ASP.Net Core Web API convention-based routing?

Question

What am I missing that I'm greeted with a 404 for this controller? I really don't want to use attribute-based routing. I also don't want action to be part of any URIs.

I'm using Visual Studio 2017 and .Net Core 1.1.

TestController.cs

using System;
using Microsoft.AspNetCore.Mvc;

namespace Foo.Controllers
{
    public class TestController : Controller
    {
        public long Get() => DateTimeOffset.Now.ToUnixTimeSeconds();
    }
}

Note that this works with a [Route("api/Test")] attribute. But I don't want to use attribute-based routing. And as soon as I take that attribute off, I get 404s.

Startup.cs

namespace Foo
{
    public class Startup
    {
        public Startup(IHostingEnvironment env)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
                .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
                .AddEnvironmentVariables();
            Configuration = builder.Build();
        }

        public IConfigurationRoot Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            // Add framework services.
            services.AddMvc();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            loggerFactory.AddConsole(Configuration.GetSection("Logging"));
            loggerFactory.AddDebug();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "api/{controller}/{id?}"
                    );
            });
        }
    }
}

Note there's also some stuff in here for Autofac/DI, but I took that out to remove the distraction.

Debug output from a request

Application Insights Telemetry (unconfigured): {"name":"Microsoft.ApplicationInsights.Dev.Message","time":"2017-03-10T14:18:01.3308908Z","tags":{"ai.internal.sdkVersion":"aspnet5c:2.0.0","ai.operation.id":"0HL37O0HBESDL","ai.application.ver":"1.0.0.0"},"data":{"baseType":"MessageData","baseData":{"ver":2,"message":"Request starting HTTP/1.1 GET http://localhost:50129/api/test","severityLevel":"Information","properties":{"DeveloperMode":"true","Host":"localhost:50129","AspNetCoreEnvironment":"Development","CategoryName":"Microsoft.AspNetCore.Hosting.Internal.WebHost","Path":"/api/test","Protocol":"HTTP/1.1","Method":"GET","Scheme":"http"}}}}
Microsoft.AspNetCore.Hosting.Internal.WebHost:Information: Request starting HTTP/1.1 GET http://localhost:50129/api/test  
Application Insights Telemetry (unconfigured): {"name":"Microsoft.ApplicationInsights.Dev.Message","time":"2017-03-10T14:18:01.3633954Z","tags":{"ai.cloud.roleInstance":"Desktop","ai.internal.sdkVersion":"aspnet5c:2.0.0","ai.location.ip":"::1","ai.operation.id":"0HL37O0HBESDM","ai.application.ver":"1.0.0.0","ai.internal.nodeName":"Desktop","ai.operation.name":"GET /api/test"},"data":{"baseType":"MessageData","baseData":{"ver":2,"message":"Request successfully matched the route with name 'default' and template 'api/{controller}/{id?}'.","severityLevel":"Verbose","properties":{"DeveloperMode":"true","AspNetCoreEnvironment":"Development","CategoryName":"Microsoft.AspNetCore.Routing.RouteBase","RouteName":"default","{OriginalFormat}":"Request successfully matched the route with name '{RouteName}' and template '{RouteTemplate}'.","RouteTemplate":"api/{controller}/{id?}"}}}}
Application Insights Telemetry (unconfigured): {"name":"Microsoft.ApplicationInsights.Dev.Message","time":"2017-03-10T14:18:01.3663952Z","tags":{"ai.cloud.roleInstance":"Desktop","ai.internal.sdkVersion":"aspnet5c:2.0.0","ai.location.ip":"::1","ai.operation.id":"0HL37O0HBESDM","ai.application.ver":"1.0.0.0","ai.internal.nodeName":"Desktop","ai.operation.name":"GET /api/test"},"data":{"baseType":"MessageData","baseData":{"ver":2,"message":"No actions matched the current request","severityLevel":"Verbose","properties":{"DeveloperMode":"true","AspNetCoreEnvironment":"Development","CategoryName":"Microsoft.AspNetCore.Mvc.Internal.MvcRouteHandler","{OriginalFormat}":"No actions matched the current request"}}}}
