【源码阅读】Requests

调用实例:

1 import requests
2 r = requests.get('https://www.python.org')
3 r.status_code
4 r.content
5 ....

调用实例

requests包目录:

Requests/
    —— packages/
    —— __init__.py
    —— _internal_utils.py
    —— adapters.py
    —— api.py         #api
    —— auth.py
    —— certs.py
    —— compat.py
    —— cookies.py
    —— exceotions.py
    —— hooks.py
    —— models.py      #类
    —— sessions.py
    —— status_codes.py #http状态嘛
    —— structures.py
    —— structures.py
    —— utils.py

__init__.py中引入了各大模块，requests.get相当于使用的api.get

from .api import request, get, head, post, patch, put, delete, options

get方法:

1 def get(url, params=None, **kwargs):
2 
3     kwargs.setdefault('allow_redirects', True)
4     return request('get', url, params=params, **kwargs)

get, head, post, patch, put, delete, options都指向了api.requests方法。区别在于是否初始化了'allow_redirects'的值

api.requests:

def request(method, url, **kwargs):
    """
    Usage::
      >>> import requests
      >>> req = requests.request('GET', 'http://httpbin.org/get')
      <Response [200]>
    """
    with sessions.Session() as session:
        return session.request(method=method, url=url, **kwargs)#调用了session.requests~

session.requests:

 1     def request(self, method, url,
 2         params=None,
 3         data=None,
 4         headers=None,
 5         cookies=None,
 6         files=None,
 7         auth=None,
 8         timeout=None,
 9         allow_redirects=True,
10         proxies=None,
11         hooks=None,
12         stream=None,
13         verify=None,
14         cert=None,
15         json=None):
16        
17         # Create the Request.
18         req = Request(
19             method = method.upper(),
20             url = url,
21             headers = headers,
22             files = files,
23             data = data or {},
24             json = json,
25             params = params or {},
26             auth = auth,
27             cookies = cookies,
28             hooks = hooks,
29         )# 初始化类
30         prep = self.prepare_request(req) #加工Request类，return:PreparedRequest
31 
32         proxies = proxies or {} #代理
33 
34         settings = self.merge_environment_settings(
35             prep.url, proxies, stream, verify, cert
36         )
37 
38         # Send the request.
39         send_kwargs = {
40             'timeout': timeout,
41             'allow_redirects': allow_redirects,
42         }
43         send_kwargs.update(settings)
44         resp = self.send(prep, **send_kwargs) #发送请求
45 
46         return resp

send:

 1  def send(self, request, **kwargs):
 2 
 3         kwargs.setdefault('stream', self.stream)
 4         kwargs.setdefault('verify', self.verify)
 5         kwargs.setdefault('cert', self.cert)
 6         kwargs.setdefault('proxies', self.proxies) 7 
 8         if isinstance(request, Request):
 9             raise ValueError('You can only send PreparedRequests.')
10 
11         allow_redirects = kwargs.pop('allow_redirects', True)
12         stream = kwargs.get('stream')
13         hooks = request.hooks
14 
15         if allow_redirects: 16             checked_urls = set()
17             while request.url in self.redirect_cache:
18                 checked_urls.add(request.url)
19                 new_url = self.redirect_cache.get(request.url)
20                 if new_url in checked_urls:
21                     break
22                 request.url = new_url
23 
24         adapter = self.get_adapter(url=request.url)
25 
26         start = datetime.utcnow()
27 
28         r = adapter.send(request, **kwargs)
29 
30         r.elapsed = datetime.utcnow() - start
31 
32         r = dispatch_hook('response', hooks, r, **kwargs)
33 
34         if r.history:
35 
36             for resp in r.history:
37                 extract_cookies_to_jar(self.cookies, resp.request, resp.raw)
38 
39         extract_cookies_to_jar(self.cookies, request, r.raw)
40 
41         gen = self.resolve_redirects(r, request, **kwargs)
42 
43         history = [resp for resp in gen] if allow_redirects else []
44 
45         if history:
46             history.insert(0, r)
47             r = history.pop()
48             r.history = history
49 
50         if not stream:
51             r.content
52 
53         return r