ASP.NET Core Web API Development with Memento Pattern

Introduction

To implement the Memento Design Pattern in an ASP.NET Core Web API with a 3-tier architecture, you can create a simple Ticket Management system with complete CRUD (Create, Read, Update, Delete) logic. The three layers in this architecture are:

1. Presentation Layer (API Controllers)
2. Business Logic Layer (Service)
3. Data Access Layer (Repository)

Here are the steps to create a complete Ticket Management system using the Memento Design Pattern:

1. Create a new ASP.NET Core Web API project

You can create a new ASP.NET Core Web API project using Visual Studio or the dotnet new command.

2. Define the Model

Create a Ticket class to represent the Ticket entity. This class should include properties like ID, Title, Description, and any other relevant fields.

//Sardar Mudassar Ali Khan
public class Ticket
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string Description { get; set; }
}

3. Create the Data Access Layer (Repository)

Create a repository to handle data operations. This layer is responsible for CRUD operations on the Ticket objects.

// Sardar Mudassar Ali Khan
public interface ITicketRepository
{
    Ticket GetTicket(int id);
    List<Ticket> GetTickets();
    void AddTicket(Ticket ticket);
    void UpdateTicket(Ticket ticket);
    void DeleteTicket(int id);
}

4. Create the Business Logic Layer (Service)

Create a service to handle business logic. This layer will interact with the repository and manage the Memento pattern.

// Sardar Mudassar Ali Khan
public class TicketService
{
    private ITicketRepository _repository;
    private List<Memento> _history = new List<Memento>();

    public TicketService(ITicketRepository repository)
    {
        _repository = repository;
    }

    public Ticket GetTicket(int id)
    {
        return _repository.GetTicket(id);
    }

    public List<Ticket> GetTickets()
    {
        return _repository.GetTickets();
    }

    public void AddTicket(Ticket ticket)
    {
        _repository.AddTicket(ticket);
        _history.Add(new Memento(ticket)); // Save the state
    }

    public void UpdateTicket(int id, Ticket newTicket)
    {
        var oldTicket = _repository.GetTicket(id);
        _repository.UpdateTicket(newTicket);
        _history.Add(new Memento(oldTicket)); // Save the state
    }

    public void DeleteTicket(int id)
    {
        var deletedTicket = _repository.GetTicket(id);
        _repository.DeleteTicket(id);
        _history.Add(new Memento(deletedTicket)); // Save the state
    }

    public Ticket RestoreTicket(int index)
    {
        if (index >= 0 && index < _history.Count)
        {
            var memento = _history[index];
            _repository.UpdateTicket(memento.GetState());
            return memento.GetState();
        }
        return null;
    }
}

5. Implement the Memento Pattern

Create a Memento class to store the state of a Ticket.

//Sardar Mudassar Ali Khan
public class Memento
{
    private Ticket _state;

    public Memento(Ticket state)
    {
        _state = state;
    }

    public Ticket GetState()
    {
        return _state;
    }
}

6. Create the API Controllers (Presentation Layer)

Implement API controllers for CRUD operations. These controllers should use the TicketService to interact with the business logic layer.

// Sardar Mudassar Ali Khan
[Route("api/tickets")]
[ApiController]
public class TicketController : ControllerBase
{
    private TicketService _service;

    public TicketController(TicketService service)
    {
        _service = service;
    }

    // GET api/tickets
    [HttpGet]
    public ActionResult<List<Ticket>> Get()
    {
        return _service.GetTickets();
    }

    // GET api/tickets/5
    [HttpGet("{id}")]
    public ActionResult<Ticket> Get(int id)
    {
        return _service.GetTicket(id);
    }

    // POST api/tickets
    [HttpPost]
    public IActionResult Post([FromBody] Ticket ticket)
    {
        _service.AddTicket(ticket);
        return Ok();
    }

    // PUT api/tickets/5
    [HttpPut("{id}")]
    public IActionResult Put(int id, [FromBody] Ticket ticket)
    {
        _service.UpdateTicket(id, ticket);
        return Ok();
    }

    // DELETE api/tickets/5
    [HttpDelete("{id}")]
    public IActionResult Delete(int id)
    {
        _service.DeleteTicket(id);
        return Ok();
    }

    // Restore a Ticket to a previous state
    [HttpPut("{id}/restore/{index}")]
    public IActionResult Restore(int id, int index)
    {
        var restoredTicket = _service.RestoreTicket(index);
        if (restoredTicket != null)
        {
            return Ok();
        }
        return NotFound();
    }
}

7. Configure Dependency Injection

In your Startup.cs class, configure dependency injection for the ITicketRepository, TicketService, and any other dependencies.

// Sardar Mudassar Ali Khan
public void ConfigureServices(IServiceCollection services)
{
    services.AddScoped<ITicketRepository, TicketRepository>();
    services.AddScoped<TicketService>();
    // Add other services as needed
}

8. Implement the Data Access Layer (Repository)

Implement the ITicketRepository interface using a data store like a database or an in-memory collection.

9. Configure Routing

Ensure that your API routes are properly configured in Startup. cs.

10. Run and Test

You can now run your ASP.NET Core Web API and use tools like Postman or Swagger to test the CRUD operations and the Memento pattern for restoring ticket states.

This is a basic implementation of the Memento Design Pattern in an ASP.NET Core Web API with a 3-tier architecture. You can expand on this foundation and add more features as needed for your Ticket Management system.

Conclusion

You have a complete solution for an ASP.NET Core Web API with a 3-tier architecture and the Memento Design Pattern integrated for secure and reliable ticket management. This architecture enables you to create, retrieve, update, and delete tickets while preserving the historical states of the tickets. The suggested title, TicketGuardian - ASP.NET Core Web API with Memento Pattern for Secure Ticket Management, highlights the core features and security aspects of the application.

You can further customize and expand this foundation to meet your specific requirements and enhance the ticket management system as needed. This design pattern provides a robust way to track and restore the state of tickets, making it a valuable addition to your ASP.NET Core Web API project.