How to use qtwebkit in python threads?

Question

I'm trying to parse webpages generated by js with qtwebkit, I found an example of how to get page source:

import sys
from PySide.QtGui import *
from PySide.QtCore import *
from PySide.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()
url = 'http://www.thesite.gov/search'
r = Render(url)
html = r.frame.toHtml()

But i don't know how to make it work in threads. So, how to do this and if it's not possible - is there another fast way to get wepages generated by js?

andrean · Accepted Answer · 2012-10-13 10:07:04Z

3

Given QT's async nature, the QtWebkit methods are non-blocking as well, so there is no point running them in threads. You can start them parallelly like this:

from functools import partial

from PySide.QtCore import QUrl
from PySide.QtGui import QApplication
from PySide.QtWebKit import QWebView, QWebSettings


TARGET_URLS = (
    'http://stackoverflow.com',
    'http://github.com',
    'http://bitbucket.org',
    'http://news.ycombinator.com',
    'http://slashdot.org',
    'http://www.reddit.com',
    'http://www.dzone.com',
    'http://www.ideone.com',
    'http://jsfiddle.net',
)


class Crawler(object):

    def __init__(self, app):
        self.app = app
        self.results = dict()
        self.browsers = dict()

    def _load_finished(self, browser_id, ok):
        print ok, browser_id
        web_view, _flag = self.browsers[browser_id]
        self.browsers[browser_id] = (web_view, True)

        frame = web_view.page().mainFrame()
        self.results[frame.url()] = frame.toHtml()

        web_view.loadFinished.disconnect()
        web_view.stop()

        if all([closed for bid, closed in self.browsers.values()]):
            print 'all finished'
            self.app.quit()

    def start(self, urls):
        for browser_id, url in enumerate(urls):
            web_view = QWebView()
            web_view.settings().setAttribute(QWebSettings.AutoLoadImages,
                                             False)
            loaded = partial(self._load_finished, browser_id)
            web_view.loadFinished.connect(loaded)
            web_view.load(QUrl(url))
            self.browsers[browser_id] = (web_view, False)


if __name__ == '__main__':
    app = QApplication([])
    crawler = Crawler(app)
    crawler.start(TARGET_URLS)
    app.exec_()
    print 'got:', crawler.results.keys()

answered Oct 13, 2012 at 10:07

andrean

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8 Comments

user1179442 Over a year ago

How to parse web page(html +js) with PySide or PtQt? These codes seems that can't parse JS

andrean Over a year ago

@user1179442: It can be enabled through: QWebView().settings().setAttribute(QWebSettings.JavascriptEnabled, False)

user1179442 Over a year ago

Thanks for your info. But the 2nd argument should be "True" :)

andrean Over a year ago

@user1179442 indeed, sorry about that :) (copy/paste)

user1179442 Over a year ago

I've another question that sometimes the result looks didn't parsed all js. Is it due to asynchronous ?

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