{ "cells": [ { "cell_type": "markdown", "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" } }, "source": [ "# HttpClient 初始化与生命周期管理" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "HttpClient 旨在实例化一次，并在应用程序的整个生命周期内重复使用。\n", "\n", "为实现复用，HttpClient类库默认使用连接池和请求管道，可以手动管理(连接池、配置管道、使用Polly); 结合IoC容器、工厂模式(提供了IHttpClientFactory类库)、复原库Polly,可以更加方便、完善的使用,这也是推荐的方法。" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## 0、初始化与全局设置" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "//全局设置，行运行一次，为后续准备\n", "#r \"nuget:System.Net.Http.Json\"\n", "#r \"nuget:Microsoft.Extensions.Http\"\n", "#r \"nuget:Microsoft.Extensions.DependencyInjection\"\n", "#r \"nuget:Microsoft.Extensions.Logging\" \n", "#r \"nuget:Microsoft.Extensions.Logging.Console\"\n", "#r \"nuget:Polly\"\n", "#r \"nuget:Microsoft.Extensions.Http.Polly\"\n", "#r \"nuget:Refit\" \n", "#r \"nuget:Refit.HttpClientFactory\"\n", "#r \"./Publish/HttpClientStudy.Core/HttpClientStudy.Core.dll\"\n", "\n", "global using System;\n", "global using System.IO;\n", "global using System.IO.Enumeration;\n", "global using System.Buffers;\n", "\n", "global using System.Collections;\n", "global using System.Collections.Concurrent;\n", "global using System.Linq;\n", "global using System.Linq.Expressions;\n", "global using System.Threading;\n", "global using System.Threading.Tasks;\n", "\n", "global using System.Net.Http;\n", "global using System.Net.Http.Json;\n", "\n", "global using Microsoft.Extensions.DependencyInjection;\n", "global using Microsoft.Extensions.DependencyInjection.Extensions;\n", "global using Microsoft.Extensions.Logging;\n", "global using Microsoft.Extensions.Logging.Console;\n", "global using Microsoft.Extensions.Http.Logging;\n", "\n", "\n", "global using Polly;\n", "global using Polly.NoOp;\n", "global using Polly.Simmy;\n", "global using Polly.Retry;\n", "global using Polly.Hedging;\n", "global using Polly.Timeout;\n", "global using Polly.Bulkhead;\n", "global using Polly.Fallback;\n", "global using Polly.RateLimit;\n", "global using Polly.CircuitBreaker;\n", "global using Polly.Utilities;\n", "global using Polly.Extensions;\n", "global using Polly.Wrap;\n", "global using Polly.Registry;\n", "global using Polly.Telemetry;\n", "\n", "global using Refit;\n", "//global using Refit.HttpClientFactory;\n", "\n", "global using HttpClientStudy.Config;\n", "global using HttpClientStudy.Core;\n", "global using HttpClientStudy.Core.Utilities;\n", "\n", "//全局变量\n", "var webApiBaseUrl = WebApiConfigManager.GetWebApiConfig().BaseUrl;\n", "var workDir = Environment.CurrentDirectory;\n", "var fullPath = System.IO.Path.GetFullPath(\"./Publish/HttpClientStudy.WebApp/HttpClientStudy.WebApp.exe\", workDir);\n", "//fullPath.Display();\n", "\n", "//启动已发布的WebApi项目\n", "Console.WriteLine(\"启动WebApi项目\");\n", "var startMessage = AppUtility.RunWebApiExeFile(fullPath);\n", "Console.WriteLine(startMessage);\n" ] }, { "cell_type": "markdown", "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "source": [ "## 1、手动管理：直接实例化-强烈不推荐" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "下面这种每次使用都实例化的用法是最常见、最`不推荐的`：\n", "\n", "因为HttpClient刚推出时不成熟及微软官方文档的示例代码是这种用法，再加上这种是最简单方便的使用方法，就造成很多人使用这种用法。\n", "这种方法有如下缺点：\n", " 1. 每次使用都实例化，造成性能开销大、容易内存泄露；\n", " 2. 并发量大、请求频繁时：网络端口会被耗尽 `Using包HttpClient,也只是在应用进程中释放了HttpClient实例，但http请求/响应是跨操作系统和网络的，而系统及网络问题在进程之上，不是进程所能处理的。`\n", " \n", "优点：\n", " 1. 使用简单，好学易用；\n", " 2. 并发量小且请求不频繁时，问题不大；" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "/*\n", " 每次请求都实例化：并发量大、请求频繁进会耗尽套接字端口\n", "*/\n", "{ \n", " var baseUrl = WebApiConfigManager.GetWebApiConfig().BaseUrl;\n", "\n", " using(var client = new HttpClient())\n", " {\n", " //发送请求\n", " var response = await client.GetAsync(baseUrl);\n", " response.EnsureSuccessStatusCode();\n", " }\n", "\n", " //显示句柄\n", " var displayValue = display($\"第 1 次请求，成功！\");\n", "\n", " for(int i=0;i<10;i++)\n", " {\n", " using(var client = new HttpClient())\n", " {\n", " var response = await client.GetAsync(baseUrl);\n", " response.EnsureSuccessStatusCode();\n", " displayValue.Update($\"第 {i+1} 次/ 共 10 次请求，成功！\");\n", " }\n", " }\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## 2、手动管理：静态类或单例" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "相比于直接new,实现了HttpClient的重用，`不推荐的`：\n", "\n", "缺点：\n", " 1. 不够灵活、优雅：特别是有多个系列的请求时；\n", " \n", "优点：\n", " 1. 复用 HttpClient\n", " 2. 实现了HttpClient的重用，减少创建和销毁的开销" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "/*\n", " 静态类/属性\n", "*/\n", "\n", "public class HttpClientHelper\n", "{\n", " public readonly static HttpClient StaticClient;\n", "\n", " static HttpClientHelper()\n", " {\n", " SocketsHttpHandler handler = new SocketsHttpHandler()\n", " {\n", " PooledConnectionLifetime = TimeSpan.FromSeconds(30),\n", " };\n", "\n", " StaticClient = new HttpClient(handler);\n", "\n", " //统一设置：请求头等\n", "\n", " //统一错误处理\n", "\n", " //当然这里也可以设置Pipline，不过这里就不演示了\n", " } \n", "\n", " public static async Task GetAsync(string url)\n", " {\n", " return await StaticClient.GetAsync(url);\n", " }\n", "\n", " public static async Task GetStringAsync(string url)\n", " {\n", " var response = await StaticClient.GetAsync(url);\n", " response.EnsureSuccessStatusCode();\n", " return await response.Content.ReadAsStringAsync();\n", " }\n", "\n", " public static async Task PostAsync(string url, HttpContent content)\n", " {\n", " return await StaticClient.PostAsync(url, content);\n", " }\n", "}\n", "\n", "{ //调用静态类\n", " var baseUrl = WebApiConfigManager.GetWebApiConfig().BaseUrl;\n", " var response = await HttpClientHelper.GetAsync(baseUrl+\"/api/Config/GetApiConfig\");\n", " var content = await response.Content.ReadAsStringAsync();\n", " Console.WriteLine(content);\n", "\n", " var response2 = await HttpClientHelper.GetStringAsync(baseUrl+\"/api/Normal/GetAllAccounts\");\n", " Console.WriteLine(response2);\n", "}" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "/*\n", " 单例实现1:\n", " 1. 