Python QtWebKit第二个链接未下载

Question

我正在尝试下载这两个链接的内容。第一个链接正常工作，内容下载为html文件。但是没有下载第二个链接（文本文件）的内容。请帮帮我进行。

这是我的代码：

from PySide.QtCore import *
from PySide.QtGui import *
from PySide.QtWebKit import *
import sys
import codecs

class Downloader(QObject):
    # To be emitted when every items are downloaded
    done = Signal()

    def __init__(self, urlList, parent = None):
        super(Downloader, self).__init__(parent)
        self.urlList = urlList
        self.counter = 0        
        # As you probably don't need to display the page
        # you can use QWebPage instead of QWebView
        self.page = QWebPage(self)      
        self.page.loadFinished.connect(self.save)
        self.startNext()

    def currentUrl(self):
        return self.urlList[self.counter][0]

    def currentFilename(self):
        return self.urlList[self.counter][1]

    def startNext(self):
        print "Downloading %s..."%self.currentUrl()
        self.page.mainFrame().load(self.currentUrl())

    def save(self, ok):
        if ok:            
            data = self.page.mainFrame().toHtml()
            with codecs.open(self.currentFilename(), encoding="utf-8", mode="w") as f:
                f.write(data)
            print "Saving %s to %s."%(self.currentUrl(), self.currentFilename())            
        else:
            print "Error while downloading %s\nSkipping."%self.currentUrl()
        self.counter += 1
        if self.counter < len(self.urlList):            
            self.startNext()
        else:
            self.done.emit()

urlList = [("http://www.nsf.gov/awardsearch/simpleSearchResult?queryText=8","nsf.html"), 
("http://www.nsf.gov/awardsearch/ExportResultServlet?exportType=txt","a.txt")] 

app = QApplication(sys.argv)
downloader = Downloader(urlList)
# Quit when done
downloader.done.connect(app.quit)

# To view the pages
web = QWebView()
# To prevent user action that would interrupt the current page loading
web.setDisabled(True) 
web.setPage(downloader.page)
web.show()

sys.exit(app.exec_())