ASP.NET Core–Mark a web api as deprecated

Versioning of your API’s in ASP.NET Core is easy thanks to the Microsoft.Aspnetcore.Mvc.Versioning nuget package. It allows us to implement versioning with a few configuration lines.

After installing the Nuget you should update the ConfigureServices() method in Startup.cs:

	public void ConfigureServices(IServiceCollection services)
	{
	services.AddControllers();
	services.AddApiVersioning();
	}

view raw ConfigureServices.cs hosted with ❤ by GitHub

Now you can add the [ApiVersion] attribute on your controller:

	[ApiController]
	[Route("api/[controller]")]
	[ApiVersion("1.0")]
	public class ExampleController : ControllerBase
	{
	}

view raw VersionedController.cs hosted with ❤ by GitHub

If you now have multiple versions of your api, you can decide which version to use by adding an ?api-version=1.0 at the end of your url.

So far nothing new. A feature I only discovered recently is that you can also flag an API as deprecated.  Therefore you need to set an additional Deprecated property on the attribute:

	[ApiController]
	[Route("api/[controller]")]
	[ApiVersion("1.0",Deprecated = true)]
	public class ExampleController : ControllerBase
	{
	}

view raw DeprecatedVersionController.cs hosted with ❤ by GitHub

When a client now calls the deprecated API, an extra response header ‘api-deprecated-versions’ is returned:

api-deprecated-versions: 1.0