写一个webservice万能客户端

一个万能客户端通常需要以下功能：

1. 支持HTTP和HTTPS协议；
2. 支持GET、POST、PUT、DELETE等HTTP请求方法；
3. 支持HTTP Basic认证；
4. 支持请求头和请求体的设置；
5. 支持请求参数的设置；
6. 支持响应状态码、响应头和响应体的获取；
7. 支持文件上传和下载；
8. 支持SSL证书验证；
9. 支持代理设置。

下面是一个基于Python的简单实现，使用requests库：

import requests

class UniversalClient:
    def __init__(self):
        self.session = requests.Session()
    
    def _prepare_request(self, method, url, headers=None, params=None, data=None, files=None, auth=None, timeout=None, verify=True, proxies=None):
        req = requests.Request(method, url, headers=headers, params=params, data=data, files=files, auth=auth)
        return self.session.prepare_request(req)
    
    def request(self, method, url, headers=None, params=None, data=None, files=None, auth=None, timeout=None, verify=True, proxies=None):
        req = self._prepare_request(method, url, headers=headers, params=params, data=data, files=files, auth=auth, timeout=timeout, verify=verify, proxies=proxies)
        resp = self.session.send(req, timeout=timeout, verify=verify, proxies=proxies)
        return resp
    
    def get(self, url, headers=None, params=None, auth=None, timeout=None, verify=True, proxies=None):
        return self.request('GET', url, headers=headers, params=params, auth=auth, timeout=timeout, verify=verify, proxies=proxies)
    
    def post(self, url, headers=None, params=None, data=None, files=None, auth=None, timeout=None, verify=True, proxies=None):
        return self.request('POST', url, headers=headers, params=params, data=data, files=files, auth=auth, timeout=timeout, verify=verify, proxies=proxies)
    
    def put(self, url, headers=None, params=None, data=None, files=None, auth=None, timeout=None, verify=True, proxies=None):
        return self.request('PUT', url, headers=headers, params=params, data=data, files=files, auth=auth, timeout=timeout, verify=verify, proxies=proxies)
    
    def delete(self, url, headers=None, params=None, data=None, files=None, auth=None, timeout=None, verify=True, proxies=None):
        return self.request('DELETE', url, headers=headers, params=params, data=data, files=files, auth=auth, timeout=timeout, verify=verify, proxies=proxies)

使用示例：

client = UniversalClient()

# 发送GET请求
resp = client.get('http://example.com')

# 发送POST请求，带JSON请求体和请求头
headers = {'Content-Type': 'application/json'}
data = {'name': 'John', 'age': 25}
resp = client.post('http://example.com', headers=headers, data=data)

# 发送带文件的POST请求
files = {'file': open('example.txt', 'rb')}
resp = client.post('http://example.com/upload', files=files)

# 发送带HTTP Basic认证的请求
auth = ('username', 'password')
resp = client.get('http://example.com', auth=auth)