How do I rerender HTML PyQt4

问题

I have managed to use suggested code in order to render HTML from a webpage and then parse, find and use the text as wanted. I'm using PyQt4. However, the webpage I am interested in is updated frequently and I want to rerender the page and check the updated HTML for new info.

I thus have a loop in my pythonscript so that I sort of start all over again. However, this makes the program crash. I have searched the net and found out that this is to be expected, but I have not found any suggestion on how to do it correctly. It must be simple, I guess?

from PyQt4.QtGui import *

from PyQt4.QtCore import *

from PyQt4.QtWebKit import *


class Render (QWebPage):

    def __init__(self, url):
        self.app = QApplication(sys.argv)
        QWebPage.__init__(self)
        self.loadFinished.connect(self._loadFinished)
        self.mainFrame().load(QUrl(url))
        self.app.exec_()
    def _loadFinished(self, result):
        self.frame = self.mainFrame()
        self.app.quit()

r = Render(url)  

html = r.frame.toHtml()

S,o when I hit r=Render(url) the second time, it crashes. S,o I am looking for something like r = Rerender(url).

As you might guess, I am not much of a programmer, and I usually get by by stealing code I barely understand. But this is the first time I can't find an answer, so I thought I should ask a question myself.

I hope my question is clear enough and that someone has the answer.

回答1:

Simple demo (adapt to taste):

import sys, signal
from PyQt4 import QtCore, QtGui, QtWebKit

class WebPage(QtWebKit.QWebPage):
    def __init__(self, url):
        super(WebPage, self).__init__()
        self.url = url
        self.mainFrame().loadFinished.connect(self.handleLoadFinished)
        self.refresh()

    def refresh(self):
        self.mainFrame().load(QtCore.QUrl(self.url))

    def handleLoadFinished(self):
        print('Loaded:', self.mainFrame().url().toString())
        # do stuff with html ...
        print('Reloading in 3 seconds...\n')
        QtCore.QTimer.singleShot(2000, self.refresh)

if __name__ == '__main__':

    signal.signal(signal.SIGINT, signal.SIG_DFL)
    app = QtGui.QApplication(sys.argv)
    webpage = WebPage('http://en.wikipedia.org/')
    print('Press Ctrl+C to quit\n')
    sys.exit(app.exec_())

来源：https://stackoverflow.com/questions/33697952/how-do-i-rerender-html-pyqt4

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