比urllib好用的requests

http://www.bsdmap.com/2013/01/13/python-requests/

Python标准库里提供了httplib以及urllib、urllib2，但是学习了好几次，都没有记住（下的功夫不够）。今天崔推荐了一个requests库，看了一下样例，几乎立即就会使用了，所以推荐给大家。
看官方是怎么描述这种情况的：
“Python’s standard urllib2 module provides most of the HTTP capabilities you need, but the API is thoroughly broken. It was built for a different time — and a different web. It requires an enormous amount of work (even method overrides) to perform the simplest of tasks.

Things shouldn’t be this way. Not in Python.”

http://docs.python-requests.org/en/latest/

可见urllib2确实不太容易使用。
常用功能罗列如下，以便查询。

# 0. 认证、状态码、header、编码、json
>>> r = requests.get('https://api.github.com/user', auth=('user', 'pass'))
>>> 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, ...}

# 1. 发起请求
import requests
URL="http://www.bsdmap.com/"
r = requests.get(URL)
r = requests.post(URL)
r = requests.put(URL)
r = requests.delete(URL)
r = requests.head(URL)
r = requests.options(URL)

# 2. 通过URL传递参数
>>> payload = {'key1': 'value1', 'key2': 'value2'}
>>> r = requests.get("http://httpbin.org/get", params=payload)
>>> print r.url
u'http://httpbin.org/get?key2=value2&key1=value1'

# 3. 返回内容
>>> import requests
>>> r = requests.get('https://github.com/timeline.json')
>>> r.text
'[{"repository":{"open_issues":0,"url":"https://github.com/...
>>> r.encoding
'utf-8'
>>> r.encoding = 'ISO-8859-1'

# 4. 二进制内容
You can also access the response body as bytes, for non-text requests:

>>> r.content
b'[{"repository":{"open_issues":0,"url":"https://github.com/...

The gzip and deflate transfer-encodings are automatically decoded for you.

For example, to create an image from binary data returned by a request,
 ou can use the following code:

>>> from PIL import Image
>>> from StringIO import StringIO
>>> i = Image.open(StringIO(r.content))

# 5. JSON
>>> import requests
>>> r = requests.get('https://github.com/timeline.json')
>>> r.json()
[{u'repository': {u'open_issues': 0, u'url': 'https://github.com/...

# 6. 超时
>>> requests.get('http://github.com', timeout=0.001)

# 7. 自定义header
>>> import json
>>> url = 'https://api.github.com/some/endpoint'
>>> payload = {'some': 'data'}
>>> headers = {'content-type': 'application/json'}

>>> r = requests.post(url, data=json.dumps(payload), headers=headers)

更多见官方文档：
http://docs.python-requests.org/en/latest/user/quickstart/
http://docs.python-requests.org/en/latest/user/advanced/#advanced