I'm finding my feet with Web Api 2, Owin and Autofac and need some guidance, please.
Overview
I have an Owin self-hosted Web Api that uses Autofac for IoC and dependency injection. The project is a console app acting like a service, meaning it can be stopped and started. I have an Authentication controller with two constructors: one parameter-less and the other injects a repository.
Problem
When I run the service and call the api, my parameter-less constructor is called and my repository never gets injected (_repository = null).
Research
I've done a fair bit of research and found some helpful projects on Github, which I replicated to the tee but I'm missing a big part of the puzzle. This was helpful but didn't solve my problem. I read this question on Stack Overflow and Dane Sparza had a nice demo project but I couldn't find a clear solution. The problem is not the self-hosting but the dependency injection.
My code (thinned out for explanation)
public class Startup
{
public void Configuration(IAppBuilder app)
{
HttpConfiguration config = new HttpConfiguration();
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
var json = config.Formatters.JsonFormatter;
json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects;
config.Formatters.Remove(config.Formatters.XmlFormatter);
var connectioninfo = ConnectionInfo.FromAppConfig("mongodb");
var builder = new ContainerBuilder(); // Create the container builder.
builder.RegisterApiControllers(Assembly.GetExecutingAssembly()); // Register the Web API controllers.
builder.Register(c => new Logger()).As<ILogger>().InstancePerRequest(); // Register a logger service to be used by the controller and middleware.
builder.RegisterType<AuthenticationRepository>().As<IAuthenticationRepository>().WithParameter(new NamedParameter("connectionInfo", connectioninfo)).InstancePerRequest();
var container = builder.Build();
var resolver = new AutofacWebApiDependencyResolver(container); // Create an assign a dependency resolver for Web API to use.
GlobalConfiguration.Configuration.DependencyResolver = resolver; // Configure Web API with the dependency resolver
app.UseCors(CorsOptions.AllowAll);
app.UseWebApi(config);
app.UseAutofacWebApi(config); // Make sure the Autofac lifetime scope is passed to Web API.
}
Program.cs
static void Main(string[] args)
{
var service = new ApiService(typeof(Program), args);
var baseAddress = "http://localhost:9000/";
IDisposable _server = null;
service.Run(
delegate()
{
_server = WebApp.Start<Startup>(url: baseAddress);
},
delegate()
{
if (_server != null)
{
_server.Dispose();
}
}
);
}
ApiController
public class AuthenticationController : ApiController
{
private IAuthenticationRepository _repository;
public AuthenticationController() { }
public AuthenticationController(IAuthenticationRepository repository)
{
_repository = repository;
}
[AllowAnonymous]
public IHttpActionResult Authenticate(string name, string password)
{
if (_repository == null)
return BadRequest("User repository is null.");
var valid = _repository.AuthenticateUser(name, password);
return Ok(valid);
}
}
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