私有构造函数，防止外部实例化\n", " 2. 使用静态只读变量存储类的实例，由.Net框架保证实例不变且线程安全\n", " 3. 密封类，拒绝继承，保证不被子类破坏\n", "*/\n", "\n", "// 使用Lazy实现单例\n", "public sealed class HttpClientSingleton \n", "{\n", " // 私有静态变量，用于存储类的实例\n", " private static readonly HttpClientSingleton instance = new HttpClientSingleton();\n", " \n", " //公共静态属性，用于获取类的实例\n", " public static HttpClientSingleton Instance\n", " {\n", " get\n", " {\n", " return instance;\n", " }\n", " }\n", "\n", " private readonly HttpClient Client;\n", "\n", " //私有构造函数，防止外部实例化\n", " private HttpClientSingleton() \n", " {\n", " SocketsHttpHandler handler = new SocketsHttpHandler()\n", " {\n", " PooledConnectionLifetime = TimeSpan.FromSeconds(30),\n", " };\n", "\n", " Client = new HttpClient(handler);\n", "\n", " //统一设置：请求头等\n", "\n", " //统一错误处理\n", "\n", " //可以使用IoC容器来管理\n", "\n", " //当然这里也可以设置Pipline，不过这里就不演示了\n", " Console.WriteLine(\"HttpClientSingleton 初始化一次\");\n", " }\n", "\n", " public async Task GetAsync(string url)\n", " {\n", " return await Client.GetAsync(url);\n", " }\n", "\n", " public async Task GetStringAsync(string url)\n", " {\n", " var response = await Client.GetAsync(url);\n", " response.EnsureSuccessStatusCode();\n", " return await response.Content.ReadAsStringAsync();\n", " }\n", "}\n", "\n", "{ //调用示例\n", "\n", " var baseUrl = WebApiConfigManager.GetWebApiConfig().BaseUrl;\n", " var response = await HttpClientSingleton.Instance.GetAsync(baseUrl+\"/api/Config/GetApiConfig\");\n", " var content = await response.Content.ReadAsStringAsync();\n", " Console.WriteLine(content);\n", "\n", " var response2 = await HttpClientSingleton.Instance.GetStringAsync(baseUrl+\"/api/Normal/GetAllAccounts\");\n", " Console.WriteLine(response2);\n", "}" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "/*\n", " 单例实现2:\n", " 1. 私有构造函数，防止外部实例化\n", " 2. 使用Lazy, 延迟实例化, 由.Net 框架保证线程安全\n", " 3. 密封类，拒绝继承，保证不被子类破坏\n", "*/\n", "\n", "// 由于静态初始化器是由 .NET 运行时在后台处理的，因此它是线程安全的，不需要额外的锁定机制。\n", "public sealed class HttpClientSingleton2\n", "{\n", " private static readonly Lazy _httpClientLazy = new Lazy(() =>\n", " {\n", " SocketsHttpHandler handler = new SocketsHttpHandler()\n", " {\n", " PooledConnectionLifetime = TimeSpan.FromSeconds(30)\n", " };\n", "\n", " var client = new HttpClient(handler)\n", " {\n", " // 可以在这里配置HttpClient的实例，例如设置超时时间、基地址等\n", " //Timeout = TimeSpan.FromSeconds(30),\n", " //BaseAddress = new Uri(\"https://api.example.com/\"),\n", " };\n", "\n", "\n", " //统一设置：请求头等\n", "\n", " //统一错误处理\n", "\n", " //可以使用IoC容器来管理\n", "\n", " //当然这里也可以设置Pipline，不过这里就不演示了\n", " Console.WriteLine(\"HttpClientSingleton2 初始化一次\");\n", "\n", " return client;\n", " });\n", "\n", " public static HttpClient Instance => _httpClientLazy.Value;\n", "\n", " // 私有构造函数，防止外部实例化\n", " private HttpClientSingleton2() { } \n", "\n", " public async Task GetAsync(string url)\n", " {\n", " return await _httpClientLazy.Value.GetAsync(url);\n", " }\n", "\n", " public async Task GetStringAsync(string url)\n", " {\n", " var response = await _httpClientLazy.Value.GetAsync(url);\n", " response.EnsureSuccessStatusCode();\n", " return await response.Content.ReadAsStringAsync();\n", " }\n", "}\n", "\n", "{ //调用示例\n", "\n", " var baseUrl = WebApiConfigManager.GetWebApiConfig().BaseUrl;\n", " var response = await HttpClientSingleton2.Instance.GetAsync(baseUrl+\"/api/Config/GetApiConfig\");\n", " var content = await response.Content.ReadAsStringAsync();\n", " Console.WriteLine(content);\n", "\n", " var response2 = await HttpClientSingleton2.Instance.GetStringAsync(baseUrl+\"/api/Normal/GetAllAccounts\");\n", " Console.WriteLine(response2);\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## 3、手动管理：多工具类(每类请求对应一种工具类或单例类)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "把不同类别的请求分成不同的工具类，业务类直接封装成工具类的方法。类似类型化的客户端。 简单使用的话，`比较推荐`\n", "\n", "优点:\n", " 1. 复用HttpClient\n", " 2. 可以灵活的进行统一配置\n", " 3. 不同类别不同工具类，方便定制\n", " 4. 业务直接封装成工具类方法，调用方便、快捷\n", "\n", "缺点：\n", " 1. 工具类比较多，需要手动维护\n", " 2. 工具类方法比较多且和业务直接相关，需要手动维护\n" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "// 百度服务类\n", "public sealed class BaiduService \n", "{\n", " private readonly HttpClient _httpClient;\n", " public BaiduService()\n", " {\n", " //初始化httpClient\n", " var baseHander = new SocketsHttpHandler() \n", " { \n", " MaxConnectionsPerServer = 1000 \n", " };\n", "\n", " _httpClient = new HttpClient(baseHander)\n", " {\n", " Timeout = TimeSpan.FromSeconds(10),\n", " BaseAddress = new Uri(\"http://www.baidu.com\"),\n", " };\n", " }\n", "\n", " ///// \n", " /// 获取百度首页长度\n", " /// \n", " public async Task GetIndexLengthAsync(string url)\n", " {\n", " var response = await _httpClient.GetAsync(url);\n", " response.EnsureSuccessStatusCode();\n", " var result = await response.Content.ReadAsStringAsync();\n", " return result.Length;\n", " }\n", "}\n", "//调用示例\n", "{\n", " var service = new BaiduService();\n", " var result = await service.GetIndexLengthAsync(\"/\");\n", " Console.WriteLine(result);\n", "}" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "// 本机服务类\n", "// 百度服务类\n", "public sealed class LocalService \n", "{\n", " private readonly HttpClient _httpClient;\n", " public LocalService()\n", " {\n", " //初始化httpClient\n", " var baseHander = new