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Python Requests库:HTTP for Humans

Python标准库中用来处理HTTP的模块是urllib2,不过其中的API太零碎了,requests是更简单更人性化的第三方库。

用pip下载:

pip install requests

或者git:

git clone git://github.com/kennethreitz/requests.git

发送请求:

GET方法

>>> import requests>>> r = requests.get(‘https://api.github.com/events‘)

POST方法:

>>> r = requests.post("http://httpbin.org/post")

也可以使用其它方法:

>>> r = requests.put("http://httpbin.org/put")>>> r = requests.delete("http://httpbin.org/delete")>>> r = requests.head("http://httpbin.org/get")>>> r = requests.options("http://httpbin.org/get")

也可以将请求方法放在参数中:

>>> import requests>>> req = requests.request(‘GET‘, ‘http://httpbin.org/get‘)

传递参数或上传文件:

1.如果要将参数放在url中传递,使用params参数,可以是字典或者字符串:

>>> payload = {‘key1‘: ‘value1‘, ‘key2‘: ‘value2‘}>>> r = requests.get("http://httpbin.org/get", params=payload)>>> r.urlu‘http://httpbin.org/get?key2=value2&key1=value1‘

2.如果要将参数放在request body中传递,使用data参数,可以是字典,字符串或者是类文件对象。

使用字典时将发送form-encoded data:

>>> payload = {‘key1‘: ‘value1‘, ‘key2‘: ‘value2‘}>>> r = requests.post("http://httpbin.org/post", data=http://www.mamicode.com/payload)"form": {    "key2": "value2",    "key1": "value1"  },  ...}

使用字符串时将直接发送数据:

>>> import json>>> url = ‘https://api.github.com/some/endpoint‘>>> payload = {‘some‘: ‘data‘}>>> r = requests.post(url, data=http://www.mamicode.com/json.dumps(payload))

3.如果要上传文件,可以使用file参数发送Multipart-encoded数据,file参数是{ ‘name‘: file-like-objects}格式的字典 (or {‘name‘:(‘filename‘, fileobj)}) :

>>> url = ‘http://httpbin.org/post‘>>> files = {‘file‘: open(‘report.xls‘, ‘rb‘)}>>> r = requests.post(url, files=files)>>> r.text{  ...  "files": {    "file": "<censored...binary...data>"  },  ...}

也可以明确设置filename, content_type and headers:

>>> url = ‘http://httpbin.org/post‘>>> files = {‘file‘: (‘report.xls‘, open(‘report.xls‘, ‘rb‘), ‘application/vnd.ms-excel‘, {‘Expires‘: ‘0‘})}>>> r = requests.post(url, files=files)>>> print r.text{  "args": {},   "data": "",   "files": {    "file": "1\t2\r\n"  },   "form": {},   "headers": {    "Content-Type": "multipart/form-data; boundary=e0f9ff1303b841498ae53a903f27e565",     "Host": "httpbin.org",     "User-Agent": "python-requests/2.2.1 CPython/2.7.3 Windows/7",   },   "url": "http://httpbin.org/post"}

设置Headers

>>> import json>>> url = ‘https://api.github.com/some/endpoint‘>>> payload = {‘some‘: ‘data‘}>>> headers = {‘content-type‘: ‘application/json‘}>>> r = requests.post(url, data=http://www.mamicode.com/json.dumps(payload), headers=headers)

Response对象:

 获取unicode字符串,会自动根据响应头部的字符编码(r.encoding)进行解码,当然也可以自己设定r.encoding:

>>> r = requests.get(‘https://github.com/timeline.json‘)>>> r.textu‘{"message":"Hello there, wayfaring stranger...

获取bytes字符串,会自动解码gzip和deflate数据:

>>> r.content‘{"message":"Hello there, wayfaring stranger. ..

要存储web图片,可以:

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

可以解码json对象:

>>> r.json(){u‘documentation_url‘: u‘https://developer...

