I've got a MVC WebApi owin (soft hosted) project, that uses Unity for resolving controller dependencies
which look like this
public class PacientaiController : ODataController
{
private readonly IEntityRepo<Ent.Pacientas> repo;
public PacientaiController(IEntityRepo<Ent.Pacientas> repo)
{
this.repo = repo;
}
the problem I'm trying to solve - is how do I pass 'OwinContex' into a Repo.
public class PacientasEntityRepo:IEntityRepo<Pacientas>,IDisposable
{
public PacientasEntityRepo(IOwinContext ctx)
{
.........
If I try to register it like this in the Startup.cs
Container.RegisterType<IOwinContext>(new InjectionFactory(o => HttpContext.Current.GetOwinContext()));
I get a null ref, saying that HttpContext.Current
is NULL
The main idea here, is to pass the currently authenticated user to the repo, because Repo host the Logic for querying the Database, depending on the user. (say if the user is Admin, then return this data, if the user is guest - return this data)
The point being - that this is a self Host !
Lets put aside why you have this design and concentrate to the problem: injecting the IOwinContext
:
you can also get it from a HttpRequestMessage
instance with the GetOwinContext
method, however you also need to get a HttpRequestMessage
somehow.
Unity does not support injection of the HttpRequestMessage
out of the box but you can use a custom DelegatingHandler
which stores the current HttpRequestMessage
in the container as described here: Inject WebAPI UrlHelper into service using Autofac
The linked question is about Autofac but you can transfer it for work with Unity:
The CurrentRequest
and the CurrentRequestHandler
can be used from Andrew Davey's answer as it is:
public class CurrentRequest
{
public HttpRequestMessage Value { get; set; }
}
public class CurrentRequestHandler : DelegatingHandler
{
protected async override System.Threading.Tasks.Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
{
var scope = request.GetDependencyScope();
var currentRequest = (CurrentRequest)scope.GetService(typeof(CurrentRequest));
currentRequest.Value = request;
return await base.SendAsync(request, cancellationToken);
}
}
Then you just need to register the DelegatingHandler
with:
httpConfiguration.MessageHandlers.Insert(0, new CurrentRequestHandler());
And register the CurrentRequest
and IOwinContext
in the container
container.RegisterType<CurrentRequest>(
new HierarchicalLifetimeManager());
container.RegisterType<IOwinContext>(
new HierarchicalLifetimeManager(),
new InjectionFactory(c => c.Resolve<CurrentRequest>().Value.GetOwinContext()));
httpConfiguration.DependencyResolver = new UnityHierarchicalDependencyResolver(container);
Beside the custom delegation handler there are other places to hook into Web.API to capture the HttpRequestMessage
for example you can create your own IHttpControllerActivator
and use the ExecuteAsync
method as described here: Dependency Injection in ASP.NET Web API 2