MVC patterns make for quick and easy development in .NET Core. This week, I'm switching over to an API servicing a React application, and there are a couple of small differences in getting started with serving up API endpoints:

ApiController Attribute

In MVC, all we needed to setup a controller was inherit from the controller class:

namespace BulkyBookWebDotNet6MVC.Controllers
{
    public class CategoryController : Controller
    {
    . . .
    }
}

For API's, we need to go up the family tree to ControllerBase, which controller inherits from:

namespace BulkyBookWebDotNet6MVC.Controllers
{
    public class CategoryController : ControllerBase
    {
    . . .
    }
}

Attributes

In addition, we need a few different attributes:

[ApiController]
[Route("[controller]")]
public class BookController : ControllerBase
{
    . . .
}

[ApiController] will give goodies specific to APIs, such as specifying routes and more detailed error responses.

Since we have to specify routes, we're doing so with the next attribute [Route("[controller]")] We're defaulting to the controller based routing, but we could just as well define our own route such as [Route("/users")]

Return

Of course, since we're working with an API returning data and not a View from an MVC, the return methods will be slightly different. [ApiController] provides methods that are analogous to Status codes:

if (BookFromDb == null)
{
    // Status: 404
    return NotFound();
}

// Status: 200 with created object
return Ok(BookFromDb);

And that should be enough to get started! More details are available on MSDN.