pyqt5 qnetworkreply在信号处理程序中停止更新连续响应

Question

我试图连续从该服务器获取帧：

def get_feed():
    while True:
        time.sleep(0.06)
        buffer = get_shot()
        buffer = buffer.tobytes()
        yield (b'--frame\r\n'
               b'Content-Type: image/jpeg\r\n'
               b'Content-Length: ' + str(len(buffer)).encode() + '\r\n\r\n' + 
               buffer + b'\r\n')
               
               
@app.route('/', methods=['GET'])
def index():
    return Response(get_feed(), mimetype='multipart/x-mixed-replace; boundary=frame')

为此，我使用以下代码：

class ExampleApp(QtWidgets.QMainWindow, test.Ui_MainWindow):
    def __init__(self, parent=None):
        super(ExampleApp, self).__init__(parent)
        self.setupUi(self)
        
        self._source_url = QUrl("*link_here*")
        self._image_request = QNetworkRequest(self._source_url)
        self._network_manager = QNetworkAccessManager()
        self._image_reply = self._network_manager.get(self._image_request)
        ...

        self.frameTimer = QTimer(self)
        self.timeBetweenFrames = 1
        self.timeBetweenReads = 0.06
        self.frameTimer.timeout.connect(self.updateFrame)
        self.frameTimer.start(self.timeBetweenFrames)
        ...

    def updateFrame(self):
        # Get how many bytes do I need to read for the frame
        content_length = 0
        buff = self._image_reply.readAll()
        frameSizeAddress = buff.lastIndexOf(b'Content-Length:') + len(b'Content-Length: ')
        frameSizeEndAddress = buff[frameSizeAddress:].indexOf(b'\r\n')
        
        if frameSizeAddress == -1 or frameSizeEndAddress == -1:
            self.frameTimer.start(self.timeBetweenFrames)
            return
        
        frameSize = int(str(buff[frameSizeAddress:frameSizeAddress+frameSizeEndAddress], 'utf-8'))
        frameBegin = frameSizeAddress + frameSizeEndAddress + 4
        
        imageBuffer = buff[frameBegin:frameBegin+frameSize]
        readenBytes = len(imageBuffer)
        
        # If the image came partially
        while(readenBytes < frameSize):
            time.sleep(self.timeBetweenReads)
            buff = self._image_reply.read(frameSize-readenBytes)
            imageBuffer += buff[:frameSize-readenBytes]
            readenBytes = len(imageBuffer)
            print(len(buff))

问题来了。如果图像部分出现，则永远不会被读取。最后一次打印总是给出 0。

如果在第一次读取期间使用 read(1024) 而不是 readAll()

content_length = 0
buff = self._image_reply.readAll()

那么一切正常，但如果帧速度更快，那么应用程序会读取它们：它们开始堆叠，并且馈送和显示图像之间的延迟变得越来越大。

对我来说，QNetworkReply 在信号处理程序中时似乎不会更新，因此服务器不会在其中写入新字节。

我该如何解决这个问题？