1234567891011121314

using MediatR;

public class UserRegisteredNotification : INotification
{
    public string UserId { get; }
    public string Email { get; }

    public UserRegisteredNotification(string userId, string email)
    {
        UserId = userId;
        Email = email;
    }
}

1234567891011121314151617

public class SendWelcomeEmailHandler : INotificationHandler<UserRegisteredNotification>
{
    private readonly ILogger<SendWelcomeEmailHandler> _logger;

    public SendWelcomeEmailHandler(ILogger<SendWelcomeEmailHandler> logger)
    {
        _logger = logger;
    }

    public Task Handle(UserRegisteredNotification notification, CancellationToken cancellationToken)
    {
        _logger.LogInformation($"Sending welcome email to {notification.Email}");
        // Simulate sending email logic
        return Task.CompletedTask;
    }
}

12345678910111213141516

public class LogUserRegistrationHandler : INotificationHandler<UserRegisteredNotification>
{
    private readonly ILogger<LogUserRegistrationHandler> _logger;

    public LogUserRegistrationHandler(ILogger<LogUserRegistrationHandler> logger)
    {
        _logger = logger;
    }

    public Task Handle(UserRegisteredNotification notification, CancellationToken cancellationToken)
    {
        _logger.LogInformation($"User registered: {notification.UserId}, Email: {notification.Email}");
        return Task.CompletedTask;
    }
}

12345678910111213141516

public class AnalyticsServiceHandler : INotificationHandler<UserRegisteredNotification>
{
    private readonly ILogger<AnalyticsServiceHandler> _logger;

    public AnalyticsServiceHandler(ILogger<AnalyticsServiceHandler> logger)
    {
        _logger = logger;
    }

    public Task Handle(UserRegisteredNotification notification, CancellationToken cancellationToken)
    {
        _logger.LogInformation($"Analytics: Tracking new user registration for {notification.UserId}");
        return Task.CompletedTask;
    }
}

1234567891011121314151617181920212223

var builder = WebApplication.CreateBuilder(args);

// Register MediatR
builder.Services.AddMediatR(Assembly.GetExecutingAssembly());

var app = builder.Build();

// Minimal API Endpoint for User Registration
app.MapPost("/register", async (UserRegistrationRequest request, IMediator mediator) =>
{
    var userId = Guid.NewGuid().ToString();

    // Simulating user registration (e.g., saving to database)
    await mediator.Publish(new UserRegisteredNotification(userId, request.Email));

    return Results.Ok(new { Message = "User registered successfully!", UserId = userId });
});

app.Run();

// DTO for user registration
public record UserRegistrationRequest(string Email);