返回raw response,需要在requests请求中将stream设为True:

>>> r = requests.get(‘https://github.com/timeline.json‘, 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‘

当然,更好的方法是迭代的处理数据:

with open(filename, ‘wb‘) as fd:    for chunk in r.iter_content(chunk_size):        fd.write(chunk)

获取响应代码:

>>> r = requests.get(‘http://httpbin.org/get‘)>>> r.status_code200

获取响应headers:

>>> r.headers{    ‘content-encoding‘: ‘gzip‘,    ‘transfer-encoding‘: ‘chunked‘,    ‘connection‘: ‘close‘,    ‘server‘: ‘nginx/1.0.4‘,    ‘x-runtime‘: ‘148ms‘,    ‘etag‘: ‘"e1ca502697e5c9317743dc078f67693f"‘,    ‘content-type‘: ‘application/json‘}

Cookie

获取cookie,返回CookieJar对象:

>>> url = ‘http://www.baidu.com‘>>> r = requests.get(url)>>> r.cookies

将CookieJar转为字典:

>>> requests.utils.dict_from_cookiejar(r.cookies){‘BAIDUID‘: ‘84722199DF8EDC372D549EC56CA1A0E2:FG=1‘, ‘BD_HOME‘: ‘0‘, ‘BDSVRTM‘: ‘0‘}

将字典转为CookieJar:

requests.utils.cookiejar_from_dict(cookie_dict, cookiejar=None, overwrite=True)

上传自己设置的cookie,使用cookies参数,可以是字典或者CookieJar对象:

>>> url = ‘http://httpbin.org/cookies‘>>> cookies = dict(cookies_are=‘working‘)>>> r = requests.get(url, cookies=cookies)>>> r.text‘{"cookies": {"cookies_are": "working"}}‘

如果需要在会话中保留cookie,需要用到后面要说的Session。

Redirection and History

可以用history属性来追踪redirection

>>> r = requests.get(‘http://github.com‘)>>> r.url‘https://github.com/‘>>> r.status_code200>>> r.history[<Response [301]>]

Session

要在会话中保留状态,可以使用request.Session()。

Session可以使用get,post等方法,返回的cookie等会在下一次访问时自动保留:

>>> import requests>>> s = requests.Session()>>> s.get(‘http://httpbin.org/get‘)200

也可以自己设置headers,cookies:

>>> import requests>>> s = requests.Session()>>> s.headers={...}

验证

Basic Authentication

>>> from requests.auth import HTTPBasicAuth>>> requests.get(‘https://api.github.com/user‘, auth=HTTPBasicAuth(‘user‘, ‘pass‘))<Response [200]>

因为HTTP Basic Auth很常用,所以也可以直接验证:

>>> requests.get(‘https://api.github.com/user‘, auth=(‘user‘, ‘pass‘))<Response [200]>

Digest Authentication

>>> from requests.auth import HTTPDigestAuth>>> url = ‘http://httpbin.org/digest-auth/auth/user/pass‘>>> requests.get(url, auth=HTTPDigestAuth(‘user‘, ‘pass‘))<Response [200]>

OAuth 1 Authentication

>>> import requests>>> from requests_oauthlib import OAuth1>>> url = ‘https://api.twitter.com/1.1/account/verify_credentials.json‘>>> auth = OAuth1(‘YOUR_APP_KEY‘, ‘YOUR_APP_SECRET‘,                  ‘USER_OAUTH_TOKEN‘, ‘USER_OAUTH_TOKEN_SECRET‘)>>> requests.get(url, auth=auth)<Response [200]>

也可以使用自己写的验证类。比如某个web服务接受将X-Pizza报头设置成密码的验证,可以这样写验证类:

from requests.auth import AuthBaseclass PizzaAuth(AuthBase):    """Attaches HTTP Pizza Authentication to the given Request object."""    def __init__(self, username):        # setup any auth-related data here        self.username = username    def __call__(self, r):        # modify and return the request        r.headers[‘X-Pizza‘] = self.username        return r

使用:

>>> requests.get(‘http://pizzabin.org/admin‘, auth=PizzaAuth(‘kenneth‘))<Response [200]>

代理

使用代理:

import requestsproxies = {  "http": "http://10.10.1.10:3128",  "https": "http://10.10.1.10:1080",}requests.get("http://example.org", proxies=proxies)

可以设置环境变量:

$ export HTTP_PROXY="http://10.10.1.10:3128"$ export HTTPS_PROXY="http://10.10.1.10:1080"$ python>>> import requests>>> requests.get("http://example.org")

如果代理需要验证:

proxies = {    "http": "http://user:pass@10.10.1.10:3128/",}

  

 

Python Requests库:HTTP for Humans