DependencyInjection.cs

using System.Reflection;
using MediatR;
using MediatR.Extensions.FluentValidation.AspNetCore;
using Microsoft.Extensions.DependencyInjection;

namespace SocialNetwork.Social.Application;

public static class DependencyInjection
{
    public static IServiceCollection AddApplicationServices(this IServiceCollection services)
    {
        services.AddAutoMapper(Assembly.GetExecutingAssembly());

        services.AddValidatorsFromAssembly(Assembly.GetExecutingAssembly());

        services.AddMediatR(cfg =>
        {
            cfg.RegisterServicesFromAssembly(Assembly.GetExecutingAssembly());
            cfg.AddBehavior(typeof(IPipelineBehavior<,>), typeof(ValidationBehavior<,>));
        });

        return services;
    }
}