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.

You cannot register twice the same module in the same IServiceCollection, but you can register the same Module across different Collections.

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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