HttpClientStudy/Docs/1.4.2.高级使用.使用管道.ipynb

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   "source": [
    "# HttpClient 管道黑科技，让你的请求效率飞起来！🚀"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Pipeline(管道)是HttpClient网络请求的`隐形加速器`。\n",
    "\n",
    "HttpClient 采用了与 ASP.NET Core 管道机制相同的设计，通过组合 `HttpMessageHandler` 和 `中间件模式` 形成请求/响应链来实现。允许你在请求和响应之间插入多个处理步骤，这些步骤可以按顺序执行，类似于管道。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "- 提高性能\n",
    "    + 异步流水线式处理：利用async/await串联管道，实现非阻塞的请求-响应流水线，提升吞吐量；\n",
    "    + 资源高效使用：结合IHttpClientFactory自动管理连接池，高效使用HttpClient实例；\n",
    "\n",
    "- 优化程序设计\n",
    "    + 职责分离：将请求处理拆分为多个独立管道（如认证、日志、重试），每个管道专注单一功能；\n",
    "    + 可插拔性‌：通过增减管道，动态调整处理流程（如临时添加请求加密步骤），无需修改核心逻辑；\n",
    "    + 统一扩展点：为整个请求流程，形成统一的扩展点；结合AOP模式，更容易实现统一日志、权限、拦截、自定义流程等扩展功能。\n",
    "\n",
    "- 增加可维护\n",
    "    + 基于管道，形成模块化、可扩展化程序设计，提高可维护性；\n",
    "    + 调试友好：每个管道可单独测试、跟踪；"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 初始化"
   ]
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     "data": {
      "text/markdown": [
       "## 初始化\n",
       "这是全局共用文件，包括Nuget包引用、全局类库引用、全局文件引用、全局命名空间引用、全局变量、全局方法、全局类定义等功能。\n",
       "\n",
       "在业务笔记中引用，执行其它单元格之前先执行一次。"
      ]
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       "<div><div></div><div></div><div><strong>Installed Packages</strong><ul><li><span>Microsoft.Extensions.DependencyInjection, 9.0.5</span></li><li><span>Microsoft.Extensions.Http, 9.0.5</span></li><li><span>Microsoft.Extensions.Http.Polly, 9.0.5</span></li><li><span>Microsoft.Extensions.Logging, 9.0.5</span></li><li><span>Microsoft.Extensions.Logging.Console, 9.0.5</span></li><li><span>Microsoft.Net.Http.Headers, 9.0.5</span></li><li><span>Polly, 8.5.2</span></li><li><span>Refit, 8.0.0</span></li><li><span>Refit.HttpClientFactory, 8.0.0</span></li><li><span>System.Net.Http.Json, 9.0.5</span></li></ul></div></div>"
      ]
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     "text": [
      "配置文件根目录：c:\\Users\\ruyu\\Desktop\\HttpClientStudy\\Docs\\Publish\\HttpClientStudy.Core\n",
      "配置文件根目录：c:\\Users\\ruyu\\Desktop\\HttpClientStudy\\Docs\\Publish\\HttpClientStudy.Core\n",
      "启动WebApi项目...\n",
      "程序[c:\\Users\\ruyu\\Desktop\\HttpClientStudy\\Docs\\Publish\\HttpClientStudy.WebApp\\HttpClientStudy.WebApp.exe]已在新的命令行窗口执行。如果未出现新命令行窗口，可能是程序错误造成窗口闪现！\n",
      "已启动WebApi项目,保持窗口打开状态！\n",
      "初始化完成！\n"
     ]
    }
   ],
   "source": [
    "#!import \"./Ini.ipynb\""
   ]
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   "source": [
    "## 1、创建自定义 HttpMessageHandler"
   ]
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   "source": [
    "/// <summary>\n",
    "/// 日志管道(中间件)\n",
    "/// </summary>\n",
    "public class LoggingHandler : DelegatingHandler\n",
    "{\n",
    "    public LoggingHandler()\n",
    "    {\n",
    "        //防止成为最后一个管道时异常\n",
    "        this.InnerHandler = new SocketsHttpHandler();\n",
    "    }\n",
    "    \n",
    "    protected override HttpResponseMessage Send(HttpRequestMessage request, CancellationToken cancellationToken)\n",
    "    {\n",
    "        Console.WriteLine(\"日志管道: LoggingHandler -> Send -> Before\");\n",
    "\n",
    "        HttpResponseMessage response = base.Send(request, cancellationToken);\n",
    "        response.EnsureSuccessStatusCode();\n",
    "\n",
    "        Console.WriteLine(\"日志管道: LoggingHandler -> Send -> After\");\n",
    "\n",
    "        return response;\n",
    "    }\n",
    "\n",
    "    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)\n",
    "    {\n",
    "        // 记录请求信息\n",
    "        Console.WriteLine($\"日志管道: LoggingHandler -> Send -> Before Request: {request.Method} {request.RequestUri}\");\n",
    "        // 调用管道中的下一个处理器，并获取响应\n",
    "        var response = await base.SendAsync(request, cancellationToken);\n",