SocketsHttpHandler() \n", " { \n", " MaxConnectionsPerServer = 1000 \n", " };\n", "\n", " _httpClient = new HttpClient(baseHander)\n", " {\n", " Timeout = TimeSpan.FromSeconds(10),\n", " BaseAddress = new Uri(WebApiConfigManager.GetWebApiConfig().BaseUrl),\n", " };\n", " }\n", "\n", " ///// \n", " /// 获取百度首页长度\n", " /// \n", " public async Task GetIndexAsync(string url)\n", " {\n", " var response = await _httpClient.GetAsync(url);\n", " response.EnsureSuccessStatusCode();\n", " var result = await response.Content.ReadAsStringAsync();\n", " return result;\n", " }\n", "}\n", "//调用示例\n", "{\n", " var service2 = new LocalService();\n", " var result = await service2.GetIndexAsync(\"/api/Simple/GetAccount\");\n", " Console.WriteLine(result);\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## 4、手动管理：可复原(Polly)请求" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "#r \"nuget:Polly\"\n", "#r \"nuget:Microsoft.Extensions.Http.Polly\"\n", "\n", "using Polly;\n", "using Polly.Simmy;\n", "using Polly.Retry;\n", "using Polly.Extensions;\n", "{\n", " var pipleLine = new ResiliencePipelineBuilder()\n", " .AddRetry(new RetryStrategyOptions()\n", " {\n", " ShouldHandle = new PredicateBuilder().Handle(),\n", " MaxRetryAttempts = 3, // Retry up to 3 times\n", " OnRetry = args =>\n", " {\n", " // Due to how we have defined ShouldHandle, this delegate is called only if an exception occurred.\n", " // Note the ! sign (null-forgiving operator) at the end of the command.\n", " var exception = args.Outcome.Exception!; // The Exception property is nullable\n", " Console.WriteLine(\"内部重试\");\n", " return default;\n", " }\n", " })\n", " .Build();\n", "\n", " var BaseUrl = WebApiConfigManager.GetWebApiConfig().BaseUrl;\n", " HttpClient client = new HttpClient(new SocketsHttpHandler(){})\n", " {\n", " BaseAddress = new Uri(BaseUrl),\n", " };\n", "\n", " try\n", " {\n", " await pipleLine.ExecuteAsync(async (inneerToken)=>\n", " {\n", " var response = await client.GetAsync(\"api/Polly8/RetryException\",inneerToken);\n", " response.EnsureSuccessStatusCode();\n", " });\n", " }\n", " catch(Exception ex)\n", " {\n", " Console.WriteLine(ex.Message);\n", " }\n", " finally\n", " {\n", "\n", " }\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## 5、IoC容器管理" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### 直接注册IoC" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "/*\n", " 注意：\n", " 1、直接IoC管理：只能一个，不太方便；\n", " 2、可使用.NET 8+ 的 KeyedService, 可以管理多个。 老版只能用服务集合，勉强能用；\n", " 3、把HttpClient 放在多个类中，分别注册使用；不过这样，不如直接使用类型化客户端；\n", "*/\n", "{ // 直接使用\n", " var services = new ServiceCollection();\n", " services.AddSingleton(new HttpClient()\n", " {\n", " //BaseAddress = new Uri(\"https://localhost:5001/\"),\n", " Timeout = TimeSpan.FromSeconds(10),\n", " });\n", "\n", " var client = services.BuildServiceProvider().GetRequiredService();\n", "\n", " var resp = await client.GetAsync(\"https://www.baidu.com\");\n", " resp.EnsureSuccessStatusCode();\n", "\n", " var content = await resp.Content.ReadAsStringAsync();\n", " Console.WriteLine(content.Length);\n", "}\n", "\n", "{ // KeyService: .Net 8+ 才支持的功能\n", " var services = new ServiceCollection();\n", " services\n", " .AddKeyedSingleton(\"HttpClientA\",new HttpClient()\n", " {\n", " BaseAddress = new Uri(\"https://www.baidu.com/\"),\n", " Timeout = TimeSpan.FromSeconds(10),\n", " })\n", " .AddKeyedSingleton(\"HttpClientB\", new HttpClient()\n", " {\n", " BaseAddress = new Uri(\"https://www.qq.com/\"),\n", " Timeout = TimeSpan.FromSeconds(2),\n", " });\n", "\n", " var clientA = services.BuildServiceProvider().GetRequiredKeyedService(\"HttpClientA\");\n", " var responseA = await clientA.GetAsync(\"/\");\n", " responseA.EnsureSuccessStatusCode();\n", " var contentA = await responseA.Content.ReadAsStringAsync();\n", " Console.WriteLine(contentA.Length);\n", "\n", " var clientB = services.BuildServiceProvider().GetRequiredKeyedService(\"HttpClientB\");\n", "\n", " var responseB = await clientB.GetAsync(\"/\");\n", " responseB.EnsureSuccessStatusCode();\n", "\n", " var contentB= await responseB.Content.ReadAsStringAsync();\n", " Console.WriteLine(contentB.Length);\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### HttpClient 多服务类" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "// IoC 多个HttpClient服务类\n", "\n", "public class HttpClientServerA\n", "{\n", " public static HttpClient Client = new HttpClient()\n", " {\n", " BaseAddress = new Uri(\"https://www.baidu.com/\"),\n", " Timeout = TimeSpan.FromSeconds(2),\n", " };\n", "\n", " public int GetBaiduIndexLength()\n", " {\n", " var requestMessage = new HttpRequestMessage(HttpMethod.Get, \"/\");\n", "\n", " var response = Client.Send(requestMessage);\n", "\n", " response.EnsureSuccessStatusCode();\n", "\n", " var s = response.Content.ReadAsStream();\n", " return (int)s.Length;\n", " }\n", "}\n", "\n", "public class HttpClientServerB\n", "{\n", " public static HttpClient Client = new HttpClient()\n", " {\n", " BaseAddress = new Uri(\"https://www.qq.com/\"),\n", " Timeout = TimeSpan.FromSeconds(2),\n", " };\n", "\n", " public int GetBaiduIndexLength()\n", " {\n", " var requestMessage = new HttpRequestMessage(HttpMethod.Get, \"/\");\n", "\n", " var response = Client.Send(requestMessage);\n", "\n", " response.EnsureSuccessStatusCode();\n", "\n", " var s = response.Content.ReadAsStream();\n", " return (int)s.Length;\n", " }\n", "}\n", "\n", "{\n", " var services = new ServiceCollection();\n", " services.AddScoped();\n", " services.AddScoped();\n", "\n", " var provider = services.BuildServiceProvider();\n", "\n", " var clientA = provider.GetService();\n", " var sumA = clientA.GetBaiduIndexLength();\n", " Console.WriteLine($\"A: {sumA}\");\n", "\n", " var clientB = provider.GetService();\n", " var sumB = clientB.GetBaiduIndexLength();\n", " Console.WriteLine($\"A: {sumB}\");\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## 6、客户端工厂管理：IHttpClientFactory(需要结合IoC) `强力推荐`" ] }, { "cell_type": "markdown", "metadata": { "vscode": { "languageId": "polyglot-notebook" } }, "source": [ "使用 IHttpClientFactory 创建和管理 `短期HttpClient` 是官方强力推荐的方式。