Generic Interface on Application Layer

[igorgomeslima]

Hi folks!

I want to implement an generic Interface<T> in Application Layer, but by design we can not add reference to Infrastructure Layer (where the concrete implementation resides) on Application Layer, on this way I can't inject generic Interface<T> services on my Commands Handlers.

Any tips or another mindset about it? 😎

Some code:

namespace Application.Common.Interfaces

public interface IJobOne<T>
{
    bool DoJob(...);
}

namespace Infrastructure.Services

public class PartnerAJobOne : IJobOne<PartnerAJobOne>
{
      private readonly HttpClient _httpClient;

      public PartnerAJobOne(HttpClient client)
      {
          _httpClient = client;
      }

      public bool DoJob(...)
      {
           // _httpClient.MakeHttpRequest...
      }
}

public class PartnerBJobOne : IJobOne<PartnerBJobOne>
{
        private readonly HttpClient _httpClient;

        public PartnerAJobOne(HttpClient client)
        {
            _httpClient = client;
        }

        public bool DoJob(...)
        {
            // _httpClient.MakeHttpRequest...
        }
}

namespace Application.JobOne.Commands

public class JobOneCommandHandler : IRequestHandler<JobOneCommand, bool>
{
    private readonly IJobOne<PartnerAJobOne> _jobOnePartnerA;
    private readonly IJobOne<PartnerBJobOne> _jobOnePartnerB;

    //... We can't inject it on `JobOneCommandHandler` constructor for example...
    //... PartnerAJobOne.cs belongs on `Infrastructure Layer`
    //... PartnerBJobOne.cs belongs on `Infrastructure Layer`

    public JobOneCommandHandler(IJobOne<PartnerAJobOne> jobOnePartnerA, IJobOne<PartnerBJobOne> jobOnePartnerB)
    {
        _jobOnePartnerA = jobOnePartnerA;
        _jobOnePartnerB = jobOnePartnerB;
    }

    public Task<bool> Handle(JobOneCommand request, CancellationToken cancellationToken)
    {
        if(...)
	  _jobOnePartnerA.DoJob(...)
	else
	  _jobOnePartnerB.DoJob(...)
    }
}

D.I

services.AddTransient<IJobOne<PartnerAJobOne>, PartnerAJobOne>();
services.AddTransient<IJobOne<PartnerBJobOne>, PartnerBJobOne>();

-

services.AddHttpClient<IJobOne<PartnerAJobOne>, PartnerAJobOne>("parterA", configureClient =>
{
      configureClient.BaseAddress = new Uri("http://");
});

services.AddHttpClient<IJobOne<PartnerBJobOne>, PartnerBJobOne>("parterB", configureClient =>
{
      configureClient.BaseAddress = new Uri("http://");
});

Cheers!

[karimkod]

What's the purpose of PartnerAJobOne.cs and PartnerBJobOne.cs ? and Why are they defined in Infrastructure ?

[igorgomeslima]

Well, they make IO access to external world over HTTP protocol. I've just put this information on discussion.

[karimkod]

Yes, and why do you need to define them as generics, I don't know this feels like an x y problem.

[igorgomeslima]

@karimkod Since you called me on Discord, please, let's continue on channel: Message. I've put more info here later, after discussion.