ServiceCollection.Extensions.Modules

We all love to have modules to simplify registrations on our DI framework of choice.

Sadly Microsoft.Extensions.DependencyInjection doesn't have builtin modules.

Here is a naive, simple implementation that has been working for me.

How to use it

1. Inherit from ServiceCollection.Extensions.Modules.Module class

namespace MyFanceModulesTest
{
    using Microsoft.Extensions.DependencyInjection;
    using ServiceCollection.Extensions.Modules;

    public class MyFancyModule : Module
    {
        protected override void Load(IServiceCollection services)
        {
            base.Load(services);
            services.AddSingleton<TSERVICE, TSERVICEIMPL>();            
        }
    }
}

2. Register your module

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    public void ConfigureServices(IServiceCollection services)
    {
        services.RegisterModule<MyFancyModule>();
    }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        // More stuff here...
    }
}

• Boom! modules, modules, modules!!

Nested Modules

You can register modules inside modules....

namespace MyFancyNestedModulesTest
{
    using Microsoft.Extensions.DependencyInjection;
    using ServiceCollection.Extensions.Modules;

    public class InnerModule : Module
    {
        protected override void Load(IServiceCollection services)
        {
            base.Load(services); 
            // SOME FANCY REGISTRATIONS HERE
        }
    }

    public class OuterModule : Module
    {
        protected override void Load(IServiceCollection services)
        {
            base.Load(services);
            services.RegisterModule<InnerModule>();
            // MORE FANCY REGISTRATIONS HERE
         }
    }
}

Parameterized Modules

You can register instances of modules if you need some parameter....

namespace MyParameterizedModulesTest
{
    using Microsoft.Extensions.DependencyInjection;
    using ServiceCollection.Extensions.Modules;

    public class ParameterizedModule : Module
    {
        private readonly string _url;

        public ParameterizedModule(string url)
        {
        	_url = _url;
        }
		
        protected override void Load(IServiceCollection services)
        {
            base.Load(services); 
            // SOME FANCY REGISTRATIONS HERE using _url
        }
    }

    // and later on
    services.RegisterModule(new ParameterizedModule("https://google.com"));
}

Modules registration via Action

An action can be provided to register modules....

namespace MyParameterizedModulesTest
{
    using Microsoft.Extensions.DependencyInjection;
    using ServiceCollection.Extensions.Modules;

    public class ParameterizedModule : Module
    {
        private readonly string _url;

        public ParameterizedModule(string url)
        {
        	_url = _url;
        }
		
        protected override void Load(IServiceCollection services)
        {
            base.Load(services); 
            // SOME FANCY REGISTRATIONS HERE using _url
        }
    }

    // and later on
    services.RegisterModule(
		(collection) =>
	        {
		        var configuration = collection.BuildServiceProvider().GetRequiredService<IConfiguration>();
                return new ParameterizedModule(configuration["ApiUrl"]);
	        });
}

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