    "        // 记录响应信息\n",
    "        Console.WriteLine($\"日志管道: LoggingHandler -> Send -> After Response: {response.StatusCode}\");\n",
    "        return response;\n",
    "    }\n",
    "}\n",
    "\n",
    "/// <summary>\n",
    "/// 令牌验证管道(中间件)\n",
    "/// </summary>\n",
    "public class TokenDelegatingHandler : DelegatingHandler \n",
    "{\n",
    "    public TokenDelegatingHandler()\n",
    "    {\n",
    "        //防止成为最后一个管道时异常\n",
    "        this.InnerHandler = new SocketsHttpHandler();\n",
    "    }\n",
    "\n",
    "    protected override HttpResponseMessage Send(HttpRequestMessage request, CancellationToken cancellationToken)\n",
    "    {\n",
    "        Console.WriteLine(\"令牌验证管道: TokenDelegatingHandler -> Send -> Added Token\");\n",
    "\n",
    "        if (!request.Headers.Contains(Microsoft.Net.Http.Headers.HeaderNames.Authorization)) \n",
    "        {\n",
    "            Console.WriteLine(\"没有 Token, TokenDelegatingHandler 添加之\");\n",
    "            request.Headers.Add(Microsoft.Net.Http.Headers.HeaderNames.Authorization, \"Bearer \" + \"a.b.c\");\n",
    "        }\n",
    "        else\n",
    "        {\n",
    "            Console.WriteLine($\"已有Token, {request.Headers.Authorization}\");\n",
    "        }\n",
    "\n",
    "        HttpResponseMessage response = base.Send(request, cancellationToken);\n",
    "\n",
    "        Console.WriteLine(\"令牌验证管道: TokenDelegatingHandler -> Send -> After\");\n",
    "\n",
    "        return response;\n",
    "    }\n",
    "\n",
    "    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)\n",
    "    {\n",
    "        Console.WriteLine(\"令牌验证管道: TokenDelegatingHandler -> SendAsync -> Before\");\n",
    "\n",
    "        HttpResponseMessage response = await base.SendAsync(request, cancellationToken);\n",
    "\n",
    "        Console.WriteLine(\"令牌验证管道: TokenDelegatingHandler -> SendAsync -> After\");\n",
    "\n",
    "        return response;\n",
    "    }\n",
    "}\n",
    "\n",
    "///<summary>\n",
    "/// 异常处理管道(中间件)\n",
    "/// </summary>\n",
    "public class ExceptionDelegatingHandler : DelegatingHandler\n",
    "{\n",
    "    public ExceptionDelegatingHandler()\n",
    "    {\n",
    "        //防止成为最后一个管道时异常\n",
    "        this.InnerHandler = new SocketsHttpHandler();\n",
    "    }\n",
    "\n",
    "    protected override HttpResponseMessage Send(HttpRequestMessage request, CancellationToken cancellationToken)\n",
    "    {\n",
    "        Console.WriteLine(\"异常处理管道: ExceptionDelegatingHandler -> Send -> Before\");\n",
    "\n",
    "        HttpResponseMessage response;\n",
    "        try \n",
    "        {\n",
    "            response = base.Send(request, cancellationToken);\n",
    "            response.EnsureSuccessStatusCode();\n",
    "        }\n",
    "        catch(Exception ex)\n",
    "        {\n",
    "            Console.WriteLine($\"异常管道中间件，监控到异常：{ex.Message}\");\n",
    "\n",
    "            response = new HttpResponseMessage(HttpStatusCode.ExpectationFailed);\n",
    "        }\n",
    "        finally\n",
    "        {\n",
    "            //清理业务\n",
    "        }\n",
    "        \n",
    "        Console.WriteLine(\"异常处理管道: ExceptionDelegatingHandler -> Send -> After\");\n",
    "\n",
    "        return response;\n",
    "    }\n",
    "\n",
    "    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)\n",
    "    {\n",
    "        Console.WriteLine(\"异常处理管道: ExceptionDelegatingHandler -> SendAsync -> Before\");\n",
    "\n",
    "        HttpResponseMessage response;\n",
    "        try \n",
    "        {\n",
    "            response = response = await base.SendAsync(request, cancellationToken);\n",
    "            response.EnsureSuccessStatusCode();\n",
    "        }\n",
    "        catch(Exception ex)\n",
