CODEWITHSUNDEEP
asp.net-mvcasp.net-web-apiunity-container
Ankit K
Ankit K

Reputation: 1326

Using unity DI in both web api and class library

I am creating a new web api project. In this i am using two more class library projects apart from web api project Like this:

MyBlog.API (Web API project)
MyBlog.Services (Class library)- Contains additional business logic
MyBlog.Repositories (Class library) - contains all database related operations

In API project i have added the reference of Services project and in Services project i have added reference of Repositories project so API will call services and services will call repositories as this:

API > Services > Repositories

I don't want to call repositories directly form my api controllers they will be called through services. So i am not adding repository project reference in api project.

Now i am implementing unity.webapi dependency injection in my api project. Following is the code for implementing DI:

Repositories code:

namespace MyBlogs.Repositories
{
    public interface ITestRepository
    {
        string Get();
    }
}

namespace MyBlogs.Repositories
{
    public class TestRepository:ITestRepository
    {
        public string Get()
        {
            return "test";
        }
    }
}

Services code with DI implementation:

namespace MyBlogs.Services
{
    public interface ITestService
    {
        string Get();
    }
}

namespace MyBlogs.Services
{
    public class TestService : ITestService
    {
        private ITestRepository testRepository;

        public TestService(ITestRepository testRepositoryParam)
        {
            this.testRepository = testRepositoryParam;
        }

        public string Get()
        {
            return this.testRepository.Get();
        }
    }
}

Controller code:

public class ValuesController : ApiController
    {
        private ITestService testService;
        public ValuesController(ITestService testServiceParam)
        {
            this.testService = testServiceParam;
        }

        // GET api/values
        public IEnumerable<string> Get()
        {
            return new string[] { this.testService.Get() };
        }
}

and finally unityconfig file:

public static class UnityConfig
    {
        public static void RegisterComponents()
        {
            var container = new UnityContainer();
            container.RegisterType<ITestService, TestService>();

            GlobalConfiguration.Configuration.DependencyResolver = new UnityDependencyResolver(container);
        }
    }

Now i am facing the issue here, as i have not added repository project reference in api project where i have this unityconfig file so how can i register ITestRepository and TestRepository in unity similart to ITestService and TestService?? Is there any way i could register my repository project's dependencies somewhere else without adding the project reference?? or if i will try to add unity in services project then how will it gets registered??

I have registered unityConfig in global.asax of web api project:

protected void Application_Start()
        {
            UnityConfig.RegisterComponents();
        }

Upvotes: 2

Views: 1275

Answers (2)

Ankit K
Ankit K

Reputation: 1326

I solved it by creating a unity file in service project and called its RegisterComponents method directly from unity file of api project by passing same UnityContainer as a parameter to service's unity file like this:

public static class UnityConfig
{
    public static void RegisterComponents()
    {
    var container = new UnityContainer();

        container.RegisterType<ITestService, TestService>();
        ServiceUnityConfig.RegisterComponents(container);

        GlobalConfiguration.Configuration.DependencyResolver = new UnityDependencyResolver(container);
    }
}

public static class ServiceUnityConfig
{
    public static void RegisterComponents(UnityContainer container)
    {
        container.RegisterType<ITestRepository, TestRepository>();
    }
}

It solved my problem without registering unity two times in app_start. Thanks for above answer of eran, based on above answer i implemented it like this.

Upvotes: 1

eran otzap
eran otzap

Reputation: 12533

That's a good question and i haven't done this myself with unity. Autofac, Windsor and other DI's let you expose modules or installers from each assembly and then you load modules from other assemblies that do reference them.

so i'm just going to propose a general solution based on that idea. (Hope this can work :) ) 

public static class WebApiUnityConfig
{
    public static void RegisterComponents()
    {
        var container = new UnityContainer();
        container.RegisterType<ITestService, TestService>();

        GlobalConfiguration.Configuration.DependencyResolver = new UnityDependencyResolver(container);
    }
}   


public static class ServicesUnityConfig
{
    public static void RegisterComponents()
    {
        var container = new UnityContainer();
        container.RegisterType<ITestRepository, TestRepository>();

        GlobalConfiguration.Configuration.DependencyResolver = new UnityDependencyResolver(container);
    }
}   


protected void Application_Start()
{
     ServiceUnityConfig.RegisterComponents();
     WebApiUnityConfig.RegisterComponents();
}

Upvotes: 2

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