[python]用urllib2设置代理访问网页

#!/usr/bin/env python
import urllib2

# change followings before use
user = 'foo'
passwd = 'bar'
proxyserver = '1.2.3.4:5'
url   = 'http://www.google.com/'

def proxy1():
    # work
    proxy = 'http://%s:%s@%s' % (user, passwd, proxyserver)
    opener = urllib2.build_opener( urllib2.ProxyHandler({'http':proxy}) )
    urllib2.install_opener( opener )

    sContent = urllib2.urlopen(url)
    print sContent.read()

def proxy2():
    # work for someone, but not for me
    passmgr = urllib2.HTTPPasswordMgrWithDefaultRealm()
    passmgr.add_password('realm', proxyserver, user, passwd)
    authinfo = urllib2.ProxyBasicAuthHandler(passmgr)

    proxy = 'http://%s' % proxyserver
    opener = urllib2.build_opener(urllib2.ProxyHandler( {'http':proxy} ), authinfo)
    urllib2.install_opener(opener)

    sContent = urllib2.urlopen(url)
    print sContent.read()

def proxy3():
    # work for someone, but not for me
    authinfo = urllib2.HTTPBasicAuthHandler()
    authinfo.add_password('realm', proxyserver, user, passwd)
    
    proxy = 'http://%s' % proxyserver
    opener = urllib2.build_opener(urllib2.ProxyHandler( {'http':proxy} ), authinfo)
    urllib2.install_opener(opener)
    
    sContent = urllib2.urlopen(url)
    print sContent.read()

 在linux系统中，如果urllib2设置的代理不好用可以试试环境变量：
export http_proxy='protocol://user:passwd@proxyserver:port'
export https_proxy='protocol://user:passwd@proxyserver:port'
 比如通过代理上传appengine文件，其SDK中的rpc不提供代理设置，就可以用这招。