C#首次登录请求后，在后面的所有请求接口中需要带上Cookie，写一个详细完整的HttpHelper请求帮助类

在C#中创建一个带Cookie重用功能的HTTP请求辅助类（假设我们叫它`CookieBasedHttpHelper`），可以按照以下步骤设计：

1. 引入必要的命名空间：

using System;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;

2. 定义一个基础请求类，继承自HttpClient并维护一个 cookie jar：

public class CookieBasedHttpClient : HttpClient
{
    private readonly CookieContainer _cookieContainer;

    public CookieBasedHttpClient()
    {
        _cookieContainer = new CookieContainer();
    }

    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        // 先尝试从容器中获取现有Cookie
        var cookiesFromJar = await GetCookiesFromContainer(request.RequestUri);

        // 如果有Cookie，则添加到请求头
        if (cookiesFromJar.Count > 0)
            request.Headers.Add(HttpRequestHeader.Cookie, string.Join("; ", cookiesFromJar));

        // 发送原始请求
        var response = await base.SendAsync(request, cancellationToken);

        // 保存新Cookie
        foreach (var cookie in response.Cookies)
            _cookieContainer.Add(response.RequestMessage.RequestUri, cookie);

        return response;
    }

    private async Task<CookieCollection> GetCookiesFromContainer(Uri uri)
    {
        try
        {
            return await _cookieContainer.GetCookiesAsync(uri);
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error retrieving cookies: {ex.Message}");
            return null;
        }
    }
}

3. 创建一个封装发送请求的方法，例如`GetUrlResponse`和`GetUrlRespHtml`：

public class CookieBasedHttpHelper
{
    private readonly CookieBasedHttpClient _client;

    public CookieBasedHttpHelper()
    {
        _client = new CookieBasedHttpClient();
    }

    public async Task<HttpResponseMessage> getUrlResponse(string url)
    {
        return await _client.GetAsync(url);
    }

    public async Task<string> getUrlRespHtml(string url)
    {
        var response = await getUrlResponse(url);
        using (var content = await response.Content.ReadAsStreamAsync())
        {
            return Encoding.UTF8.GetString(content.ToArray());
        }
    }

    // 设置代理IP的方法（如果需要）
    public void SetProxy(string proxyAddress, int port)
    {
        _client.BaseAddress = new Uri(proxyAddress);
    }
}

现在你可以使用`CookieBasedHttpHelper`类来发起请求，每次请求都会自动携带上之前的Cookie。示例用法如下：

CookieBasedHttpHelper helper = new CookieBasedHttpHelper();

// 第一次登录请求，保存登录产生的Cookie
HttpResponseMessage loginResponse = await helper.getUrlResponse(loginEndpoint);

// 后续接口请求
string homepageContent = await helper.getUrlRespHtml(homepageEndpoint);