IHttpClientFactory in ASP.NET Core: a better way to make the HTTP request

IHttpClientFactory is an interface in the System.Net.Http namespace. Which is a factory abstraction for components to create an HttpClient instance with a custom configuration.

Advantages

1. It provides a central location for naming and configuring logical HttpClient instances.
2. It provides extensions for Polly-based middleware for HttpClient.
3. Avoid common DNS problems by managing HttpClient lifetimes.

Http request without IHttpClientFactory (Wrong way)

There are some drawbacks to creating HttpClient multiple times. Here is a detailed article explaining just that. There are many reasons to avoid following code. First and foremost it reduces maintainability, it creates Socket Exhaustion in multiple HTTP call cases, and it is just a boilerplate code.

Ways to use IHttpClientFactory

1. Basic usage (Setup services.AddHttpClient() in Startup.cs, usector DI to load Factory & use factory.CreateClient())
2. Named clients
3. Typed clients

Here I’m going to explain Named & Type clients with examples…

Named Clients

IHttpClientFactory has CreateClient(String) method and CreateClient(HttpClientFactory) extension method to create HttpClient instance.

Step 1: Setup HttpClient configuration in Startup.ConfigureService

Please do configure base properties in Startup. You can always change the config. at the time of the actual call.

Step 2: Use Dependency Injection for IHttpClientFactory

Implement Dependency Injection at the constructor & use the IHttpClientFactory instance in the controller.

Step 3: CreateClient using named type

Here you create a client using an already configured factory name. Now configure additional properties for HttpCient as per your need & lastly actual HTTP call handle response.

Typed Client

To Create Typed Client We Can create a Separate service that uses DI to create HttpClient and internally handle the creation of IHttpClientFactory.

Step 1: Create Service class

Create Interface and implement it in GithubService class. We have used DI of HttpClient and IHttpClientFactory creation will be internally managed. Make sure to create a private HttpClient field.

Step 2: Call the Service

Step 3: Setup Service DI in Startup.ConfigureService

Same as the Named client we can set up all common headers, and base address in the ConfigureServices method but the major difference between Named and Typed clients is that we use separate service classes to manage HttpClient calls.

Bonus

To check the socket info use the following command for windows os

netstat -ano | findstr 127.0.0.1:49960

That’s all you need to do. Easy peasy right? I hope you find something useful.

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For more info check out official docs here & here