Decode.Notifications 3.0.0

Decode.Notifications

A simple and lightweight library for domain notifications using the notification pattern in .NET.

📦 Installation

dotnet add package Decode.Notifications

🛠️ Usage

1. Dependency Injection Configuration

In your Program.cs or Startup.cs:

using Decode.Notifications.Extensions;

// You can use AddDomainNotifications() or the alias AddDecodeNotifications()
builder.Services.AddDomainNotifications();

2. Using in Services or Domain Logic

public class UserService
{
    private readonly IDomainNotificationContext _notificationContext;

    public UserService(IDomainNotificationContext notificationContext)
    {
        _notificationContext = notificationContext;
    }

    public void RegisterUser(string username)
    {
        if (string.IsNullOrWhiteSpace(username))
        {
            _notificationContext.Add("Username is required.", HttpStatusCode.BadRequest, nameof(username));
            return;
        }

        // Logic...
    }
}

3. The DomainNotification Model & Context Operations

Under the hood, notifications are stored as DomainNotification objects in the context.

DomainNotification Class Structure

• Message (string): The validation or error message.
• StatusCode (int): The HTTP status code representation (defaults to 400).
• Key (string?): Optional parameter representing the field name or key (e.g. nameof(username)).

Additional Context Methods

You can also add individual notifications directly or batch multiple notifications:

// Add an explicit DomainNotification object
_notificationContext.Add(new DomainNotification("Email is invalid", 422, "Email"));

// Add a collection of DomainNotifications at once (useful for batch validations)
List<DomainNotification> notificationBatch =
[
    new DomainNotification("Password is too short", 400, "Password"),
    new DomainNotification("Password must contain a number", 400, "Password")
];
_notificationContext.AddRange(notificationBatch);

// Retrieve all raw notifications currently in the context
IReadOnlyCollection<DomainNotification> rawNotifications = _notificationContext.Notifications;

GetStatusCode() returns the highest code, not the first

With notifications carrying different status codes, GetStatusCode() returns the maximum, and 200 OK when the context is empty. So a 400 and a 422 together yield 422. That is a deliberate choice — the more specific code wins — but it means the response code does not necessarily match the first notification added.

4. Handling Notifications in Controllers/Middleware

[ApiController]
[Route("[controller]")]
public class UsersController : ControllerBase
{
    private readonly IDomainNotificationContext _notificationContext;

    public UsersController(IDomainNotificationContext notificationContext)
    {
        _notificationContext = notificationContext;
    }

    [HttpPost]
    public IActionResult Create(UserDto user)
    {
        // Call service...

        if (_notificationContext.HasNotifications)
        {
            return StatusCode(_notificationContext.GetStatusCode(), _notificationContext.GetMessages());
        }

        return Ok();
    }
}

📄 License

MIT License.