ASP.NET Core-通过HttpClientFactory使用HttpClient
概述:
在.NET Framwork中使用HttpClient直接这样使用 using(var client = new HttpClient()){} ,高并发时频繁创建socket,连接来不及释放,socket被耗尽,就会出现问题。
所以不用频繁创建HttpClient对象,要复用,可以设置成静态,并且设置成长连接,我之前的教程有介绍。这样使用有一点问题是DNS更新会失效
在Core中使用HttpClientFactory创建HttpClient,目的也是复用HttpClient。顾名思义 HttpClientFactory 就是 HttpClient 的工厂,内部已经帮我们处理好了对 HttpClient 的管理,不需要我们人工进行对象释放,同时,支持自定义请求头,支持DNS更新等等等。
HttpClientFactory使用方法:
用法1,直接使用HttpClientFactory
1、在startup中注册
public void ConfigureServices(IServiceCollection services) { //other codes services.AddHttpClient("client_1",config=> //这里指定的 name=client_1 ,可以方便我们后期服用该实例 { config.BaseAddress= new Uri("http://client_1.com"); config.DefaultRequestHeaders.Add("header_1","header_1"); }); services.AddHttpClient("client_2",config=> { config.BaseAddress= new Uri("http://client_2.com"); config.DefaultRequestHeaders.Add("header_2","header_2"); }); services.AddHttpClient(); }
2、Controller中使用
public class TestController : ControllerBase { private readonly IHttpClientFactory _httpClient; public TestController(IHttpClientFactory httpClient) { _httpClient = httpClient; } public async Task<ActionResult> Test() { var client = _httpClient.CreateClient("client_1"); //复用在 Startup 中定义的 client_1 的 httpclient var result = await client.GetStringAsync("/page1.html"); var client2 = _httpClient.CreateClient(); //新建一个 HttpClient var result2 = await client.GetStringAsync("http://www.site.com/XXX.html"); return null; } }
用法2,自定义类封装HttpClient
1、自定义类封装HttpClient
public interface ISampleClient { Task<string> GetData(); } public class SampleClient : ISampleClient { private readonly HttpClient _client; public SampleClient(IHttpClientFactory httpClientFactory) { var httpClient = httpClientFactory.CreateClient(); httpClient.BaseAddress = new Uri("https://www.taobao.com/"); //httpClient.DefaultRequestHeaders.Add("Accept", "application/json"); //httpClient.DefaultRequestHeaders.Add("User-Agent", "HttpClientFactory-Sample"); _client = httpClient; } public async Task<string> GetData() { return await _client.GetStringAsync("/"); } }
2、Startup中注册SampleClient
services.AddHttpClient<ISampleClient, SampleClient>();
3、调用
public class ValuesController : Controller { private readonly ISampleClient _sampleClient;; public ValuesController(ISampleClient sampleClient) { _sampleClient = sampleClient; } [HttpGet] public async Task<ActionResult> Get() { string result = await _sampleClient.GetData(); return Ok(result); } }
参考:https://blog.zhuliang.ltd/2019/02/net-core/HttpClient-HttpClientFactory-InNetCore.html
参考:
未完待续...
相关推荐
创建一个 HttpClient 实例,这个实例需要调用 Dispose 方法释放资源,这里使用了 using 语句。接着调用 GetAsync,给它传递要调用的方法的地址,向服务器发送 Get 请求。