):
        self.disconnected.emit()


class Widget(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)

        self.label = QLabel(alignment=Qt.AlignCenter)
        lay = QVBoxLayout(self)
        lay.addWidget(self.label)
        self.client.message_changed.connect(self.handle_message)
        self.client.start()
        self.resize(640, 480)

    @cached_property
    def client(self):
        return WebSocketClient(url="ws://localhost/intent")

    def handle_message(self, text):
        try:
            d = json.loads(text)
        except json.decoder.JSONDecodeError as e:
            print("error:", e)
        else:
            if "intent" in d:
                intent = d["intent"]
                if "name" in intent:
                    name = intent["name"]
                    self.label.setText(name)

    def closeEvent(self, event):
        super().closeEvent(event)
        self.client.close()


def main():
    app = QApplication(sys.argv)

    w = Widget()
    w.show()

    ret = app.exec_()
    sys.exit(ret)


if __name__ == "__main__":
    main()

更简单的解决方案是使用QtWebSockets。

import json
import sys
from functools import cached_property

from PyQt5.QtCore import QUrl, Qt, pyqtSignal
from PyQt5.QtWidgets import QApplication, QLabel, QVBoxLayout, QWidget
from PyQt5.QtWebSockets import QWebSocket


class Widget(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)

        self.label = QLabel(alignment=Qt.AlignCenter)
        lay = QVBoxLayout(self)
        lay.addWidget(self.label)
        self.client.textMessageReceived.connect(self.handle_message)
        self.client.open(QUrl("ws://localhost/intent"))
        self.resize(640, 480)

    @cached_property
    def client(self):
        return QWebSocket()

    def handle_message(self, text):
        try:
            d = json.loads(text)
        except json.decoder.JSONDecodeError as e:
            print("error:", e)
        else:
            if "intent" in d:
                intent = d["intent"]
                if "name" in intent:
                    name = intent["name"]
                    self.label.setText(name)

    def closeEvent(self, event):
        super().closeEvent(event)
        self.client.close()


def main():
    app = QApplication(sys.argv)

    w = Widget()
    w.show()

    ret = app.exec_()
    sys.exit(ret)


if __name__ == "__main__":
    main()