Application Insights Telemetry (unconfigured): {"name":"Microsoft.ApplicationInsights.Dev.Message","time":"2017-03-10T14:18:01.3693962Z","tags":{"ai.cloud.roleInstance":"Desktop","ai.internal.sdkVersion":"aspnet5c:2.0.0","ai.location.ip":"::1","ai.operation.id":"0HL37O0HBESDM","ai.application.ver":"1.0.0.0","ai.internal.nodeName":"Desktop","ai.operation.name":"GET /api/test"},"data":{"baseType":"MessageData","baseData":{"ver":2,"message":"Request did not match any routes.","severityLevel":"Verbose","properties":{"DeveloperMode":"true","AspNetCoreEnvironment":"Development","CategoryName":"Microsoft.AspNetCore.Builder.RouterMiddleware","{OriginalFormat}":"Request did not match any routes."}}}}
Application Insights Telemetry (unconfigured): {"name":"Microsoft.ApplicationInsights.Dev.Message","time":"2017-03-10T14:18:01.3753962Z","tags":{"ai.cloud.roleInstance":"Desktop","ai.internal.sdkVersion":"aspnet5c:2.0.0","ai.location.ip":"::1","ai.operation.id":"0HL37O0HBESDM","ai.application.ver":"1.0.0.0","ai.internal.nodeName":"Desktop","ai.operation.name":"GET /api/test"},"data":{"baseType":"MessageData","baseData":{"ver":2,"message":"Connection id \"0HL37O0H95P8K\" completed keep alive response.","severityLevel":"Verbose","properties":{"DeveloperMode":"true","ConnectionId":"0HL37O0H95P8K","AspNetCoreEnvironment":"Development","CategoryName":"Microsoft.AspNetCore.Server.Kestrel","{OriginalFormat}":"Connection id \"{ConnectionId}\" completed keep alive response."}}}}
Application Insights Telemetry (unconfigured): {"name":"Microsoft.ApplicationInsights.Dev.Message","time":"2017-03-10T14:18:01.3878990Z","tags":{"ai.cloud.roleInstance":"Desktop","ai.internal.sdkVersion":"aspnet5c:2.0.0","ai.location.ip":"::1","ai.operation.id":"0HL37O0HBESDM","ai.application.ver":"1.0.0.0","ai.internal.nodeName":"Desktop","ai.operation.name":"GET /api/test"},"data":{"baseType":"MessageData","baseData":{"ver":2,"message":"Request finished in 54.7982ms 404","severityLevel":"Information","properties":{"DeveloperMode":"true","ElapsedMilliseconds":"54.7982","AspNetCoreEnvironment":"Development","CategoryName":"Microsoft.AspNetCore.Hosting.Internal.WebHost","StatusCode":"404"}}}}
Microsoft.AspNetCore.Hosting.Internal.WebHost:Information: Request finished in 54.7982ms 404

Answer 1

This is not works, as mapping to action method is not defined. AFAIK, you may achieve the WebApi REST like routing ONLY using the attribute routing and you may define it on controller level:

[Route("api/[controller]")]
public class TestController : Controller
{
    [HttpGet]
    public long Get() => DateTimeOffset.Now.ToUnixTimeSeconds();
}

Update: have found this github issue Web API not working with convention based routin and:

for ASP.NET Core MVC we decided to adopt MVC 5.x's conventional routing approach and not Web API 2.x's approach. With the conventional routing approach, the route must specify both a controller and an action.

---

You may change route template to

template: "api/{controller}/{action}/{id?}"

But in this case, your URL will be /api/test/get.

---

Update 2 (based on the guide): you can include the NuGet package for Microsoft.AspNetCore.Mvc.WebApiCompatShim and still use ApiController. The code is on GitHub if you are curious as to what it does. Then you can define the WebApi routing:

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    app.UseMvc(routes =>
    {
        routes.MapWebApiRoute("DefaultApi", "api/{controller}/{id?}");
    });
}