    "        {\n",
    "            Console.WriteLine($\"异常管道中间件，监控到异常：{ex.Message}\");\n",
    "\n",
    "            response = new HttpResponseMessage(HttpStatusCode.ExpectationFailed);\n",
    "        }\n",
    "        finally\n",
    "        {\n",
    "            //清理业务\n",
    "        }\n",
    "\n",
    "        Console.WriteLine(\"异常处理管道: ExceptionDelegatingHandler -> SendAsync -> After\");\n",
    "\n",
    "        return response;\n",
    "    }\n",
    "}"
   ]
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   "metadata": {},
   "source": [
    "## 2、组合多个 HttpMessageHandler 形成请求/响应管道(处理链)"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "组合管道，就是利用 DelegatingHandler 类的 InnerHandler 属性,指定本管道的下一个管道(中间件)，将多个管道链接起来，形成一个`请求/响应`处理链。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "+ 默认管道"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
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     "name": "stdout",
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     "text": [
      "响应内容：Pong\r\n"
     ]
    }
   ],
   "source": [
    "{   //默认配置\n",
    "    var httpClient = new HttpClient()\n",
    "    {\n",
    "        BaseAddress = webApiBaseUri\n",
    "    };\n",
    "\n",
    "    //发送请求，从日志看管道执行顺序\n",
    "    var response = await httpClient.GetAsync(\"/api/Hello/Ping\");\n",
    "\n",
    "    var content = await response.Content.ReadAsStringAsync();\n",
    "\n",
    "    Console.WriteLine($\"响应内容：{content}\");\n",
    "}"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "+ 手动组合"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
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   "outputs": [
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     "output_type": "stream",
     "text": [
      "令牌验证管道: TokenDelegatingHandler -> SendAsync -> Before\n",
      "异常处理管道: ExceptionDelegatingHandler -> SendAsync -> Before\n",
      "日志管道: LoggingHandler -> Send -> Before Request: GET http://127.0.0.1:5189/api/Config/GetApiConfig\n",
      "日志管道: LoggingHandler -> Send -> After Response: OK\n",
      "异常处理管道: ExceptionDelegatingHandler -> SendAsync -> After\n",
      "令牌验证管道: TokenDelegatingHandler -> SendAsync -> After\n",
      "响应内容：{\"data\":{\"host\":\"localhost\",\"port\":5189,\"scheme\":\"http\",\"pathBase\":\"\",\"baseUrl\":\"http://localhost:5189\",\"webAppMutexName\":\"HttpClientStudy.WebApp\"},\"code\":1,\"message\":\"成功\"}\n"
     ]
    }
   ],
   "source": [
    "{   //组装管道\n",
    "\n",
    "    /*\n",
    "        1. 最后一个管道必须是SocketsHttpHandler 或者 保证最后的管道的InnerHandler有默认值\n",
    "        2. 倒序组装，正序执行：HttpClient构造函数，传入的HttpMessageHandler是第一个执行的，其InnerHandler是下一个执行的，依次类推\n",
    "    */\n",
    "\n",
    "    var lastHandler = new SocketsHttpHandler()\n",
    "    {\n",
    "        UseCookies =  false,\n",
    "        UseProxy = false,\n",
    "    };\n",
    "\n",
    "    var logPipeline = new LoggingHandler()\n",
    "    {\n",
    "        InnerHandler  = lastHandler\n",
    "    };\n",
    "    \n",
    "    var exceptionHandler = new ExceptionDelegatingHandler()\n",
    "    {\n",
    "        InnerHandler = logPipeline\n",
    "    };\n",
    "\n",
    "    var tokenHandler = new TokenDelegatingHandler()\n",
    "    {\n",
    "        InnerHandler = exceptionHandler\n",
    "    };\n",
    "\n",
    "    var httpClient = new HttpClient(tokenHandler)\n",
    "    {\n",
    "        BaseAddress = webApiBaseUri\n",
    "    };\n",
    "\n",
    "    //发送请求，从日志看管道执行顺序\n",
    "    var response = await httpClient.GetAsync(\"/api/Config/GetApiConfig\");\n",
    "\n",
    "    var content = await response.Content.ReadAsStringAsync();\n",
    "\n",
    "    Console.WriteLine($\"响应内容：{content}\");\n",
    "}"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "+ 动态组合"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "整个管道链的组装，是非常灵活的，动态组装也不是难事！"
