CODEWITHSUNDEEP
pythonpysideqtcpsocket
mikanim
mikanim

Reputation: 439

Python QtNetwork.QTcpSocket.readAll() and QtNetwork.QTcpSocket.write() not working

I'm doing a simple socket connection and the read.All() and write() are not giving me anything back. 

import PySide.QtNetwork as Network
import PySide.QtCore as Core

proxyAddress = '127.0.0.1'
proxyPort = 1025
tcpSocket = Network.QTcpSocket()
tcpSocket.connectToHost(proxyAddress, proxyPort)

tcpSocket.state() gives 

"PySide.QtNetwork.QAbstractSocket.SocketState.ConnectingState"

When I then try to send something, I get this back:

tcpSocket.write("Hello")
5L

And for readAll():

tcpSocket.readAll()
PySide.QtCore.QByteArray('')

Oh and to disconnect I try:

tcpSocket.disconnectFromHost()

and it comes back with the next line to write as if it was successful in disconnecting but when I check the state:

tcpSocket.state()
"PySide.QtNetwork.QAbstractSocket.SocketState.ConnectingState"

Any help is appreciated.

Upvotes: 0

Views: 1813

Answers (1)

eyllanesc
eyllanesc

Reputation: 244132

First of all the state that signals is ConnectingState that indicates that the connection has not been made so it is not correct to perform any task at that moment, you must wait for the status to be ConnectedState. On the other hand, the port you point out is probably being used by another application since it is a small number that are usually reserved for another task. In the next part I show an example of a server and a client (first launch the server and then you can launch the number of clients you want.). Finally in Qt the tasks should not be performed synchronously but through signals since the Qt event-loop needs to update internal and external variables states.

server.py

import uuid
from PySide import QtCore, QtNetwork

class ServerManager(QtCore.QObject):
    def __init__(self, parent=None):
        super(ServerManager, self).__init__(parent)
        self._server = QtNetwork.QTcpServer(self)
        self._server.newConnection.connect(self.on_newConnection)
        self._clients = {}

    def launch(self, address=QtNetwork.QHostAddress.Any, port=9999):
        return self._server.listen(QtNetwork.QHostAddress(address), port)

    @QtCore.Slot()
    def on_newConnection(self):
        socket = self._server.nextPendingConnection()
        socket.readyRead.connect(self.on_readyRead)
        if socket not in self._clients:
            self._clients[socket] = uuid.uuid4()

    @QtCore.Slot()
    def on_readyRead(self):
        socket = self.sender()
        resp = socket.readAll()
        code = self._clients[socket]
        print("From[{}]- message: {}".format(code, resp))
        socket.write("Server: " + str(resp)[::-1])

if __name__ == '__main__':
    import sys
    import signal
    signal.signal(signal.SIGINT, signal.SIG_DFL)
    app = QtCore.QCoreApplication(sys.argv)

    address = '127.0.0.1'
    port = 9000
    server = ServerManager()
    if not server.launch(address, port):
        sys.exit(-1)
    sys.exit(app.exec_())

client.py

from PySide import QtCore, QtNetwork

class ClientManager(QtCore.QObject):
    def __init__(self, parent=None):
        super(ClientManager, self).__init__(parent)
        self._socket = QtNetwork.QTcpSocket(self)
        self._socket.stateChanged.connect(self.on_stateChanged)
        self._socket.readyRead.connect(self.on_readyRead)
        self._timer = QtCore.QTimer(self, interval=1000)
        self._timer.timeout.connect(self.sendMessage)

    def launch(self, address=QtNetwork.QHostAddress.Any, port=9999):
        return self._socket.connectToHost(QtNetwork.QHostAddress(address), port)

    @QtCore.Slot(QtNetwork.QAbstractSocket.SocketState)
    def on_stateChanged(self, state):
        if state == QtNetwork.QAbstractSocket.ConnectedState:
            self._timer.start()
            print("connected")
        elif state == QtNetwork.QAbstractSocket.UnconnectedState:
            print("disconnected")
            QtCore.QCoreApplication.quit()

    @QtCore.Slot()
    def sendMessage(self):
        if self._socket.state() == QtNetwork.QAbstractSocket.ConnectedState:
            msg = QtCore.QDateTime.currentDateTime().toString()
            self._socket.write(msg) 

    @QtCore.Slot()
    def on_readyRead(self):
        print("Response: ", self._socket.readAll())

if __name__ == '__main__':
    import sys
    import signal
    signal.signal(signal.SIGINT, signal.SIG_DFL)
    app = QtCore.QCoreApplication(sys.argv)
    address = '127.0.0.1'
    port = 9000
    server = ClientManager()
    server.launch(address, port)
    sys.exit(app.exec_())

Upvotes: 1

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