在自托管的WebApi项目中看不到我的控制器

Question

I created a self hosted web api app, to run as a Windows Service, using TopShelf, and Autofac for dependency injection.

Here is my StartUp logic:

public class ApiShell : IApiShell
{
    public void Start()
    {
        using (WebApp.Start<Startup>("http://localhost:9090"))
        {
            Console.WriteLine($"Web server running at 'http://localhost:9090'");
        }
    }

    internal class Startup
    {
        //Configure Web API for Self-Host
        public void Configuration(IAppBuilder app)
        {
            var config = new HttpConfiguration();

            GlobalConfiguration.Configuration
              .EnableSwagger(c => c.SingleApiVersion("v1", "Swagger UI"))
              .EnableSwaggerUi();

            //default route
            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional });

            app.UseWebApi(config);
        }
    }
}

And I start the WebApp as follow:

public class HostService
{
    //when windows service statrts
    public void Start()
    {
        IoC.Container.Resolve<IApiShell>().Start();  //start web app
        IoC.Container.Resolve<IActorSystemShell>().Start();
    }

    //when windows service stops
    public void Stop()
    {
        IoC.Container.Resolve<IActorSystemShell>().Stop();
    }
}

TopShelf configuration:

HostFactory.Run(x =>
        {
            x.Service<HostService>(s =>
            {
                s.ConstructUsing(name => new HostService());
                s.WhenStarted(sn => sn.Start());
                s.WhenStopped(sn => sn.Stop());
            });
            x.RunAsLocalSystem();
            x.SetDescription("Sample Service");
            x.SetDisplayName("Sample Service");
            x.SetServiceName("Sample Service");
        });

My controller:

public class PingController : ApiController
{
    private IActorSystemShell _actorSystem;

    public PingController(IActorSystemShell actorSystem)
    {
        _actorSystem = actorSystem;
    }

    [HttpGet]
    public async Task<string> Ping()
    {
        var response = await _actorSystem.PingActor.Ask<PingMessages.Pong>(PingMessages.Ping.Instance(), 
            TimeSpan.FromSeconds(10));

        return response.PongMessage;
    }
}

I installed Swagger as well, but I can't reach my controller, using either of the following attempts:

http://localhost:9090/api/Ping

http://localhost:9090/swagger

What am I missing?

Answer 1

You can't just do this:

using (WebApp.Start<Startup>("http://localhost:9090"))
{
    Console.WriteLine($"Web server running at 'http://localhost:9090'");
}

After the write line, there's no more statements left in the using, so the using will close, thus stopping the web app. This is one of those cases where even though the result of WebApp.Start is an IDisposable , you shouldn't use a using statement. Instead, do this:

public class ApiShell : IApiShell
{
    _IDisposable _webApp;

    public void Start()
    {
        _webApp = WebApp.Start<Startup>("http://localhost:9090");
        Console.WriteLine($"Web server running at 'http://localhost:9090'");
    }

    public void Stop()
    {
        _webApp.Dispose();
    }
}

public class HostService
{
    public void Start()
    {
        IoC.Container.Resolve<IApiShell>().Start();  //start web app
    }

    public void Stop()
    {
        IoC.Container.Resolve<IApiShell>().Stop();  //stop web app
    }
}

You haven't shown your dependency registration, but make sure that IApiShell is registered as a singleton so you're starting/stopping the same instance.

Note, if this were a traditional console app instead of a Windows service, you could do this:

using (WebApp.Start<Startup>("http://localhost:9090"))
{
    Console.WriteLine($"Web server running at 'http://localhost:9090'");
    Console.WriteLine("Press any key to exit.");
    Console.ReadKey(true);
}

The ReadKey method would keep the using statement active and thus keep the web app from disposing.