   ]
  },
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     "data": {
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       "http://127.0.0.1:5189"
      ]
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     "text": [
      "令牌验证管道: TokenDelegatingHandler -> SendAsync -> Before\n",
      "日志管道: LoggingHandler -> Send -> Before Request: GET http://127.0.0.1:5189/api/Config/GetApiConfig\n",
      "异常处理管道: ExceptionDelegatingHandler -> SendAsync -> Before\n",
      "异常处理管道: ExceptionDelegatingHandler -> SendAsync -> After\n",
      "日志管道: LoggingHandler -> Send -> After Response: OK\n",
      "令牌验证管道: TokenDelegatingHandler -> SendAsync -> After\n",
      "响应内容：{\"data\":{\"host\":\"localhost\",\"port\":5189,\"scheme\":\"http\",\"pathBase\":\"\",\"baseUrl\":\"http://localhost:5189\",\"webAppMutexName\":\"HttpClientStudy.WebApp\"},\"code\":1,\"message\":\"成功\"}\n"
     ]
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   ],
   "source": [
    "/// <summary>\n",
    "/// 管道构建器\n",
    "/// </summary>\n",
    "public class HttpMessageHandlerBuilder\n",
    "{\n",
    "    public List<DelegatingHandler> Handlers { get; set; }\n",
    "\n",
    "    public HttpMessageHandlerBuilder()\n",
    "    {\n",
    "        this.Handlers = new List<DelegatingHandler>();\n",
    "    }\n",
    "\n",
    "    public HttpMessageHandlerBuilder(List<DelegatingHandler> handlers):base()\n",
    "    {\n",
    "        if(handlers != null)\n",
    "        {\n",
    "            this.Handlers = handlers;\n",
    "        }\n",
    "    }\n",
    "\n",
    "    public void AddHttpMessageHandler(DelegatingHandler handler)\n",
    "    {\n",
    "        Handlers.Add(handler);\n",
    "    }\n",
    "\n",
    "    public void RemoveHttpMessageHandler(DelegatingHandler handler)\n",
    "    {\n",
    "        Handlers.Remove(handler);\n",
    "    }\n",
    "\n",
    "    public List<DelegatingHandler> FindHttpMessageHandler(DelegatingHandler handler)\n",
    "    {\n",
    "        return Handlers.Where(h => h.GetType() == handler.GetType()).ToList();\n",
    "    }\n",
    "\n",
    "    ///  <summary>\n",
    "    ///  根据管道配置：创建一个新HttpClient实例\n",
    "    ///  </summary>\n",
    "    public HttpClient Build()\n",
    "    {\n",
    "        if(this.Handlers ==null ||  this.Handlers.Count == 0)\n",
    "        {\n",
    "            return new HttpClient();\n",
    "        }\n",
    "\n",
    "        //默认最终处理器\n",
    "        HttpMessageHandler defaultLastHandler = new SocketsHttpHandler()\n",
    "        {\n",
    "            //自定义配置\n",
    "            PooledConnectionLifetime = TimeSpan.FromSeconds(120),\n",
    "        };\n",
    "\n",
    "        //倒序组装：完成后执行顺序与注册顺序一致\n",
    "        //拷贝份，省得多次调用有问题\n",
    "\n",
    "        HttpMessageHandler currentHandler = new SocketsHttpHandler()\n",
    "        {\n",
    "            //自定义配置\n",
    "            PooledConnectionLifetime = TimeSpan.FromSeconds(120),\n",
    "        };\n",
    "\n",
    "        var builderHandlers = this.Handlers.ToList<DelegatingHandler>();\n",
    "        builderHandlers.Reverse();\n",
    "\n",
    "        if(builderHandlers[0].InnerHandler != null)\n",
    "        {\n",
    "            currentHandler = builderHandlers[0].InnerHandler;\n",
    "        }\n",
    "\n",
    "        for (int i = 0; i < builderHandlers.Count; i++)\n",
    "        {\n",
    "            builderHandlers[i].InnerHandler = currentHandler;\n",
    "            currentHandler = builderHandlers[i];\n",
    "        }\n",
    "\n",
    "        // 利用管道创建HttpClient\n",
    "        var httpClient = new HttpClient(currentHandler);\n",
    "\n",
    "        return httpClient;\n",
    "    }\n",
    "}\n",
    "\n",
    "//构建管道\n",
