本代码演示了python的urllib2模块如何使用代理，以及需要登录验证的proxy

# The proxy address and port:
proxy_info = { 'host' : 'proxy.myisp.com',
               'port' : 3128
             }
 
# We create a handler for the proxy
proxy_support = urllib2.ProxyHandler({"http" : "http://%(host)s:%(port)d" % proxy_info})
 
# We create an opener which uses this handler:
opener = urllib2.build_opener(proxy_support)
 
# Then we install this opener as the default opener for urllib2:
urllib2.install_opener(opener)
 
# Now we can send our HTTP request:
htmlpage = urllib2.urlopen("http://sebsauvage.net/").read(200000)
 
#如果代理需要验证
proxy_info = { 'host' : 'proxy.myisp.com',
               'port' : 3128,
               'user' : 'John Doe',
               'pass' : 'mysecret007'
             }
proxy_support = urllib2.ProxyHandler({"http" : "http://%(user)s:%(pass)s@%(host)s:%(port)d" % proxy_info})
opener = urllib2.build_opener(proxy_support)
urllib2.install_opener(opener)
htmlpage = urllib2.urlopen("http://sebsauvage.net/").read(200000)