用fiddler过滤出地址和需要的参数

先用cookielib获取cookie，再用获取到的cookie，进入需要登录的网站。
# -*- coding: utf-8 -*-

# !/usr/bin/python

import urllib2
import urllib
import cookielib
import re
auth_url = 'http://www.nowamagic.net/'
home_url = 'http://www.nowamagic.net/';
# 登陆用户名和密码
data={
   "username":"nowamagic",
   "password":"pass"
}
# urllib进行编码
post_data=urllib.urlencode(data)
# 发送头信息

headers ={

   "Host":"www.nowamagic.net",
"Referer": "http://www.nowamagic.net"
}
# 初始化一个CookieJar来处理Cookie

cookieJar=cookielib.CookieJar()
# 实例化一个全局opener

opener=urllib2.build_opener(urllib2.HTTPCookieProcessor(cookieJar))

# 获取cookie
req=urllib2.Request(auth_url,post_data,headers)
result = opener.open(req)
# 访问主页 自动带着cookie信息
result = opener.open(home_url)
# 显示结果
print result.read()

再附带几个示例程序：
1. 使用已有的cookie访问网站
import cookielib, urllib2

ckjar = cookielib.MozillaCookieJar(os.path.join('C:\Documents and Settings\tom\Application 
Data\Mozilla\Firefox\Profiles\h5m61j1i.default', 'cookies.txt'))
req = urllib2.Request(url, postdata, header)

req.add_header('User-Agent', \
   'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)')

opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(ckjar) )

f = opener.open(req)
htm = f.read()
f.close()

2. 访问网站获得cookie，并把获得的cookie保存在cookie文件中
import cookielib, urllib2

req = urllib2.Request(url, postdata, header)
req.add_header('User-Agent', \
   'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)')

ckjar = cookielib.MozillaCookieJar(filename)
ckproc = urllib2.HTTPCookieProcessor(ckjar)

opener = urllib2.build_opener(ckproc)

f = opener.open(req)
htm = f.read()
f.close()

ckjar.save(ignore_discard=True, ignore_expires=True)
3. 使用指定的参数生成cookie,并用这个cookie访问网站
import cookielib, urllib2

cookiejar = cookielib.CookieJar()
urlOpener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cookiejar))
values = {'redirect':", 'email':'[email protected]',
      'password':'password', 'rememberme':", 'submit':'OK, Let Me In!'}
data = urllib.urlencode(values)

request = urllib2.Request(url, data)
url = urlOpener.open(request)
print url.info()
page = url.read()

request = urllib2.Request(url)
url = urlOpener.open(request)
page = url.read()
print page