网站没有收录了,网站特色页面建设,外网设计素材网站,汽车推广方式有哪些ASP.Net Core 是一个开源的#xff0c;跨平台的#xff0c;轻量级模块化框架#xff0c;可用它来构建高性能的Web程序#xff0c;这篇文章我们将会讨论如何在 ASP.Net Core 中使用 HttpClientFactory。为什么要使用 HttpClientFactory 可以用 HttpClientFactory 来集中化管… ASP.Net Core 是一个开源的跨平台的轻量级模块化框架可用它来构建高性能的Web程序这篇文章我们将会讨论如何在 ASP.Net Core 中使用 HttpClientFactory。为什么要使用 HttpClientFactory 可以用 HttpClientFactory 来集中化管理 HttpClient工厂提供了对 HttpClient 的创建配置和调度值得一提的是HttpClient 一直都是 Http 请求业务方面的一等公民。HttpClient 虽好但它有一些缺点创建太多的 HttpClient 是一种低效的行为因为当一个新客户端连接到远程 Server 时你的应用程序还需要承担着重连远程 Server 的开销。如果每一个 request 都创建一个 HttpClient当应用程序负载过大 Socket 必将耗尽比如默认情况下 HttpClient 会维持至少4分钟的 Connection 连接。所以推荐的做法是创建一个可供复用的共享式 HttpClient 实例如果你要打破沙锅问到低的话即使是创建共享式的 HttpClient 也会有很多问题比如它会无视 DNS 缓存生效那怎么办呢可以用 .NET Core 2.1 引入的 HttpClientFactory 来解决此问题。。。用它来统一化的高效管理 HttpClient。使用 HttpClientFactory HttpClientFactory 有两种使用方式。NamedClientTypedClient所谓的 NamedClient 就是注册带有标记的 HttpClient 到 HttpClientFactory 工厂中下面的代码展示了一个名为 IDGCustomApi 的 HttpClient 的工厂注册。// This method gets called by the runtime. Use this method to add services to the container.public void ConfigureServices(IServiceCollection services){services.AddHttpClient(IDGCustomApi, client {client.BaseAddress new Uri(https://localhost:6045/);client.DefaultRequestHeaders.Add(Accept, application/json);client.DefaultRequestHeaders.Add(User-Agent, IDG);});services.AddControllers();}所谓的 TypedClient 就是注册一个你自定义的 HttpClient我想你肯定有点懵逼了没关系我现在就来自定义 HttpClient 然后通过 AddHttpClient() 注册到容器中。public class CustomHttpClient{public HttpClient Client { get; }public CustomHttpClient(HttpClient client){Client client;}}public class Startup{// This method gets called by the runtime. Use this method to add services to the container.public void ConfigureServices(IServiceCollection services){services.AddHttpClientCustomHttpClient(client client.BaseAddress new Uri(https://localhost:6045/));services.AddControllers();}}注入 Controller 为了能够在 Controller 中使用可以将 IHttpClientFactory 通过构造函数方式进行注入参考如下代码[ApiController][Route([controller])]public class WeatherForecastController : ControllerBase{private IHttpClientFactory httpClientFactory;public WeatherForecastController(ILoggerWeatherForecastController logger, IHttpClientFactory httpClientFactory){this.httpClientFactory httpClientFactory;}[HttpGet]public async Taskstring Get(){var httpClient httpClientFactory.CreateClient(IDGCustomApi);string html await httpClient.GetStringAsync(http://bing.com);return html;}}从 IHttpClientFactory 的默认实现 DefaultHttpClientFactory 的源码也可以看出,httpClient 所关联的 HttpMessageHandler 和 Options 都被工厂跟踪和管控。internal class DefaultHttpClientFactory : IHttpClientFactory, IHttpMessageHandlerFactory{public HttpClient CreateClient(string name){if (name null){throw new ArgumentNullException(name);}HttpMessageHandler handler CreateHandler(name);HttpClient httpClient new HttpClient(handler, disposeHandler: false);HttpClientFactoryOptions httpClientFactoryOptions _optionsMonitor.Get(name);for (int i 0; i httpClientFactoryOptions.HttpClientActions.Count; i){httpClientFactoryOptions.HttpClientActions[i](httpClient);}return httpClient;}public HttpMessageHandler CreateHandler(string name){if (name null){throw new ArgumentNullException(name);}ActiveHandlerTrackingEntry value _activeHandlers.GetOrAdd(name, _entryFactory).Value;StartHandlerEntryTimer(value);return value.Handler;}}译文链接https://www.infoworld.com/article/3276007/how-to-work-with-httpclientfactory-in-aspnet-core.html
