Implementing generic dependency injection configuration for consistent and scalable service registration.

SampleWebApiAspNetCore/Common/DependencyInjectionConfig.cs

@@ -0,0 +1,38 @@
+using SampleWebApiAspNetCore.Common.Interface;
+
+namespace SampleWebApiAspNetCore.Common;
+
+internal static class DependencyInjectionConfig
+{
+    internal static IServiceCollection AddContracts(this IServiceCollection services)
+    {
+        services.RegisterImplementations(typeof(ITransientService), ServiceLifetime.Transient);
+        services.RegisterImplementations(typeof(IScopedService), ServiceLifetime.Scoped);
+        services.RegisterImplementations(typeof(ISingletonService), ServiceLifetime.Singleton);
+        return services;
+    }
+    private static IServiceCollection RegisterImplementations(this IServiceCollection services, Type interfaceType, ServiceLifetime lifetime)
+    {
+        var implementationTypes = AppDomain.CurrentDomain.GetAssemblies()
+            .SelectMany(assembly => assembly.GetTypes())
+            .Where(type => interfaceType.IsAssignableFrom(type) && type.IsClass && !type.IsAbstract)
+            .Select(type => new { Interface = type.GetInterfaces().FirstOrDefault(), Implementation = type })
+            .Where(type => type.Interface != null && interfaceType.IsAssignableFrom(type.Interface));
+
+        foreach (var implementationType in implementationTypes)
+            services.RegisterService(implementationType.Interface!, implementationType.Implementation, lifetime);
+
+        return services;
+    }
+
+    private static IServiceCollection RegisterService(this IServiceCollection services, Type interfaceType, Type implementationType, ServiceLifetime lifetime)
+    {
+        return lifetime switch
+        {
+            ServiceLifetime.Transient => services.AddTransient(interfaceType, implementationType),
+            ServiceLifetime.Scoped => services.AddScoped(interfaceType, implementationType),
+            ServiceLifetime.Singleton => services.AddSingleton(interfaceType, implementationType),
+            _ => throw new ArgumentException("Invalid lifetime specified", nameof(lifetime))
+        };
+    }
+}

SampleWebApiAspNetCore/Common/Interface/IScopedService.cs

@@ -0,0 +1,12 @@
+namespace SampleWebApiAspNetCore.Common.Interface;
+
+/// <summary>
+/// Interface for a scoped service in dependency injection.
+/// Scoped services are created once per request.
+/// 
+/// If an interface inherits this interface, it will be automatically registered
+/// by a common dependency injection configuration class.
+/// </summary>
+public interface IScopedService
+{
+}

SampleWebApiAspNetCore/Common/Interface/ISingletonService.cs

@@ -0,0 +1,12 @@
+namespace SampleWebApiAspNetCore.Common.Interface;
+
+/// <summary>
+/// Interface for a singleton service in dependency injection.
+/// Singleton services are created once and shared throughout the application.
+/// 
+/// If an interface inherits this interface, it will be automatically registered
+/// by a common dependency injection configuration class.
+/// </summary>
+public interface ISingletonService
+{
+}

SampleWebApiAspNetCore/Common/Interface/ITransientService.cs

@@ -0,0 +1,13 @@
+namespace SampleWebApiAspNetCore.Common.Interface;
+
+/// <summary>
+/// Interface for a transient service in dependency injection.
+/// Transient services are created anew each time they are requested.
+/// 
+/// If an interface inherits this interface, it will be automatically registered
+/// by a common dependency injection configuration class.
+/// </summary>
+public interface ITransientService
+{
+}
+

SampleWebApiAspNetCore/Program.cs

@@ -1,11 +1,11 @@
-using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.ApiExplorer;
 using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.AspNetCore.Mvc.Routing;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Options;
 using Newtonsoft.Json.Serialization;
 using SampleWebApiAspNetCore;
+using SampleWebApiAspNetCore.Common;
 using SampleWebApiAspNetCore.Helpers;
 using SampleWebApiAspNetCore.MappingProfiles;
 using SampleWebApiAspNetCore.Repositories;
@@ -18,16 +18,18 @@
 
 builder.Services.AddControllers()
                 .AddNewtonsoftJson(options =>
-                       options.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver()); 
+                       options.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver());
 
 // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
 builder.Services.AddEndpointsApiExplorer();
 builder.Services.AddSwaggerGen();
 
 builder.Services.AddCustomCors("AllowAllOrigins");
 
-builder.Services.AddSingleton<ISeedDataService, SeedDataService>();
-builder.Services.AddScoped<IFoodRepository, FoodSqlRepository>();
+//All services of the application will be configured and registered using a generic approach by AddContracts.
+builder.Services.AddContracts();
+//builder.Services.AddSingleton<ISeedDataService, SeedDataService>();
+//builder.Services.AddScoped<IFoodRepository, FoodSqlRepository>();
 builder.Services.AddScoped(typeof(ILinkService<>), typeof(LinkService<>));
 builder.Services.AddTransient<IConfigureOptions<SwaggerGenOptions>, ConfigureSwaggerOptions>();
 
@@ -63,7 +65,7 @@
         });
 
     app.SeedData();
-} 
+}
 else
 {
     app.AddProductionExceptionHandling(loggerFactory);

SampleWebApiAspNetCore/Repositories/IFoodRepository.cs

@@ -1,9 +1,10 @@
-using SampleWebApiAspNetCore.Entities;
+using SampleWebApiAspNetCore.Common.Interface;
+using SampleWebApiAspNetCore.Entities;
 using SampleWebApiAspNetCore.Models;
 
 namespace SampleWebApiAspNetCore.Repositories
 {
-    public interface IFoodRepository
+    public interface IFoodRepository : IScopedService
     {
         FoodEntity GetSingle(int id);
         void Add(FoodEntity item);

SampleWebApiAspNetCore/Services/ISeedDataService.cs

@@ -1,8 +1,9 @@
-using SampleWebApiAspNetCore.Repositories;
+using SampleWebApiAspNetCore.Common.Interface;
+using SampleWebApiAspNetCore.Repositories;
 
 namespace SampleWebApiAspNetCore.Services
 {
-    public interface ISeedDataService
+    public interface ISeedDataService : ISingletonService
     {
         void Initialize(FoodDbContext context);
     }