特别是使用IoC或是 ASP.NET中后台调用其它接口的情况。\n", "\n", "IHttpClientFactory 综合使用了 HttpClient的多种特性：HttpClient的生命周期、HttpClient的配置、HttpClient的拦截器、HttpClient的缓存、HttpClient的依赖注入、Polly等等。\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### 默认客户端" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "从使用推测，设计 IHttpClientFactory 时，重点应该是使用 “命名客户端” 或 “类型化客户端” 而不是默认客户端。 \n", "\n", "只有 AddHttpClient() 扩展方法返回 IServiceCollection；其它相关扩展方法（ AddHttpClient()）均返回 IHttpClientBuilder，明显针对命名客户端。\n", "AddHttpClient() 相当于注册了基本框架；而命名客户端中，名称为空(\"\"或string.Empty)的，相当于默认客户端。\n", "\n", "有一个 名为 `ConfigureHttpClientDefaults` 的 ServiceCollection 对象的扩展方法，用于配置所有HttpClient实例，并且只在初始化时执行一次。如果只使用一个默认客户端的话，可以使用 ConfigureHttpClientDefaults 和 AddHttpClient() 配合使用，也能达到默认客户端的配置效果。 " ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "//方式1：默认客户端\n", "{ \n", " var services = new ServiceCollection();\n", " /*\n", " AddHttpClient() 返回 ServiceCollection，可以继续添加其他客户端。\n", " 其它方法则返回IHttpClientBuilder，后结配置的扩展方法，只能针对当前前端那个命名命令端。\n", " */\n", " services.AddHttpClient();\n", "\n", " var factory = services.BuildServiceProvider().GetRequiredService();\n", "\n", " var client = factory.CreateClient();\n", " //或者\n", " var client2 = factory.CreateClient(\"\");\n", " //或者 内部都是使用CreateClient(string.Empty)，表示默认客户端。\n", " var client3 = factory.CreateClient(string.Empty);\n", "\n", " var response = await client.GetAsync(webApiBaseUrl + \"/api/hello/index\");\n", " response.EnsureSuccessStatusCode();\n", " var data = await response.Content.ReadAsStringAsync();\n", " data.Display();\n", "}\n", "\n", "//方式2：默认客户端 +　默认配置\n", "{ \n", " var services = new ServiceCollection();\n", "\n", " //默认客户端\n", " services.AddHttpClient();\n", "\n", " //配置所有客户端\n", " services.ConfigureHttpClientDefaults(builder => \n", " {\n", " //配置构建器\n", " //builder.AddDefaultLogger();\n", "\n", " //配置客户端\n", " builder.ConfigureHttpClient(c=>\n", " {\n", " c.BaseAddress = new Uri(webApiBaseUrl);\n", " });\n", " });\n", "\n", " var factory = services.BuildServiceProvider().GetRequiredService();\n", " var client = factory.CreateClient();\n", " var response = await client.GetAsync(\"/api/hello/ping\");\n", " response.EnsureSuccessStatusCode();\n", " var data = await response.Content.ReadAsStringAsync();\n", " data.Display();\n", "}\n", "\n", "//方式3(推荐)：默认客户端：直接使用名称为 string.empty 的命名客户端\n", "{\n", " var services = new ServiceCollection();\n", "\n", " //默认客户端\n", " services\n", " .AddHttpClient(string.Empty)\n", " //这样后续的配置，都是针对 string.empty 的客户端，可以使用全部配置功能\n", " .ConfigureHttpClient(c=>c.BaseAddress = new Uri(webApiBaseUrl))\n", " .AddDefaultLogger();\n", "\n", " var factory = services.BuildServiceProvider().GetRequiredService();\n", " var client = factory.CreateClient();\n", " var response = await client.GetAsync(\"/api/hello/ping\");\n", " response.EnsureSuccessStatusCode();\n", " var data = await response.Content.ReadAsStringAsync();\n", " data.Display();\n", "}\n", "\n", "//错误用法\n", "{\n", " var services = new ServiceCollection();\n", "\n", " //默认客户端\n", " services\n", " //没有参数时，导致后面配置不起使用；\n", " //参数必须为 空字符串或string.Empty，后续的配置才能起使用\n", "\n", " .AddHttpClient()\n", " //没有参数时，导致后面配置不起使用\n", " .ConfigureHttpClient(c=>c.BaseAddress = new Uri(webApiBaseUrl))\n", " .AddDefaultLogger();\n", "\n", " var factory = services.BuildServiceProvider().GetRequiredService();\n", " var client = factory.CreateClient();\n", "\n", " try\n", " {\n", " var response = await client.GetAsync(\"/api/hello/ping\");\n", " response.EnsureSuccessStatusCode();\n", " var data = await response.Content.ReadAsStringAsync();\n", " data.Display();\n", " }\n", " catch(InvalidOperationException ex)\n", " {\n", " Console.WriteLine($\"没有参数的配置：AddHttpClient()，因后续配置中，赋值 BaseAddress 不起使用，出现异常：{Environment.NewLine}{ex.Message}\");\n", " }\n", " catch(Exception ex)\n", " {\n", "\n", " Console.WriteLine(ex.Message);\n", " }\n", " finally\n", " {\n", " client.Dispose();\n", " }\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### 默认全局配置" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "ConfigureHttpClientDefaults 扩展方法，添加一个委托，用于配置所有HttpClient实例。只执行一次。" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "//全局配置：所有HttpClient配置\n", "{\n", " var services = new ServiceCollection();\n", " //添加一个委托，用于配置所有HttpClient实例。\n", " //只执行一次，而非每次CreateClient，都会执行一次。\n", " services.ConfigureHttpClientDefaults(builder => \n", " {\n", " //builder.UseSocketsHttpHandler();\n", " //builder.SetHandlerLifetime(TimeSpan.FromMinutes(5));\n", " \n", " builder.ConfigureHttpClient(hc =>\n", " {\n", " hc.BaseAddress = new Uri(webApiBaseUrl);\n", " });\n", "\n", " Console.WriteLine(\"ConfigureHttpClientDefaults 只执行一次！\");\n", " });\n", "\n", " //配置命名客户端\n", " services\n", " .AddHttpClient(\"client_a\")\n", " .ConfigureHttpClient(hc => \n", " {\n", " hc.DefaultRequestHeaders.Add(\"client_a\", \"client_a\");\n", "\n", " //可以覆盖默认配置\n", " //hc.BaseAddress = new Uri(\"http://www.qq.com\");\n", "\n", " Console.WriteLine(\"ConfigureHttpClient 每次 CreateClient 执行一次！