python - PyQt 类不适用于第二次使用

Question

我正在使用 PyQt 完全加载一个页面(包括 JS)并使用 Beautiful Soup 获取它的内容。在第一次迭代时工作正常，但之后，它崩溃了。我对 Python 了解不多，对 PyQt 了解更少，因此非常欢迎任何帮助。

类借自here .

from PyQt4.QtCore import QUrl, SIGNAL
from PyQt4.QtGui import QApplication
from PyQt4.QtWebKit import QWebPage

from bs4 import BeautifulSoup
from bs4.dammit import UnicodeDammit
import sys
import signal


class Render(QWebPage):
    def __init__(self, url):
        self.app = QApplication(sys.argv)
        QWebPage.__init__(self)
        self.html = None
        signal.signal(signal.SIGINT, signal.SIG_DFL)
        self.connect(self, SIGNAL('loadFinished(bool)'), self._finished_loading)
        self.mainFrame().load(QUrl(url))
        self.app.exec_()

    def _finished_loading(self, result):
        self.html = self.mainFrame().toHtml()
        self.soup = BeautifulSoup(UnicodeDammit(self.html).unicode_markup)
        self.app.quit() 

###################################################################


l = ["http://www.google.com/?q=a", "http://www.google.com/?q=b", "http://www.google.com/?q=c"]

for page in l:
    soup = Render(page).soup
    print("# soup done: " + page)

Answer 1

该示例崩溃是因为 RenderPage 类试图为它尝试加载的每个 url 创建一个新的 QApplication 和事件循环。

相反，只应创建一个QApplication，并且QWebPage 子类应在处理完每个页面后加载一个新的url，而不是使用for 循环。

这是一个重写的例子，它应该做你想做的事:

import sys, signal
from bs4 import BeautifulSoup
from bs4.dammit import UnicodeDammit
from PyQt4 import QtCore, QtGui, QtWebKit

class WebPage(QtWebKit.QWebPage):
    def __init__(self):
        QtWebKit.QWebPage.__init__(self)
        self.mainFrame().loadFinished.connect(self.handleLoadFinished)

    def process(self, items):
        self._items = iter(items)
        self.fetchNext()

    def fetchNext(self):
        try:
            self._url, self._func = next(self._items)
            self.mainFrame().load(QtCore.QUrl(self._url))
        except StopIteration:
            return False
        return True

    def handleLoadFinished(self):
        self._func(self._url, self.mainFrame().toHtml())
        if not self.fetchNext():
            print('# processing complete')
            QtGui.qApp.quit()


def funcA(url, html):
    print('# processing:', url)
    # soup = BeautifulSoup(UnicodeDammit(html).unicode_markup)
    # do stuff with soup...

def funcB(url, html):
    print('# processing:', url)
    # soup = BeautifulSoup(UnicodeDammit(html).unicode_markup)
    # do stuff with soup...

if __name__ == '__main__':

    items = [
        ('http://stackoverflow.com', funcA),
        ('http://google.com', funcB),
        ]

    signal.signal(signal.SIGINT, signal.SIG_DFL)
    print('Press Ctrl+C to quit\n')
    app = QtGui.QApplication(sys.argv)
    webpage = WebPage()
    webpage.process(items)
    sys.exit(app.exec_())