Web API in ASP.NET Core

In this post I’ll talk about the Web API in ASP.NET Core and how we can implement a Restful service with this new framework.

One of the main difference in ASP.NET Core is that Web API have an unified class with the classic MVC Controllers.

So the declaration of a Web API in ASP.NET Core is look like this:

public class PostController : Controller
{
}

The attribute of the actions verbs is pretty similar to MVC 5.

We can define the controller route as well and we can do that with the Route attribute:

[Route("api/[controller]")]
public class PostController : Controller
{
}

We can implement an action in the same way as the Web API 2:

[HttpGet("{offset}", Name = "GetPost")]
 public IActionResult Get(int offset)
 {
 var result = _postService.GetPosts(offset, true);

return Ok(result);
 }

With the HttpGet attribute we can specify the verb of the method, the parameters and the action url.

So far so good, now there is the last question about this topic, that is the content negotiation.

Since ASP.NET Core MVC and Web API frameworks are unified, with the attribute Produces we can define the response content type for the controllers.

So, if we want to return a content type in json format, we need to apply this attribute:

[Produces("application/json")]
[Route("api/[controller]")]
public class PostController : Controller
{
}

With this attribute the content type of the request will be application/json, otherwise the controller will returns a response 415 – Unsupported media type.

The source code of the topic is here.