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.url

u'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=payload)

>>> print(r.text)

{

  ...

  "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=json.dumps(payload))

流上传：

with open('massive-body', 'rb') as f:

    requests.post('http://some.url/streamed', data=f)

Chunk-Encoded上传：

def gen():

    yield 'hi'

    yield 'there'



requests.post('http://some.url/chunked', data=gen())

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"

}

一次性上传多个文件：

>>> url = 'http://httpbin.org/post'

>>> multiple_files = [('images', ('foo.png', open('foo.png', 'rb'), 'image/png')),

                      ('images', ('bar.png', open('bar.png', 'rb'), 'image/png'))]

>>> r = requests.post(url, files=multiple_files)

>>> r.text

{

  ...

  'files': {'images': 'data:image/png;base64,iVBORw ....'}

  'Content-Type': 'multipart/form-data; boundary=3131623adb2043caaeb5538cc7aa0b3a',

  ...

}

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=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.text

u'{"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'

如果不想一次性处理全部的数据，可以：

tarball_url = 'https://github.com/kennethreitz/requests/tarball/master'

r = requests.get(tarball_url, stream=True)

if int(r.headers['content-length']) < TOO_LONG:

  content = r.content

  ...

也可以迭代的处理数据：

with open(filename, 'wb') as fd:

    for chunk in r.iter_content(chunk_size):

        fd.write(chunk)

或者：

import json

import requests

r = requests.get('http://httpbin.org/stream/20', stream=True)

for line in r.iter_lines():

    # filter out keep-alive new lines

    if line:

        print(json.loads(line))

获取响应代码：

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

>>> r.status_code

200

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'

}

获取发送的headers

>>> r.request.headers

{'Accept-Encoding': 'identity, deflate, compress, gzip',

'Accept': '*/*', 'User-Agent': 'python-requests/1.2.0'}

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_code

200

>>> 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，Session对象在请求时允许你保留一定的参数和自动设置cookie

s = requests.Session()

s.get('http://httpbin.org/cookies/set/sessioncookie/123456789')   #cookie保留在s中

r = s.get("http://httpbin.org/cookies") #再次访问时会保留cookie

print(r.text)

# '{"cookies": {"sessioncookie": "123456789"}}'

也可以自己设置headers，cookies：

s = requests.Session()

s.auth = ('user', 'pass')

s.headers.update({'x-test': 'true'})

s.get('http://httpbin.org/headers', headers={'x-test2': 'true'})    #  'x-test' and 'x-test2' 都会被发送

预设Request

可以在发送request前做些额外的设定

from requests import Request, Session



s = Session()

req = Request('GET', url,

    data=data,

    headers=header

)

prepped = req.prepare()



# do something with prepped.body

# do something with prepped.headers



resp = s.send(prepped,

    stream=stream,

    verify=verify,

    proxies=proxies,

    cert=cert,

    timeout=timeout

)



print(resp.status_code)　

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 AuthBase

class 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]>

SSL证书验证

检查主机的ssl证书：

>>> requests.get('https://kennethreitz.com', verify=True)

    raise ConnectionError(e)

ConnectionError: HTTPSConnectionPool(host='kennethreitz.com', port=443): Max retries exceeded with url: / (Caused by <class 'socket.error'>: [Errno 10061] )

github是有的：

>>> requests.get('https://github.com', verify=True)

<Response [200]>

如果你设置验证设置为False，也可以忽略验证SSL证书。

可以读取验证文件：

>>> requests.get('https://kennethreitz.com', cert=('/path/server.crt', '/path/key'))

代理

使用代理：

import requests

proxies = {

  "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:[email protected]:3128/",

}