How do I rerender HTML PyQt4 - html

Question

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.

Answer 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_())