    "List<DelegatingHandler> handlers = new List<DelegatingHandler>()\n",
    "{\n",
    "    new TokenDelegatingHandler(),\n",
    "};\n",
    "\n",
    "//添加\n",
    "handlers.Add(new LoggingHandler());\n",
    "handlers.Add(new ExceptionDelegatingHandler());\n",
    "\n",
    "var handlerBuilder = new HttpMessageHandlerBuilder(handlers);\n",
    "\n",
    "//第一次：发送请求，从日志看管道执行顺序\n",
    "var httpClient = handlerBuilder.Build();\n",
    "httpClient.BaseAddress = webApiBaseUri;\n",
    "webApiBaseUrl.Display();\n",
    "var response = await httpClient.GetAsync(\"/api/Config/GetApiConfig\");\n",
    "var content = await response.Content.ReadAsStringAsync();\n",
    "\n",
    "Console.WriteLine($\"响应内容：{content}\");\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 3、发送请求"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "和一般的请求，没什么区别。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 4、管道执行顺序"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "+ 请求从最外层的 DelegatingHandler 开始，逐层进入内部处理器。\n",
    "+ 响应则从最内层返回，经过每一层的 SendAsync 方法后返回给调用者。\n",
    "\n",
    "执行下面示例，查看日志输出："
   ]
  },
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     "output_type": "stream",
     "text": [
      "令牌验证管道: TokenDelegatingHandler -> SendAsync -> Before\n",
      "异常处理管道: ExceptionDelegatingHandler -> SendAsync -> Before\n",
      "日志管道: LoggingHandler -> Send -> Before Request: GET http://127.0.0.1:5189/api/Hello/Ping\n",
      "日志管道: LoggingHandler -> Send -> After Response: OK\n",
      "异常处理管道: ExceptionDelegatingHandler -> SendAsync -> After\n",
      "令牌验证管道: TokenDelegatingHandler -> SendAsync -> After\n",
      "响应内容：Pong\n"
     ]
    }
   ],
   "source": [
    "{   \n",
    "    //组装管道\n",
    "    //最后一个管道，必须是SocketsHttpHandler，或者默认的是SocketsHttpHandler\n",
    "    var lastHandler = new SocketsHttpHandler()\n",
    "    {\n",
    "        UseCookies =  false,\n",
    "        UseProxy = false,\n",
    "    };\n",
    "\n",
    "    var logPipeline = new LoggingHandler()\n",
    "    {\n",
    "        InnerHandler  = lastHandler\n",
    "    };\n",
    "    \n",
    "    var exceptionHandler = new ExceptionDelegatingHandler()\n",
    "    {\n",
    "        InnerHandler = logPipeline\n",
    "    };\n",
    "\n",
    "    var tokenHandler = new TokenDelegatingHandler()\n",
    "    {\n",
    "        InnerHandler = exceptionHandler\n",
    "    };\n",
    "\n",
    "    var httpClient = new HttpClient(tokenHandler)\n",
    "    {\n",
    "        BaseAddress = webApiBaseUri\n",
    "    };\n",
    "\n",
    "    //发送请求，从日志看管道执行顺序\n",
    "    var response = await httpClient.GetAsync(\"/api/Hello/Ping\");\n",
    "\n",
    "    var content = await response.Content.ReadAsStringAsync();\n",
    "\n",
    "    Console.WriteLine($\"响应内容：{content}\");\n",
    "}"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## ５、使用 IHttpClientFactory 构建更复杂的管道（推荐）"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 小结"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "| 特性                | 描述                                                                 |\n",
    "|---------------------|----------------------------------------------------------------------|\n",
    "| HttpMessageHandler  | 是 HttpClient 的核心处理单元:ml-citation{ref=\"1\" data=\"citationList\"}                                   |\n",
    "| DelegatingHandler   | 可用于构建自定义中间件逻辑:ml-citation{ref=\"1,5\" data=\"citationList\"}                                  |\n",
    "| 管道顺序            | 请求按顺序进入，响应逆序返回:ml-citation{ref=\"5,8\" data=\"citationList\"}                                |\n",
    "| IHttpClientFactory  | 推荐用于生产环境，支持灵活配置:ml-citation{ref=\"1,7\" data=\"citationList\"}                              |\n",
    "\n",
    "通过添加更多 DelegatingHandler 实现缓存、重试、认证等！"
   ]
  }
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