Requests库

Requests 是使用Apache2 Licensed 许可证的HTTP 库。用Python 编写。
Requests 使用的是urllib3，因此继承了它的所有特性。Requests 支持HTTP 连接保持和连接池，支持使用cookie 保持会话，支持文件上传，支持自动确定响应内容的编码，支持国际化的URL 和POST 数据自动编码。

1.Requests安装

下载地址：https://pypi.python.org/pypi/requests/

官方网站：http://docs.python-requests.org/en/master/

中文文档：http://cn.python-requests.org/zh_CN/latest/

2.Demo

>>> r = requests.get('https://api.github.com/user', auth=('user', 'psw'))
>>> r.status_code
200
>>> r.headers['content-type']
'application/json; charset=utf8'
>>> r.encoding
'utf-8'
>>> r.text
u'{"type":"User"...'
>>> r.json()
{u'private_gists': 419, u'total_private_repos': 77, ...}

其中auth=('user', 'psw')为github系统注册的账号和密码

3.Post请求模拟登录

import requests
url1 = 'http://www.exanple.com/login'#登录地址
url2 = "http://www.example.com/main"#需要登录才能访问的地址
data={"user":"user","password":"pass"}
headers = { "Accept":"text/html,application/xhtml+xml,application/xml;",
            "Accept-Encoding":"gzip",
            "Accept-Language":"zh-CN,zh;q=0.8",
            "Referer":"http://www.example.com/",
            "User-Agent":"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.90 Safari/537.36"
            }
res1 = requests.post(url1, data=data, headers=headers)
res2 = requests.get(url2, cookies=res1.cookies, headers=headers)

print(res2.content)#获得二进制响应内容
print(res2.raw)#获得原始响应内容,需要stream=True
print(res2.raw.read(50))
print(type(res2.text))#返回解码成unicode的内容
print(res2.url)
print(res2.history)#追踪重定向
print(res2.cookies)
print(res2.cookies['example_cookie_name'])
print(res2.headers)
print(res2.headers['Content-Type'])
print(res2.headers.get('content-type'))
print(res2.json)#讲返回内容编码为json
print(res2.encoding)#返回内容编码
print(res2.status_code)#返回http状态码
print(res2.raise_for_status())#返回错误状态码

4.使用Session()对象的写法

import requests
s = requests.Session()
url1 = 'http://www.exanple.com/login'#登录地址
url2 = "http://www.example.com/main"#需要登录才能访问的页面地址
data={"user":"user","password":"pass"}
headers = { "Accept":"text/html,application/xhtml+xml,application/xml;",
            "Accept-Encoding":"gzip",
            "Accept-Language":"zh-CN,zh;q=0.8",
            "Referer":"http://www.example.com/",
            "User-Agent":"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.90 Safari/537.36"
            }
res1 = s.post(url1, data=data)
res2 = s.post(url2)
print(res2.content)