how to detect the character encoding in a web page ?

[iMath]

在 2012年12月24日星期一UTC+8上午8时34分47秒，iMath写道：
> how to detect the character encoding  in a web page ?
> 
> such as this page 
> 
> 
> 
> http://python.org/

I found PyQt’s QtextStream can  very accurately detect the character encoding in a web page . 
even for this bad page 
http://www.qnwz.cn/html/yinlegushihui/magazine/2013/0524/425731.html
chardet and beautiful soup failed ,but QtextStream can get the right result . 

here is my code 

from PyQt4.QtCore import * 
from PyQt4.QtGui import * 
from PyQt4.QtNetwork  import * 
import sys 
def slotSourceDownloaded(reply): 
    redirctLocation=reply.header(QNetworkRequest.LocationHeader) 
    redirctLocationUrl=reply.url() if not redirctLocation else redirctLocation 
    print(redirctLocationUrl) 
  
    if (reply.error()!= QNetworkReply.NoError): 
        print('11111111', reply.errorString()) 
        return 
  
    content=QTextStream(reply).readAll() 
    if content=='': 
        print('---------', 'cannot find any resource !') 
        return 
  
    print(content) 
      
    reply.deleteLater() 
    qApp.quit() 
  
  
if __name__ == '__main__': 
    app =QCoreApplication(sys.argv) 
    manager=QNetworkAccessManager () 
    url =input('input url :') 
    request=QNetworkRequest (QUrl.fromEncoded(QUrl.fromUserInput(url).toEncoded())) 
    request.setRawHeader("User-Agent" ,'Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.17 (KHTML, like Gecko) Chrome/24.0.1312.57 Safari/537.17 SE 2.X MetaSr 1.0') 
    manager.get(request) 
    manager.finished.connect(slotSourceDownloaded) 
    sys.exit(app.exec_())