\");\n", " });\n", "\n", " \n", " var factory = services.BuildServiceProvider().GetRequiredService();\n", "\n", " //默认客户端\n", " var defaultClient = factory.CreateClient();\n", " var defaultResponse = await defaultClient.GetAsync(\"/api/hello/ping\");\n", " var defaultData = await defaultResponse.Content.ReadAsStringAsync();\n", " Console.WriteLine(defaultData);\n", "\n", " //命名客户端\n", " var namedClient = factory.CreateClient(\"client_a\");\n", " var namedResponse = await namedClient.GetAsync(\"/api/hello/get\");\n", " var namedData = await namedResponse.Content.ReadAsStringAsync();\n", " Console.WriteLine(namedData);\n", "\n", " _ = factory.CreateClient(\"client_a\");\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### 命名客户端（推荐用法）" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "命名客户端，应该是官方推荐的方法。名称为空字符串或string.Empty时，可以为是默认命名客户端，factory.CreateClient()创建的就是这个默认客户端(或者factory.CreateClient(\"\"))。" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "//命名客户端\n", "{\n", " var clientA =\"httpClientA\";\n", " var clientB =\"httpClientB\";\n", "\n", " var services = new ServiceCollection();\n", "\n", " services.AddHttpClient(string.Empty, (provider, client) => \n", " {\n", " client.BaseAddress = new Uri(webApiBaseUrl);\n", " });\n", "\n", " services.AddHttpClient(clientA, (provider, client) => \n", " {\n", " client.BaseAddress = new Uri(webApiBaseUrl);\n", " });\n", "\n", " services.AddHttpClient(clientB, (provider, client) => \n", " {\n", " client.DefaultVersionPolicy = HttpVersionPolicy.RequestVersionOrHigher;\n", " client.BaseAddress = new Uri(webApiBaseUrl);\n", " })\n", " .ConfigureHttpClient(client=>\n", " {\n", " client.Timeout = TimeSpan.FromSeconds(1);\n", " client.DefaultRequestVersion = new Version(1, 1);\n", " });\n", "\n", " var factory = services.BuildServiceProvider().GetRequiredService();\n", "\n", " //name=string.Empty\n", " var defaultClient = factory.CreateClient();\n", " var defaultResponse = await defaultClient.GetAsync(\"/api/hello/ping\");\n", " var defaultData = await defaultResponse.Content.ReadAsStringAsync();\n", " Console.WriteLine(defaultData);\n", "\n", " //name=clientA\n", " var httpClient_a = factory.CreateClient(clientA);\n", " var responseA = await httpClient_a.GetAsync(\"/api/hello/ping\");\n", " var dataA = await responseA.Content.ReadAsStringAsync();\n", " dataA.Display();\n", "\n", " //name=clientB\n", " var httpClient_B = factory.CreateClient(clientB);\n", " var responseB = await httpClient_B.GetAsync(\"/api/hello/ping\");\n", " var dataB = await responseB.Content.ReadAsStringAsync();\n", " dataB.Display();\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### 类型化客户端 （推荐）" ] }, { "cell_type": "markdown", "metadata": { "vscode": { "languageId": "polyglot-notebook" } }, "source": [ "类型化的客户端，两种基本使用方式：\n", "1、可以单独使用(直接IoC容器)\n", "2、与IFactoryHttpClient配合使用(依赖注入),目的是：从统一的工厂配置中获取客户端，作为 HttpClient 类型的实参，传给类型化客户端的构造函数。\n", " 换名话说：从工厂获取HttpClient实例，设置为 类型化客户端类的 HttpClient，在其内部使用。" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "// 类型化客户端 HttpClient\n", "public class HttpClientServiceA\n", "{\n", " public HttpClient Client { get; }\n", " public HttpClientServiceA(HttpClient client)\n", " {\n", " Client = client;\n", " Console.WriteLine(\"HttpClientServiceA => 构造函数执行一次\");\n", " }\n", "\n", " public async Task GetIndexAsync()\n", " {\n", " var response = await Client.GetAsync(\"/api/hello/index\");\n", " var content = await response.Content.ReadAsStringAsync();\n", " return content;\n", " }\n", "}\n", "\n", "public class HttpClientServiceB\n", "{\n", " public HttpClient Client { get; }\n", " public HttpClientServiceB(HttpClient client)\n", " {\n", " Client = client;\n", " Console.WriteLine(\"HttpClientServiceB => 构造函数执行一次\");\n", " }\n", "\n", " public async Task PingAsync()\n", " {\n", " var response = await Client.GetAsync(\"/api/hello/Ping\");\n", " var content = await response.Content.ReadAsStringAsync();\n", " return content;\n", " }\n", "}\n", "\n", "// 方式1(不推荐)：类型化客户端：直接注入IoC,并从中获取实例。优点是范围可以自己选择。\n", "{\n", " Console.WriteLine(\"方式1 -------------------------------------------------------------------\");\n", " var services = new ServiceCollection();\n", " services.AddSingleton(b => \n", " { \n", " return new HttpClientServiceA(new HttpClient(){BaseAddress = new Uri(webApiBaseUrl)});\n", " });\n", " services.AddScoped(b=> \n", " {\n", " return new HttpClientServiceB(new HttpClient(){BaseAddress = new Uri(webApiBaseUrl)});\n", " });\n", "\n", " var builder = services.BuildServiceProvider();\n", " var serverA = builder.GetRequiredService();\n", " var serverB = builder.GetRequiredService();\n", "\n", " var dataA = await serverA.GetIndexAsync();\n", " Console.WriteLine(dataA);\n", "\n", " var dataB = await serverB.PingAsync();\n", " Console.WriteLine(dataB);\n", "\n", " Console.WriteLine(\"========================================================================\");\n", "}\n", "\n", "// 方式2：类型化客户端：AddHttpClient<>() 设置\n", "{\n", " Console.WriteLine(\"方式2 -------------------------------------------------------------------\");\n", " var services = new ServiceCollection();\n", " services\n", " .AddHttpClient()\n", " .ConfigureHttpClient(client=>\n", " {\n", " client.BaseAddress = new Uri(webApiBaseUrl);\n", " });\n", "\n", " services\n", " .AddHttpClient()\n", " .ConfigureHttpClient(client=>\n", " {\n", " client.BaseAddress = new Uri(webApiBaseUrl);\n", " });\n", "\n", " var builder = services.BuildServiceProvider();\n", " var serverA = builder.GetRequiredService();\n", " var serverB = builder.GetRequiredService();\n", "\n", " var dataA = await serverA.GetIndexAsync();\n", " Console.WriteLine(dataA);\n", "\n", " var dataB = await serverB.PingAsync();\n", " Console.WriteLine(dataB);\n", "\n", " Console.WriteLine(\"========================================================================\");\n", "}\n", "\n", "// 方式3：类型化客户端：结合工厂，由工厂从统一配置中提供类型化客户端中使用的HttpClient实例。