Cannot resolve with IServerSideEvents dependancy

Question

Extening on : IOC injection of IServerSideEvents

I am trying to setup a Singleton on the container which requires IServerSideEvents (IMessager has the dependancy).

 // setup Engine
List<IFileHandler> handler = new List<IFileHandler>() { new FileHandler() };
var engine = new Engine(handler, new List<IFileConverter>());
engine.Fail += container.Resolve<IMessager>().Error;
container.AddSingleton<Engine>(engine);

This is becuase I need to bind same events in multiple controllers but the events are in an external library. I can bind them fine on injection of a controller, but trying to get IOC to handle it will not work, returns the same error as above.

I imagine this is a loading order issue and when I am attempting to resolve the dependancy, the plugins have yet to be loaded. This is being attemtped in the Configure(Container container) method

Answer 1

Please read section on the .NET Core Container Adapter:

any dependencies registered .NET Core Startup are also available to ServiceStack but dependencies registered in ServiceStack’s IOC are only visible to ServiceStack.

So if you need dependencies available to both ServiceStack and external ASP.NET Core features like MVC you need to register them in your Startup.ConfigureServices().

Plugins

From your link:

public override void Configure(Funq.Container container)
{
    var serverEventsFeature = new ServerEventsFeature();
    // bind server events
    serverEventsFeature.Register(this);         
    container.AddSingleton(new Engine(container.Resolve<IServerEvents>()));
}

Plugins should never be called directly like this, they're expected to be registered in the Plugins collection:

Plugins.Add(new ServerEventsFeature());

Plugins are registered after Configure() is run, if you want to register a dependency that uses IServerEvents registered by the ServerEventsFeature you would need to either register your dependency with a factory function, i.e:

container.AddSingleton<ICacheClient>(c => 
    new Engine(c.Resolve<IServerEvents>()));

Alternatively you can register a singleton instance an AfterInitCallbacks which is run at the end of AppHost initialization, e.g:

AfterInitCallbacks.Add(host => {
    container.AddSingleton<ICacheClient>(
        new Engine(c.Resolve<IServerEvents>()));
});

If you wanted to register a singleton that any other Plugin registered you can have your plugin to implement IPostInitPlugin which runs AfterPluginsLoaded() after all plugins are registered:

public class MyPlugin : IPlugin, IPostInitPlugin
{
    public void Register(IAppHost appHost) {}

    public void AfterPluginsLoaded(IAppHost appHost)
    {
        appHost.GetContainer().AddSingleton<ICacheClient>(c => 
            new Engine(c.Resolve<IServerEvents>()));
    }
}