How do IServiceClient interfers the type?

1

Hello,
I’m using the repository pattern to make call from my WPF application to a webservice using IServiceClient… My repositories inherits from a base class and all the methods are in the form

 public Task<IList<Institute>> GetInstitutesAsync()
    {
        var client = GetServiceStackClient();

        var request = new InstituteRequest();

        return client.PostAsync(request);
    }

    public Task<IList<Status>> GetStatusAsync()
    {
        var client = GetServiceStackClient();

        var request = new StatusRequest();

        return client.PostAsync(request);
    }

I’ve created a generic method that wraps the Servicestack creation and the PostAsync so I can call the methods in the form

public Task<IList<Portfolio>> GetPortfoliosAsync(string username)
    {
        var request = new PortfolioRequest
        {
            UserName = username
        };

         return Get<IList<Portfolio>, PortfolioRequest>(request);
    }

And the generic method is defined inside a DefaultRepositoryBase as

  public class DefaultRepositoryBase : RepositoryBase
{
    private static IServiceClient GetServiceStackClient(string path = "")
    {
        var defaultServerSettings = ServiceLocator.Default.ResolveType<ITesoreriaServerSettings>();
        return defaultServerSettings.GetServiceStackClient(path);
    }

    internal static Task<TResponse> Get<TResponse, TRequest>(TRequest request)
        
    {
        var client = GetServiceStackClient();
        return client.PostAsync<TResponse>(request);
    }
}

I was wondering how the PostAsync can infers the types while I can’t (so I’ve to write the <TResponse,TRequest>

Is there a way I can avoid to write them?

Thanks
Paolo

2

Firstly please don’t use interfaces like IList in DTOs they have zero value and can cause runtime issues, use a concrete List instead.

If you’re asking why you need to specify the Response Type on the call site, it’s because you need the IReturn Interface marker on Request DTOs.

3

I’m migrating my code to use List, it’s a quite huge work !
I mean Servicestack is so wounderfull, I’ve got this DTO

  public class AccountUnwrappedRequest : IReturn<List<AccountUnwrapped>>
{
}

it’s used here

    public Task<IList<AccountUnwrapped>> GetAccountsUnwrapped()
    {
        var client = GetServiceStackClient();

        var request = new AccountUnwrappedRequest();

        return client.PostAsync(request);
    }

And in the PostAsync I don’t have to specify the return type, since it’s inferred I think from the Request

How can I have the same behavior here

 public Task<List<Portfolio>> GetPortfoliosAsync(string username)
    {
        var request = new PortfolioRequest
        {
            UserName = username
        };

        return Get<List<Portfolio>, PortfolioRequest>(request);
    }

to be able to do

  return Get(request);

Is it possible? How?

4

This is how C# generics works, either all generic types need to be inferred or you need to specify all of them on the call-site.

If you want them inferred your Get should look like IRestClient’s Get method:

TResponse Get<TResponse>(IReturn<TResponse> requestDto);

Where it accepts a Typed Request DTO with the IReturn<T> interface marker which holds the generic Type of the Response which is how it can be inferred.

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