how to load multiple pages one by one in QWebPage - qt

Question

I am trying to crawl news article pages for comments. After some research I found that mostly websites use an iframe for it. I want to get the "src" of the iframe. I am using QtWebKit in Python using PySide. It is actually working but just once. It is not loading other webpages. I am using the following code:
import sys
import pymysql
from PySide.QtGui import *
from PySide.QtCore import *
from PySide.QtWebKit import *
from pprint import pprint
from bs4 import BeautifulSoup
class Render(QWebPage):
def __init__(self, url):
try:
self.app = QApplication(sys.argv)
except RuntimeError:
self.app = QCoreApplication.instance()
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()
def visit(url):
r = Render(url)
p = r.frame.toHtml()
f_url = str(r.frame.url().toString())
return p
def is_comment_url(url):
lower_url = url.lower()
n = lower_url.find("comment")
if n>0:
return True
else:
return False
with open("urls.txt") as f:
content = f.read().splitlines()
list_of_urls = []
for url in content:
page = visit(url)
soup = BeautifulSoup(page)
for tag in soup.findAll('iframe', src=True):
link = tag['src']
if is_comment_url(link):
print(link)
list_of_urls += link
pprint(list_of_urls)
But the issue is it works only for single iteration and gets stuck.
Also is there any way to save a web page as it is as displayed by the browser (after executing all the javascript etc.)