\n", "{\n", " Console.WriteLine(\"方式3 -------------------------------------------------------------------\");\n", " var services = new ServiceCollection();\n", " services.AddHttpClient(client => \n", " {\n", " client.BaseAddress = new Uri(webApiBaseUrl);\n", " Console.WriteLine(\"HttpClientServiceA => AddHttpClient 执行一次\");\n", " })\n", " .AddTypedClient()\n", " .ConfigureHttpClient(client=>\n", " {\n", " client.Timeout = TimeSpan.FromSeconds(1);\n", " Console.WriteLine(\"HttpClientServiceA => ConfigureHttpClient 执行一次\");\n", " });\n", "\n", " services.AddHttpClient(client => \n", " {\n", " client.BaseAddress = new Uri(webApiBaseUrl);\n", " Console.WriteLine(\"HttpClientServiceB => AddHttpClient 执行一次\");\n", " })\n", " .AddTypedClient()\n", " .ConfigureHttpClient(client=>\n", " {\n", " client.Timeout = TimeSpan.FromSeconds(2);\n", " Console.WriteLine(\"HttpClientServiceB => ConfigureHttpClient 执行一次\");\n", " });\n", "\n", " var builder = services.BuildServiceProvider();\n", "\n", " var serviceA = builder.GetRequiredService();\n", " var serviceB = builder.GetRequiredService();\n", " //每获取一次类型化客户端，都会执行一交。\n", " var serviceB2 = builder.GetRequiredService();\n", "\n", " var dataA = await serviceA.GetIndexAsync();\n", " Console.WriteLine(dataA);\n", "\n", " var dataB = await serviceB.PingAsync();\n", " Console.WriteLine(dataB);\n", "\n", " var dataB2 = await serviceB2.PingAsync();\n", " Console.WriteLine(dataB2);\n", "\n", " Console.WriteLine(\"========================================================================\");\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### 管道配置" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "//管道配置\n", "\n", "//日志中间件(管道类)\n", "public class LoggerDelegatingHandler : DelegatingHandler\n", "{\n", " protected override HttpResponseMessage Send(HttpRequestMessage request, CancellationToken cancellationToken)\n", " {\n", " Console.WriteLine(\"LoggerDelegatingHandler -> Send -> Before\");\n", "\n", " HttpResponseMessage response = base.Send(request, cancellationToken);\n", "\n", " Console.WriteLine(\"LoggerDelegatingHandler -> Send -> After\");\n", "\n", " return response;\n", " }\n", "\n", " protected override async Task SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)\n", " {\n", " Console.WriteLine(\"LoggerDelegatingHandler -> SendAsync -> Before\");\n", "\n", " HttpResponseMessage response = await base.SendAsync(request, cancellationToken);\n", "\n", " Console.WriteLine(\"LoggerDelegatingHandler -> SendAsync -> After\");\n", "\n", " return response;\n", " }\n", "}\n", "\n", "//使用日志中间件\n", "{\n", " var services = new ServiceCollection();\n", "\n", " //先注册\n", " services.AddTransient();\n", "\n", " services.AddHttpClient(string.Empty).ConfigureHttpClient(client =>\n", " {\n", " client.BaseAddress = new Uri(webApiBaseUrl);\n", " })\n", " //配置SocketsHttpHandler\n", " .UseSocketsHttpHandler((handler,provider) =>\n", " {\n", " handler.ConnectTimeout = TimeSpan.FromSeconds(10);\n", " handler.MaxConnectionsPerServer = 100;\n", " handler.UseProxy = false;\n", " handler.UseCookies = true;\n", " handler.EnableMultipleHttp2Connections = true;\n", " handler.SslOptions.RemoteCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true;\n", " })\n", " //使用前先在AddTransient范围注册\n", " .AddHttpMessageHandler()\n", " ;\n", "\n", " var factory = services.BuildServiceProvider().GetService();\n", "\n", " var client = factory.CreateClient();\n", "\n", " var response = await client.GetAsync(\"/api/hello/ping\");\n", " response.EnsureSuccessStatusCode();\n", "\n", " var responseString = await response.Content.ReadAsStringAsync();\n", " Console.WriteLine(responseString);\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### 日志配置" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "默认日志配置，需要先引用 `Microsoft.Extensions.Logging` 和 `Microsoft.Extensions.Logging.Console` 包，进行通用日志配置！" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "//通用日志\n", "{\n", " ILoggerFactory loggerFactory = LoggerFactory.Create(buider =>\n", " {\n", " buider.AddConsole();\n", " });\n", "\n", " ILogger logger = loggerFactory.CreateLogger(\"logger\");\n", " logger.LogInformation(\"直接使用的通用日志!\");\n", "}\n", "\n", "//IoC中使用\n", "{\n", " var services = new ServiceCollection();\n", " services.AddLogging(config =>\n", " {\n", " config.SetMinimumLevel(LogLevel.Information);\n", "\n", " config.AddConsole();\n", " //config.AddSimpleConsole();\n", " //config.AddSystemdConsole();\n", " });\n", "\n", " var serviceProvider = services.BuildServiceProvider();\n", " var loggerFactory = serviceProvider.GetRequiredService();\n", " var logger = loggerFactory.CreateLogger(\"logger\");\n", " logger.LogInformation(\"IoC中使用日志!\");\n", " logger.LogError(\"IoC中的错误日志!