Creating Web API background service

In ASP.NET Core we can implement background tasks, or Hosted Services, that aid desired logic of a particular application.

Previously I wrote about one potential use case of such background task here.

Since .NET Core 2.0 we can use IHostedService interface to easily implement hosted services for our applications. In the context of the given example I’m using the BackgroundService base class that implements the IHostedService interface. BackgroundService is located in the Microsoft.Extensions.Hosting package, which comes pre-installed when creating a new .NET Core Web API project.

To create a background service in Web API from scratch, the first step is to create the desired background service class and inherit from the BackgroundService base class and implement the necessary ExecuteAsync method.

public class ExampleService : BackgroundService
{
    protected override Task ExecuteAsync(CancellationToken stoppingToken)
    {
        throw new NotImplementedException();
    }
}

Here within ExecuteAsync we can write all required logic for the new background service.

In order for it to register to Host as a background task, we have to register it through AddHostedService method in Startup class.

var builder = WebApplication.CreateBuilder(args);
void ConfigureServices()
{
    builder.Services.AddHostedService<ExampleService>();
}

More detailed info about IHostedService here: https://learn.microsoft.com/en-us/dotnet/architecture/microservices/multi-container-microservice-net-applications/background-tasks-with-ihostedservice