在单例服务中使用HttpClientFactory是不是有错？

Question

我读了这篇关于 HttpClientFactory 的文章。但我找不到我的问题的答案。在单例服务中使用 HttpClientFactory 将请求发送到某个地方是不是不好的方法？

我的程序.cs：

builder.Services.AddSingleton<TestService>();
builder.Services.AddTransient<HttpRequestDelegatingHandler>();


builder.Services.AddHttpClient("test", client =>
{
    client.BaseAddress = new Uri("https://jsonplaceholder.typicode.com");
}).AddHttpMessageHandler<HttpRequestDelegatingHandler>();

我的测试服务：

public class TestService
{
    public Guid InstanceId { get; } = Guid.NewGuid();

    private readonly **IHttpClientFactory _factory;**
    private readonly ILogger<TestController> _logger;

     public TestService(IHttpClientFactory factory, ILogger<TestController> logger)
    {
        **_factory = factory;**
        _logger = logger;
    }

    public async Task<string> GetAsync()
    {
        // Get the scoped service's ID
        _logger.LogInformation("Service ID in controller {InstanceId}", InstanceId);

        // Retrieve an instance of the test client, and send a request
        var client = _factory.CreateClient("test");
        var result = await client.GetAsync("posts");

        // Just return a response, we're not interested in this bit for now
        result.EnsureSuccessStatusCode();
        return await result.Content.ReadAsStringAsync();
    }
} 

我创建了一个委托处理程序来了解发生了什么，但我没有注意到任何问题。

Answer 1

在

IHttpClientFactory

服务中使用

Singleton

是可以的，顺便说一句，客户端工厂创建的所有

HttpClient

实例都应该是

short-lived

，那么最好使用

using

语句，例如这个：

public async Task<string> GetAsync()
    {
        //...

        // make sure the httpclient will be disposed
        using var client = _factory.CreateClient("test");
        var result = await client.GetAsync("posts");

        // ...
    }