\");\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "#### 配置默认日志" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "//配置默认日志(必须有常规日志及级别设置，否则不起使用)\n", "{\n", " var services = new ServiceCollection();\n", "\n", " // 1、配置通用日志\n", " services.AddLogging(config =>\n", " {\n", " //日志级别\n", " config.SetMinimumLevel(LogLevel.Trace);\n", " //config.SetMinimumLevel(LogLevel.Information);\n", "\n", " //日志载体\n", " config.AddConsole();\n", " //config.AddDebug();\n", " //config.AddJsonConsole();\n", " //config.AddSimpleConsole();\n", " //config.AddSystemdConsole();\n", "\n", " });\n", " services\n", " .ConfigureHttpClientDefaults(options =>\n", " {\n", " //2、配置通用日志\n", " options.AddDefaultLogger();\n", " })\n", " .AddHttpClient(String.Empty,c =>\n", " {\n", " c.BaseAddress = new Uri(webApiBaseUrl);\n", " c.DefaultRequestHeaders.Add(\"Authorization\", \"Bearer a.b.c\");\n", " })\n", " //2、或者单独配置此命名客户端日志\n", " .AddDefaultLogger()\n", " ;\n", "\n", " var factory = services.BuildServiceProvider().GetService();\n", " var client = factory.CreateClient(String.Empty);\n", " var response = await client.GetAsync(\"api/hello/index\");\n", "\n", " response.EnsureSuccessStatusCode();\n", "\n", " var content = await response.Content.ReadAsStringAsync();\n", "\n", " Console.WriteLine(content);\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "#### 配置自定义日志" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "[博客](https://www.cnblogs.com/MingsonZheng/p/18013332) 可以参考" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "/* 添加自定义日志记录\n", " 1、可以指定当 HttpClient 启动请求、接收响应或引发异常时记录的内容和方式。可以同时添加多个自定义记录器(控制台、ETW 记录器)，或“包装”和“不包装”记录器。由于其附加性质，可能需要事先显式删除默认的“旧”日志记录。\n", " 要添加自定义日志记录，您需要实现 IHttpClientLogger 接口，然后使用 AddLogger 将自定义记录器添加到客户端。请注意，日志记录实现不应引发任何异常，否则可能会中断请求执行\n", " 2、请求上下文对象\n", " 上下文对象可用于将 LogRequestStart 调用与相应的 LogRequestStop 调用相匹配，以将数据从一个调用传递到另一个调用。 Context 对象由 LogRequestStart 生成，然后传递回 LogRequestStop。这可以是属性包或保存必要数据的任何其他对象。\n", " 如果不需要上下文对象，实现可以从 LogRequestStart 返回 null。\n", " 3、避免从内容流中读取\n", " 例如，如果您打算阅读和记录请求和响应内容，请注意，它可能会对最终用户体验产生不利的副作用并导致错误。例如，请求内容可能在发送之前被消耗，或者巨大的响应内容可能最终被缓冲在内存中。此外，在 .NET 7 之前，访问标头不是线程安全的，可能会导致错误和意外行为。\n", " 4、谨慎使用异步日志记录\n", " 我们期望同步 IHttpClientLogger 接口适用于绝大多数自定义日志记录用例。出于性能原因，建议不要在日志记录中使用异步。但是，如果严格要求日志记录中的异步访问，您可以实现异步版本 IHttpClientAsyncLogger。它派生自 IHttpClientLogger，因此可以使用相同的 AddLogger API 进行注册。\n", " 请注意，在这种情况下，还应该实现日志记录方法的同步对应项，特别是如果该实现是面向 .NET Standard 或 .NET 5+ 的库的一部分。同步对应项是从同步 HttpClient.Send 方法调用的；即使 .NET Standard 表面不包含它们，.NET Standard 库也可以在 .NET 5+ 应用程序中使用，因此最终用户可以访问同步 HttpClient.Send 方法。\n", " 5、包装和不包装记录仪：\n", " 当您添加记录器时，您可以显式设置wrapHandlersPipeline参数来指定记录器是否将被包装。默认不包装。\n", " 在将重试处理程序添加到管道的情况下（例如 Polly 或某些重试的自定义实现），包装和不包装管道之间的区别最为显着。\n", "*/\n", "\n", "// 创建一个简单的控制台日志类\n", "public class SimpleConsoleLogger : IHttpClientLogger\n", "{\n", " public object? LogRequestStart(HttpRequestMessage request)\n", " {\n", " return null;\n", " }\n", "\n", " public void LogRequestStop(object? ctx, HttpRequestMessage request, HttpResponseMessage response, TimeSpan elapsed)\n", " {\n", " Console.WriteLine($\"自定义日志：{request.Method} {request.RequestUri?.AbsoluteUri} - {(int)response.StatusCode} {response.StatusCode} in {elapsed.TotalMilliseconds}ms\");\n", " }\n", "\n", " public void LogRequestFailed(object? ctx, HttpRequestMessage request, HttpResponseMessage? response, Exception e, TimeSpan elapsed)\n", " {\n", " Console.WriteLine($\"自定义日志：{request.Method} {request.RequestUri?.AbsoluteUri} - Exception {e.GetType().FullName}: {e.Message}\");\n", " }\n", "}\n", "\n", "//使用\n", "{\n", " var services = new ServiceCollection();\n", " //1、先注册日志类\n", " services.AddSingleton();\n", "\n", " services\n", " // 全局配置\n", " .ConfigureHttpClientDefaults(options =>\n", " {\n", " })\n", " // 配置到HttpClient\n", " .AddHttpClient(String.Empty,c =>\n", " {\n", " c.BaseAddress = new Uri(webApiBaseUrl);\n", " })\n", " //可选：取消默认日志记录\n", " .RemoveAllLoggers()\n", " //2、配置到HttpClient\n", " .AddLogger()\n", " ;\n", "\n", " var factory = services.BuildServiceProvider().GetService();\n", " var client = factory.CreateClient(String.Empty);\n", " var response = await client.GetAsync(\"api/hello/index\");\n", "\n", " response.EnsureSuccessStatusCode();\n", "\n", " var content = await response.Content.ReadAsStringAsync();\n", "\n", " Console.WriteLine($\"API 影响内容：{content}\");\n", "}\n", "\n", "// 使用上下文的日志类\n", "public class RequestIdLogger : IHttpClientLogger\n", "{\n", " private readonly ILogger _log;\n", "\n", " public RequestIdLogger(ILogger log)\n", " {\n", " _log = log;\n", " }\n", "\n", " private static readonly Action _requestStart = LoggerMessage.Define\n", " (\n", " LogLevel.Information,\n", " EventIds.RequestStart,\n", " \"Request Id={RequestId} ({Host}) started\"\n", " );\n", "\n", " private static readonly Action _requestStop = LoggerMessage.Define\n", " (\n", " LogLevel.Information,\n", " EventIds.RequestStop,\n", " \"Request Id={RequestId} succeeded in {elapsed}ms\"\n", " );\n", "\n", " private static readonly Action _requestFailed = LoggerMessage.Define\n", " (\n", " LogLevel.Error,\n", " EventIds.RequestFailed,\n", " \"Request Id={RequestId} FAILED\"\n", " );\n", "\n", " public object? LogRequestStart(HttpRequestMessage request)\n", " {\n", " var ctx = new Context(Guid.NewGuid());\n", " _requestStart(_log, ctx.RequestId, request.RequestUri?.Host, null);\n", " return ctx;\n", " }\n", "\n", " public void LogRequestStop(object? ctx, HttpRequestMessage request, HttpResponseMessage response, TimeSpan elapsed)\n", " {\n", " _requestStop(_log, ((Context)ctx!).RequestId, elapsed.TotalMilliseconds, null);\n", " }\n", "\n", " public void LogRequestFailed(object? ctx, HttpRequestMessage request, HttpResponseMessage? response, Exception e, TimeSpan elapsed)\n", " {\n", " _requestFailed(_log, ((Context)ctx!).RequestId, null);\n", " }\n", "\n", " public static class EventIds\n", " {\n", " public static readonly EventId RequestStart = new(1, \"RequestStart\");\n", " public static readonly EventId RequestStop = new(2, \"RequestStop\");\n", " public static readonly EventId