c# - 类型化 HttpClient 与 IHttpClientFactory

Question

下面2种设置HttpClient的场景有什么区别吗？
我应该更喜欢一个吗？
输入客户端:

public class CatalogService 
{
    private readonly HttpClient _httpClient;
    
    public CatalogService(HttpClient httpClient) {
        _httpClient = httpClient;
    }
    
    public async Task<string> Get() {
        var response = await _httpClient.GetAsync();
        ....
    }
    
    public async Task Post() {
        var response = await _httpClient.PostAsync();
        ...
    }
}
// Startup.cs
//Add http client services at ConfigureServices(IServiceCollection services)
services.AddHttpClient<ICatalogService, CatalogService>();

IHttpClientFactory:

public class CatalogService 
{
    private readonly IHttpClientFactory _factory;
    
    public CatalogService(IHttpClientFactory factory) {
        _factory = factory;
    }
    
    public async Task<string> Get() {
        var response = await _factory.CreateClient().GetAsync();
        ....
    }
    
    public async Task Post() {
        var response = await _factory.CreateClient().PostAsync();
        ...
    }
}
// Startup.cs
//Add http client services at ConfigureServices(IServiceCollection services)
services.AddHttpClient();
```

Answer 1

IMO，我会路过HttpClient .原因是，

KISS原则 - 什么 CatalogService真正需要的是HttpClient .服务不关心如何获得客户。

单一职责原则 (SRP) - 假设明天你必须保留两个 CatalogService 的实例向两个不同的端点发送请求，

您可以传入 IHttpClientFactory并在内部实现路由 CatalogService ，但这会破坏 SRP。

或者，您可以创建一个 CatalogServiceFactory .那家工厂得到IHttpClientFactory传入并在内部实现路由。这也称为关注点分离。