Using Unity instead of ASP.Net Core DI IServiceCollection

Question

More and more .NET Core libraries is bound to IServiceCollection. In example, I want to use HttpClientFactory described here in my NET Framework 4.7.1. desktop application. My application is using Unity IoC. I referenced Microsoft.Extensions.Http as NuGet.

But there is a problem: new ASP.Net Core components are bound to Microsoft DI framework for .NetCore - IServiceCollection. In example, registration of HttpClientFactory is here:

public void ConfigureServices(IServiceCollection services)
{
    services.AddHttpClient();
}

I was going deeper into MS code and wanted to manually register corresponding interfaces and classes to Unity. This is how services are registered by IServiceCollection:

services.TryAddTransient<HttpMessageHandlerBuilder, DefaultHttpMessageHandlerBuilder>();
services.TryAddSingleton<IHttpClientFactory, DefaultHttpClientFactory>();

This would be no problem to move this to Unity IoC, but I am stucked when I want to register DefaultHttpMessageHandlerBuilder and DefaultHttpClientFactory which have internal visibility. So they are not available for registration outside of MS code.

Do I have any chance how to resolve this situation?

Causeway

Well, as you said, the two concrete types you are looking to use are internal, so that's that, you can't directly use them. Just wanted to add a thought: can you set up your Unity IOC so that it resolves IHttpClientFactory by in turn resolving IHttpClientFactory from the ASP.NET IServiceCollection? – Taliped

I resolved this issue by using unity adapter for IServiceCollection: https://mcmap.net/q/1132300/-using-unity-instead-of-asp-net-core-di-iservicecollection – Causeway

Answer 1

Edit 7.12.2022: Unity is now deprecated, so do not use it for new projects. I replaced it with Autofac.

Based on @davidfowl answer, I have used his second solution and completed code:

These packages need to be referenced from my project (snippet from .csproj):

 <ItemGroup>
    <PackageReference Include="Microsoft.Extensions.Http">
      <Version>2.1.1</Version>
    </PackageReference>
    <PackageReference Include="Unity.Microsoft.DependencyInjection">
      <Version>2.0.10</Version>
    </PackageReference>
  </ItemGroup>

And here is the test that services from ServiceCollection can be resolved from Unity container:

using System;
using System.Linq;
using System.Net.Http;
using Microsoft.Extensions.DependencyInjection;
using Unity;
using Unity.Microsoft.DependencyInjection;
using Xunit;

namespace FunctionalTests
{
    public class UnityWithHttpClientFactoryTest
    {

        /// <summary>
        /// Integration of Unity container with MS ServiceCollection test
        /// </summary>
        [Fact]
        public void HttpClientCanBeCreatedByUnity()
        {
            UnityContainer unityContainer = new UnityContainer();

            ServiceCollection serviceCollection = new ServiceCollection();
            serviceCollection.AddHttpClient("Google", (c) =>
            {
                c.BaseAddress = new Uri("https://google.com/");
            });
            serviceCollection.BuildServiceProvider(unityContainer);

            Assert.True(unityContainer.IsRegistered<IHttpClientFactory>());
            IHttpClientFactory clientFactory = unityContainer.Resolve<IHttpClientFactory>();
            HttpClient httpClient = clientFactory.CreateClient("Google");

            Assert.NotNull(httpClient);
            Assert.Equal("https://google.com/", httpClient.BaseAddress.ToString());

        }

    }
}

Causeway

Note: in case of a very minimal .csproj, the full DependencyInjection dependency might be missing. I had to add it with <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="2.2.0" />. – Hanhhank

This doesn't work for me. ServiceCollection seems to come from Microsoft.Extensions.DependencyInjection, but I do not see a using in your example for this. It isn't found in Unity's package. Also there's no AddHttpClient() method, so I'm not sure where that's coming from. – Presber

@Presber Everything that you are missing is in usings directive. Check if you have appropriate NuGet packages (their version will be higher now). – Causeway

Answer 2

You have 2 options:

• Create a ServiceCollection, add the factory and then call BuildServiceProvider and resolve the IHttpClientFactory. There's an uber sample here https://github.com/aspnet/HttpClientFactory/blob/64ed5889635b07b61923ed5fd9c8b69c997deac0/samples/HttpClientFactorySample/Program.cs#L21.

• Use the unity adapter for IServiceCollection https://www.nuget.org/packages/Unity.Microsoft.DependencyInjection/.

Aranda