FluentDI 1.0.0

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What is FluentDI

FluentDI is an utility library that allows for Dependency Injection through Attributes, making code cleaner and easier to find whether a service is being injected or not.

How does it work?

First of all, after installing the package, FluentDI must be enabled during app building.

using FluentDI;

WebApplication Application;

var builder = WebApplication.CreateBuilder(args);

//Add fluent Dependency Injection
builder.AddFluentDI();

builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

FluentDI is compatible with regular Dependency Injection

Once enabled, in order to load the services, the Attribute Injector must be added to the desired services

    [Injector<ITimeOfDayService>]
    public class EveningOfDay : ITimeOfDayService
    {}

If no value is provided, default lifetime is Scoped, this can be modified

    [Injector<IStatusService>(ServiceLifetime.Singleton)]
    public class StatusService : IStatusService
    {}
    ---
    [Injector<TimeService>(ServiceLifetime.Transient)]
    public class TimeService
    {}

Pretty simple right? 😃

Conditional Injection

Additionally, this library allows for injection of multiple implementations of a same interface, and decide which one to load based on a condition, supplied by a class implementation

    public class TimeOfDaySelector : IRuntimeDependencySelector<ITimeOfDayService>
    {
        public Func<ITimeOfDayService, object[], bool> CanInject => (s, param) =>
        {
            if (param.Length == 0 || param[0] is not DateTime date)
                throw new ArgumentException("Param must be a date");

            var time = TimeOnly.FromDateTime(date);
            
            return time >= s.From && time <= s.To;
        };
    }

Then add the Injector attribute to all implementations

    [Injector<ITimeOfDayService>]
    public class MorningOfDayService : ITimeOfDayService
    {
        public TimeOnly From => new TimeOnly(8, 0, 0);

        public TimeOnly To => new TimeOnly(12, 0, 0);

        public string GetTimeOfDay()
        {
            return "It's daytime!";
        }
    }

    [Injector<ITimeOfDayService>]
    public class NightOfDay : ITimeOfDayService
    {
        public TimeOnly From => new TimeOnly(18, 0, 0);

        public TimeOnly To => new TimeOnly(23, 59, 0);

        public string GetTimeOfDay()
        {
            return "It's nighttime!";
        }
    }

Lastly, when requesting for the service, it must be done through DependencyFactory<> class

        public TimeOfDayController(IDependencyFactory<ITimeOfDayService> dependencyFactory)
        {
            this.TimeOfDayService = dependencyFactory.Get(DateTime.Now);
        }