title: how to set an X-Forwarded-For in http request in PyQt4
body: <p>I would like to know how can I add <code>X-Forwarded-For</code> paramet to my header.</p>
  
  <p>for example if I want to change user-uagent in my application, I would do some thing like this:</p>
  
  <pre><code>class MyBrowser(QWebPage):
      ''' Settings for the browser.'''
  
      def __init__(self):
          QWebPage.__init__(self)
  
      def userAgentForUrl(self, url):
          ''' Returns a User Agent that will be seen by the website. '''
          return "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.15 (KHTML, like Gecko) Chrome/24.0.1295.0 Safari/537.15"
  </code></pre>
  
  <p>and than I would do something like:</p>
  
  <pre><code>class Browser(QWebView):
      def __init__(self, user_info):
          QWebView.__init__(self)
          self.setPage(MyBrowser())
  </code></pre>