Conventional Routing in ASP.NET Core API

Question

Problem:

I'm creating an API Application with NET Core 3.1. I'd like to avoid to set route attribute over every ApiControllers and Actions. I tryed a lot of combinations over UseEndpoints to set a conventional route, but i'm failing.

With some configuration I can't get the Api working, with some others I get this exception during startup:

InvalidOperationException: Action 'ApiIsWorking' does not have an attribute route. Action methods on controllers annotated with ApiControllerAttribute must be attribute routed.

How can i set the startup.cs to auto map controllers with their class name and actions with their method name?

Thank you!

Some code:

startup.cs

...
services.AddControllers()
...

app.UseHttpsRedirection()
   .UseRouting()
   .UseAuthentication()
   .UseEndpoints(endpoints => ?? )
   .UseCoreHttpContext()
   .UseServerConfiguration();

controller.cs

[ApiController]
public class BaseAPI : ControllerBase 
{
        [HttpGet]
        public string ApiIsWorking()
        {
            return "API is working!";
        }
}

Solution:

As Reza Aghaei says in the solution, the error was to add the ApiController attribute. After I removed it, the command UseEndpoints start to work.

My mistake was to add the attribute to be able to recognize which classes should be exposed via API. It wasn't necessary because UseEndpoints maps only the classes that inherit from ControllerBase.

Warning:

1) Conventional Routing require [FromBody] attribute in actions params.

2) I highlight Zinov's response about conventional routing problems with Swashbuckle in .NET Core

Answer 1

To have conventional routing for your controllers and action, you need to remove [ApiController] attribute and [Route] attribute from your controller and actions and setup route in UseEndpoints.

It's already mentioned in the documentations:

The [ApiController] attribute makes attribute routing a requirement.

Actions are inaccessible via conventional routes defined by UseEndpoints, UseMvc, or UseMvcWithDefaultRoute in Startup.Configure.

Example

This is the working setup that I have for Startup:

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }
    public IConfiguration Configuration { get; }
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllersWithViews();
    }
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Home/Error");
        }
        app.UseStaticFiles();
        app.UseRouting();
        app.UseAuthorization();
        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllerRoute(
                name: "default",
                pattern: "{controller=Home}/{action=Index}/{id?}");
        });
    }
}

And a sample API controller:

public class ValuesController : ControllerBase
{
    // values/getall
    [HttpGet]
    public IEnumerable<string> GetAll()
    {
        return new string[] { "value1", "value2" };
    }

    // values/getitem/1
    [HttpGet]
    public string GetItem(int id)
    {
        return "value";
    }
}

Answer 2

Have you tried this?

app.UseEndpoints(endpoints => { endpoints.MapControllers(); });