Python接口自动化之request请求封装

我们在做自动化测试的时候，大家都是希望自己写的代码越简洁越好，代码重复量越少越好。那么，我们可以考虑将request的请求类型（如：Get、Post、Delect请求）都封装起来。这样，我们在编写用例的时候就可以直接进行请求了。

1. 源码分析

我们先来看一下Get、Post、Delect等请求的源码，看一下它们都有什么特点。

（1）Get请求源码

 def get(self, url, **kwargs):
  r"""Sends a GET request. Returns :class:`Response` object.
  :param url: URL for the new :class:`Request` object.
     :param \*\*kwargs: Optional arguments that ``request`` takes.
     :rtype: requests.Response
      """
  
  kwargs.setdefault('allow_redirects', True)
  return self.request('GET', url, **kwargs)

（2）Post请求源码

def post(self, url, data=None, json=None, **kwargs):
  r"""Sends a POST request. Returns :class:`Response` object.
  :param url: URL for the new :class:`Request` object.
     :param data: (optional) Dictionary, list of tuples, bytes, or file-like
  object to send in the body of the :class:`Request`.
  :param json: (optional) json to send in the body of the :class:`Request`.
  :param \*\*kwargs: Optional arguments that ``request`` takes.
  :rtype: requests.Response
  """
 
  return self.request('POST', url, data=data, json=json, **kwargs)

（3）Delect请求源码

 def delete(self, url, **kwargs):
        r"""Sends a DELETE request. Returns :class:`Response` object.
        :param url: URL for the new :class:`Request` object.
        :param \*\*kwargs: Optional arguments that ``request`` takes.
        :rtype: requests.Response
        """
    
        return self.request('DELETE', url, **kwargs)

（4）分析结果

我们发现，不管是Get请求、还是Post请求或者是Delect请求，它们到最后返回的都是request函数。那么，我们再去看一看request函数的源码。

 def request(self, method, url,
         params=None, data=None, headers=None, cookies=None, files=None,
         auth=None, timeout=None, allow_redirects=True, proxies=None,
         hooks=None, stream=None, verify=None, cert=None, json=None):
     """Constructs a :class:`Request <Request>`, prepares it and sends it.
     Returns :class:`Response <Response>` object.
 
     :param method: method for the new :class:`Request` object.
     :param url: URL for the new :class:`Request` object.
     :param params: (optional) Dictionary or bytes to be sent in the query
         string for the :class:`Request`.
     :param data: (optional) Dictionary, list of tuples, bytes, or file-like
         object to send in the body of the :class:`Request`.
     :param json: (optional) json to send in the body of the
         :class:`Request`.
     :param headers: (optional) Dictionary of HTTP Headers to send with the
         :class:`Request`.
     :param cookies: (optional) Dict or CookieJar object to send with the
         :class:`Request`.
     :param files: (optional) Dictionary of ``'filename': file-like-objects``
         for multipart encoding upload.
     :param auth: (optional) Auth tuple or callable to enable
         Basic/Digest/Custom HTTP Auth.
     :param timeout: (optional) How long to wait for the server to send
         data before giving up, as a float, or a :ref:`(connect timeout,
         read timeout) <timeouts>` tuple.
     :type timeout: float or tuple
     :param allow_redirects: (optional) Set to True by default.
     :type allow_redirects: bool
     :param proxies: (optional) Dictionary mapping protocol or protocol and
         hostname to the URL of the proxy.
     :param stream: (optional) whether to immediately download the response
         content. Defaults to ``False``.
     :param verify: (optional) Either a boolean, in which case it controls whether we verify
         the server's TLS certificate, or a string, in which case it must be a path
         to a CA bundle to use. Defaults to ``True``.
     :param cert: (optional) if String, path to ssl client cert file (.pem).
         If Tuple, ('cert', 'key') pair.
     :rtype: requests.Response
     """
     # Create the Request.
     req = Request(
         method=method.upper(),
         url=url,
         headers=headers,
         files=files,
         data=data or {},
         json=json,
         params=params or {},
         auth=auth,
         cookies=cookies,
         hooks=hooks,
     )
     prep = self.prepare_request(req)
 
     proxies = proxies or {}
 
     settings = self.merge_environment_settings(
         prep.url, proxies, stream, verify, cert
     )
 
     # Send the request.
     send_kwargs = {
         'timeout': timeout,
         'allow_redirects': allow_redirects,
     }
     send_kwargs.update(settings)
     resp = self.send(prep, **send_kwargs)
 
     return resp

从request源码可以看出，它先创建一个Request，然后将传过来的所有参数放在里面，再接着调用self.send()，并将Request传过去。这里我们将不在分析后面的send等方法的源码了，有兴趣的同学可以自行了解。

分析完源码之后发现，我们可以不需要单独在一个类中去定义Get、Post等其他方法，然后在单独调用request。其实，我们直接调用request即可。

2. requests请求封装

代码示例：

 import requests
 
 class RequestMain:
     def __init__(self):
         """
 
         session管理器
         requests.session(): 维持会话,跨请求的时候保存参数
         """
         # 实例化session
         self.session = requests.session()
 
     def request_main(self, method, url, params=None, data=None, json=None, headers=None, **kwargs):
         """
 
         :param method: 请求方式
         :param url: 请求地址
         :param params: 字典或bytes，作为参数增加到url中         
   :param data: data类型传参，字典、字节序列或文件对象，作为Request的内容
         :param json: json传参，作为Request的内容
         :param headers: 请求头，字典
         :param kwargs: 若还有其他的参数，使用可变参数字典形式进行传递
         :return:
         """
 
         # 对异常进行捕获
         try:
             """
             
             封装request请求，将请求方法、请求地址，请求参数、请求头等信息入参。
             注 ：verify: True/False，默认为True，认证SSL证书开关；cert: 本地SSL证书。如果不需要ssl认证，可将这两个入参去掉
             """
             re_data = self.session.request(method, url, params=params, data=data, json=json, headers=headers, cert=(client_crt, client_key), verify=False, **kwargs)
         # 异常处理 报错显示具体信息
         except Exception as e:
             # 打印异常
             print("请求失败：{0}".format(e))
         # 返回响应结果
         return re_data


 if __name__ == '__main__':
     # 请求地址
     url = '请求地址'
     # 请求参数
     payload = {"请求参数"}
     # 请求头
     header = {"headers"}
     # 实例化 RequestMain()
     re = RequestMain()
     # 调用request_main，并将参数传过去
     request_data = re.request_main("请求方式", url, json=payload, headers=header)
     # 打印响应结果
     print(request_data.text)

注：如果你调的接口不需要SSL认证，可将cert与verify两个参数去掉。

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