src/libraries/Microsoft.Extensions.Http/src/PACKAGE.md
Microsoft.Extensions.Http package provides AddHttpClient extension methods for IServiceCollection, IHttpClientFactory interface and its default implementation. This provides the ability to set up named HttpClient configurations in a DI container and later retrieve them via an injected IHttpClientFactory instance.
HttpClient configurations for applications that use DI via AddHttpClient extension method.HttpClientFactory caches HttpMessageHandler instances per configuration name, which allows to reuse resources between HttpClient instances to avoid port exhaustion.HttpClientFactory manages lifetime of HttpMessageHandler instances and recycles connections to track DNS changes.Note that lifetime management of HttpClient instances created by HttpClientFactory is completely different from instances created manually. The strategies are to use either short-lived clients created by HttpClientFactory or long-lived clients with PooledConnectionLifetime set up. For more information, see the HttpClient lifetime management section in the conceptual docs and Guidelines for using HTTP clients.
builder.Services.AddHttpClient("foo"); // adding an HttpClient named "foo" with a default configuration
builder.Services.AddHttpClient("example", c => c.BaseAddress = new Uri("https://www.example.com")) // configuring HttpClient itself
.AddHttpMessageHandler<MyAuthHandler>() // adding additional delegating handlers to form a message handler chain
.ConfigurePrimaryHttpMessageHandler(b => new HttpClientHandler() { AllowAutoRedirect = false }) // configuring primary handler
.SetHandlerLifetime(TimeSpan.FromMinutes(30)); // changing the handler recycling interval
public class MyService
{
public MyService(IHttpClientFactory httpClientFactory)
{
_httpClientFactory = httpClientFactory; // injecting the factory
}
private Task<string> GetExampleAsync(Uri uri, CancellationToken ct)
{
HttpClient exampleClient = _httpClientFactory.CreateClient("example"); // creating the client for the specified name
return exampleClient.GetStringAsync(uri, ct); // using the client
}
}
The main types provided by this library are:
IHttpClientFactoryIHttpMessageHandlerFactoryHttpClientFactoryServiceCollectionExtensionsAddHttpClient extension method API docMicrosoft.Extensions.Http is released as open source under the MIT license. Bug reports and contributions are welcome at the GitHub repository.