PyQT分段错误（有时候）

Question

我正在创建一个用于管理一些服务器的界面，基本功能包括重新启动服务等等。我使用QTCreator制作了此界面，并采用PyQT5进行编程。它正常工作（有时候）。但是有时候会出现Segmentation Fault或者QObject::connect: Cannot queue arguments of type 'QTextCursor'(Make sure 'QTextCursor' is registered using qRegisterMetaType().)的问题。

当我在MainWindow中点击restart_nginx时会发生这种情况，可能是线程管理方面的某些问题，这是我第一次使用PyQT/QT进行开发。

谢谢。

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from __future__ import unicode_literals

import paramiko
import threading

from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from ui_mainwindow import Ui_MainWindow

servers = {
    "Mars": "198.58.112.***",
    "Saturn": "198.58.116.***"
}

green = "rgb(83, 236, 17)"
default = "rgb(154, 154, 154)"
yellow = "yellow"
red = "red"
pw = 'pass'

def format_status(color):
    return "background-color: " + color + "; border: 1px solid black;"

class Worker(QObject):

    def __init__(self, ui, server, command=None, sudo=False, *args, **kwargs):
        QObject.__init__(self, *args, **kwargs)

        self.ssh = paramiko.SSHClient()
        self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())

        self.ui = ui
        self.command = command
        self.sudo = sudo
        self.server = server

    finished = pyqtSignal()

    @pyqtSlot()
    def execute(self):

        self.ui.status_restart_nginx.setStyleSheet(format_status(color=yellow))

        try:

            self.ssh.connect(self.server, username='hercules', password=pw)

        except paramiko.SSHException as e:

            self.ui.log.append("ERRO: Impossible to connect: %s", e)
            self.ui.status_restart_nginx.setStyleSheet(format_status(color=red))

        try:

            session = self.ssh.get_transport().open_session()
            session.get_pty()

            f = session.makefile()

            session.exec_command("ls -lh")

            #if self.sudo:
            #    session.send(pw + '\n')

            for line in f.readlines():
                self.ui.log.append(line)

            f.close()

            self.ssh.close()

            self.ui.status_restart_nginx.setStyleSheet(format_status(color=green))

        except Exception as e:
            self.ui.status_restart_nginx.setStyleSheet(format_status(color=red))
            print 'errinho: ', e

        self.finished.emit()

class MainWindow(QMainWindow, Ui_MainWindow):
    def __init__(self, parent=None, **kwargs):
        super(MainWindow, self).__init__(parent)
        self.setupUi(self)

        self.btn_restart_nginx.clicked.connect(self.restart_nginx)

        self.thread_worker = None
        self.obj_worker = None

    def create_worker(self, server, command=None, sudo=False):

        self.thread_worker = QThread(parent = self)
        self.obj_worker = Worker(ui = self, server = server, command = command, sudo = sudo)
        self.obj_worker.moveToThread(self.thread_worker)
        self.obj_worker.finished.connect(self.thread_worker.quit)
        self.thread_worker.started.connect(self.obj_worker.execute)
        self.thread_worker.start()

    def restart_nginx(self):

        self.status_restart_nginx.setStyleSheet(format_status(color=yellow))

        self.log.append("(Mars) Nginx: trying to restart front-end...")

        self.create_worker(servers["Mars"], command = "sudo service nginx restart", sudo = True)

if __name__=="__main__":

    from sys import argv, exit

    app = QApplication(argv)

    m = MainWindow()
    m.show()
    m.raise_()

    exit(app.exec_())

- Rafael Capucho

---

也许先谷歌一下错误信息 ;) - zhangxaochen

Answer 1

不要在工作线程中尝试更改GUI。只能从主GUI线程内更新GUI，不要将GUI元素的引用传递给工作线程。

在GUI线程和工作线程之间进行通信的最简单和最安全的方法是发出自定义信号。当以这种方式跨线程发出信号时，它们会排队，并且一旦控制返回到接收者的事件循环，插槽将在其线程中调用。

在PyQt中，当跨线程进行连接时，通常建议使用pyqtSlot装饰器，原因在此答案中概述。

- ekhumoro