Using HttpClientFactory to manage HttpClient instances

.NET provides the HttpClient class for sending HTTP requests. However, there is some confusion when using it. In the past, many developers would misuse the using statement to create a HttpClient instance, as it implements the IDisposal interface. This is not recommended, as the HttpClient class is designed to be reused for multiple requests. Creating a new instance for each request can exhaust the local socket ports.

To solve this problem, Microsoft introduced the IHttpClientFactory interface in ASP.NET Core 2.1. This interface simplifies the management of HttpClient instances. It allows us to use dependency injection to inject HttpClient instances into the application without worrying about the life cycle of the HttpClient instances. In this section, we will introduce how to use the IHttpClientFactory interface to manage HttpClient instances.

You can find the sample application for this section in the samples/chapter15/HttpClientDemo...