How is request routing implemented in a controller?

In ASP.NET Core controllers, request routing is implemented using routing attributes or route configuration in Startup.

1. Routing attributes — are applied directly to controllers and methods:

[Route("api/[controller]")]
public class ProductsController : ControllerBase
{
    [HttpGet("{id}")]
    public IActionResult GetProduct(int id)
    {
        // logic
    }
}

Here, requests like api/products/5 will be handled by the GetProduct method.

2. Conventional routing — is set in the application settings:

app.UseEndpoints(endpoints =>
{
    endpoints.MapControllerRoute(
        name: "default",
        pattern: "{controller=Home}/{action=Index}/{id?}");
});

Thus, routing connects URL requests to specific controller methods, allowing handling of various HTTP requests (GET, POST, etc.) on specified paths.