Python接口自动化之request请求封装

作者：Gakki

1. 背景

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。

2. 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。

3. 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。

4. 总结

本文只是简单的介绍了Python接口自动化之request请求封装，后期还有许多优化的地方，希望和大家一起来探讨。