RequestFailed = new(3, \"RequestFailed\");\n", " }\n", "\n", " record Context(Guid RequestId);\n", "}\n", "\n", "//使用\n", "{\n", " var services = new ServiceCollection();\n", "\n", " services.AddLogging(config =>\n", " {\n", " config.SetMinimumLevel(LogLevel.Trace);\n", " config.AddConsole();\n", " });\n", "\n", " //1、先注册日志类\n", " services.AddSingleton();\n", "\n", " services\n", " // 全局配置\n", " .ConfigureHttpClientDefaults(options =>\n", " {\n", " })\n", " // 配置到HttpClient\n", " .AddHttpClient(String.Empty,c =>\n", " {\n", " c.BaseAddress = new Uri(webApiBaseUrl);\n", " })\n", " //可选：取消默认日志记录\n", " .RemoveAllLoggers()\n", " //2、配置到HttpClient\n", " .AddLogger()\n", " ;\n", "\n", " var factory = services.BuildServiceProvider().GetService();\n", " var client = factory.CreateClient(String.Empty);\n", " var response = await client.GetAsync(\"api/hello/get\");\n", "\n", " response.EnsureSuccessStatusCode();\n", "\n", " var content = await response.Content.ReadAsStringAsync();\n", "\n", " Console.WriteLine($\"API 影响内容：{content}\");\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## 7 工厂 + Polly V8" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "IFactoryHttpClient 与 Polly配合，可轻松实现重试、熔断、降级、限流等功能，本文只是简略的给出常用的使用方法，详情会写在 Polly学习项目中。[Polly 官方参考](https://github.com/App-vNext/Polly/wiki/Polly-and-HttpClientFactory)\n", "使用步骤：\n", "1. 引用 Polly v8 和 Microsoft.Extensions.Http.Polly 包\n", "2. 配置命名客户端\n", "3. 使用 AddTransientHttpErrorPolicy 快捷方法，配置策略\n", "4. 使用其它方式配置，并且可以使用多策略、注册策略、上下文等功能" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### 基础应用" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "使用快捷方法AddTransientHttpErrorPolicy，进行常用功能使用。" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "/*\n", " 便捷应用：AddTransientHttpErrorPolicy() 方法，添加常用瞬时错误重试策略\n", "*/\n", "{\n", " var services = new ServiceCollection();\n", "\n", " services.AddHttpClient(string.Empty)\n", " //配置默认命名客户端\n", " .ConfigureHttpClient(client => \n", " {\n", " client.BaseAddress = new Uri(webApiBaseUrl);\n", " })\n", " //设置Policy错误处理快捷扩展方法\n", " .AddTransientHttpErrorPolicy(builder => builder.WaitAndRetryAsync\n", " (\n", " new[]\n", " {\n", " TimeSpan.FromSeconds(1),\n", " TimeSpan.FromSeconds(2),\n", " TimeSpan.FromSeconds(4),\n", " }\n", " ))\n", " //可以多次调用：设置多个策略\n", " .AddTransientHttpErrorPolicy(builder => builder.RetryAsync(1));\n", " \n", " var factory = services.BuildServiceProvider().GetService();\n", " var content = await factory.CreateClient().GetStringAsync(\"/api/polly8/RandomException\");\n", "\n", " Console.WriteLine($\"响应内容：{content}\");\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### 使用通过传统 Polly 语法配置的任何策略" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "使用 AddPolicyHandler 方法及其重载也可用于接受任何 IAsyncPolicy ，因此可以定义和应用任何类型的策略：可以指定要处理的内容和处理方式。" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "dotnet_interactive": { "language": "csharp" }, "polyglot_notebook": { "kernelName": "csharp" }, "vscode": { "languageId": "polyglot-notebook" } }, "outputs": [], "source": [ "/*\n", " 传统方式配置Polly策略\n", "*/\n", "//创建策略\n", "{\n", " var services = new ServiceCollection();\n", "\n", " //重试策略\n", " var retryePolicy = Policy\n", " .Handle()\n", " .OrResult(response => \n", " {\n", " return response.StatusCode == System.Net.HttpStatusCode.Created;\n", " })\n", " .WaitAndRetryAsync(new TimeSpan[]{TimeSpan.FromSeconds(1), TimeSpan.FromMilliseconds(2)});\n", " //调用\n", " services\n", " .AddHttpClient(string.Empty)\n", " .AddPolicyHandler(retryePolicy);\n", "\n", " //超时策略\n", " var timeoutPolicy = Policy.TimeoutAsync(10);\n", " services\n", " .AddHttpClient(\"timeoutPolicy\")\n", " .AddPolicyHandler(timeoutPolicy);\n", " \n", " /* 普通策略转换\n", " 所有通过 HttpClient 的调用都返回 HttpResponseMessage 因此配置的策略必须是 IAsyncPolicy \n", " 通过简单、便捷的 AsAsyncPolicy()方法，将非通用策略 IAsyncPolicy 转换为 IAsyncPolicy \n", " */\n", " var timeoutPolicy2 = Policy.TimeoutAsync(2);\n", "\n", " services\n", " .AddHttpClient(\"timeoutPolicy2\")\n", " //转换通用策略\n", " .AddPolicyHandler(timeoutPolicy2.AsAsyncPolicy());\n", "}\n", "\n", "//示例\n", "{\n", " //创建策略\n", " var policy = Policy.RateLimitAsync(3,TimeSpan.FromSeconds(10));\n", "\n", " //使用\n", " var services = new ServiceCollection();\n", "\n", " services.AddHttpClient(string.Empty)\n", " .ConfigureHttpClient(client => \n", " {\n", " client.BaseAddress = new Uri(webApiBaseUrl);\n", " })\n", " .AddTransientHttpErrorPolicy\n", " (\n", " builder => builder.WaitAndRetryAsync\n", " (\n", " new[]\n", " {\n", " TimeSpan.FromSeconds(1),\n", " TimeSpan.FromSeconds(2),\n", " TimeSpan.FromSeconds(4)\n", " }\n", " )\n", " )\n", " .AddPolicyHandler(policy);\n", " try\n", " {\n", " var factory = services.BuildServiceProvider().GetService();\n", " var content = await factory.CreateClient().GetStringAsync(\"/api/polly8/RandomException\");\n", " Console.WriteLine($\"响应内容：{content}\");\n", " }\n", " catch(Exception ex)\n", " {\n", " Console.WriteLine($\"未处理的异常：{ex.Message}\");\n", " }\n", "}" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### 应用多个策略" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### 动态选择策略" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### 从注册表中选择策略" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## 8、综合管理：工厂 + 类型化客户端 ＋ 请求管道 + Polly(默认使用 连接池和IoC容器)" ] } ], "metadata": { "kernelspec": { "display_name": ".NET (C#)", "language": "C#", "name": ".net-csharp" }, "language_info": { "name": "python" }, "polyglot_notebook": { "kernelInfo": { "defaultKernelName": "csharp", "items": [ { "aliases": [], "name": "csharp" } ] } } }, "nbformat": 4, "nbformat_minor": 2 }