python requests用法总结
requests是一个很实用的Python HTTP客户端库，编写爬虫和测试服务器响应数据时经常会用到。可以说，Requests 完全满足如今网络的需求
本文全部来源于官方文档:
http://docs.python-requests.org/en/master/
http://cn.python-requests.org/zh_CN/latest/
安装方式一般采用pip install requests。其它安装方式参考官方文档
导入模块： import requests
一、GET请求
r = requests.get('http://httpbin.org/get')
传参
>>> payload = {'key1': 'value1', 'key2': 'value2', 'key3': None}
>>> r = requests.get('http://httpbin.org/get', params=payload)
http://httpbin.org/get?key2=value2&key1=value1
Note that any dictionary key whose value is None will not be added to the URL's query string.
参数也可以传递列表
>>> payload = {'key1': 'value1', 'key2': ['value2', 'value3']}
>>> r = requests.get('http://httpbin.org/get', params=payload)
>>> print(r.url)
http://httpbin.org/get?key1=value1&key2=value2&key2=value3
r.text 返回headers中的编码解析的结果，可以通过r.encoding = 'gbk'来变更解码方式
r.content 返回二进制结果
r.json() 返回JSON格式，可能抛出异常
r.status_code
r.raw 返回原始socket respons，需要加参数stream=True
>>> r = requests.get('https://api.github.com/events', stream=True)
>>> r.raw
<requests.packages.urllib3.response.HTTPResponse object at 0x101194810>
>>> r.raw.read(10)
'\x1f\x8b\x08\x00\x00\x00\x00\x00\x00\x03'
将结果保存到文件，利用r.iter_content()
with open(filename, 'wb') as fd:
for chunk in r.iter_content(chunk_size):
fd.write(chunk)
传递headers
>>> headers = {'user-agent': 'my-app/0.0.1'}
>>> r = requests.get(url, headers=headers)
传递cookies
>>> url = 'http://httpbin.org/cookies'
>>> r = requests.get(url, cookies=dict(cookies_are='working'))
>>> r.text
'{"cookies": {"cookies_are": "working"}}'
二、POST请求
传递表单
r = requests.post('http://httpbin.org/post', data = {'key':'value'})
通常，你想要发送一些编码为表单形式的数据—非常像一个HTML表单。 要实现这个，只需简单地传递一个字典给 data 参数。你的数据字典在发出请求时会自动编码为表单形式:
>>> payload = {'key1': 'value1', 'key2': 'value2'}
>>> r = requests.post("http://httpbin.org/post", data=payload)
>>> print(r.text)
{
...
"form": {
"key2": "value2",
"key1": "value1"
},
...
}
很多时候你想要发送的数据并非编码为表单形式的。如果你传递一个 string 而不是一个dict ，那么数据会被直接发布出去。
>>> url = 'https://api.github.com/some/endpoint'
>>> payload = {'some': 'data'}
>>> r = requests.post(url, data=json.dumps(payload))
或者
>>> r = requests.post(url, json=payload)
传递文件
url = 'http://httpbin.org/post'
>>> files = {'file': open('report.xls', 'rb')}
>>> r = requests.post(url, files=files)
配置files，filename, content_type and headers
files = {'file': ('report.xls', open('report.xls', 'rb'), 'application/vnd.ms-excel', {'Expires': '0'})}
files = {'file': ('report.csv', 'some,data,to,send\nanother,row,to,send\n')}
响应
r.status_code
r.heards
r.cookies
跳转
By default Requests will perform location redirection for all verbs except HEAD.
>>> r = requests.get('http://httpbin.org/cookies/set?k2=v2&k1=v1')
>>> r.url
'http://httpbin.org/cookies'
>>> r.status_code
200
>>> r.history
[<Response [302]>]
If you're using HEAD, you can enable redirection as well:
r = requests.head('http://httpbin.org/cookies/set?k2=v2&k1=v1',allow_redirects=True)
You can tell Requests to stop waiting for a response after a given number of seconds with the timeoutparameter:
requests.get('http://github.com', timeout=0.001)
参考文章：http://www.cnblogs.com/lilinwei340/p/6417689.html
