minimal-api-patterns

name: minimal-api-patterns description: Best practices for defining Endpoints, DTOs, and Validators using ASP.NET Core Minimal APIs.

Minimal API Patterns

Role Responsibilities

As an API Contract Guardian, you are responsible for:

• Contracts: Defining clear Request/Response DTOs in GloboTicket.Application/DTOs.
• Endpoints: Implementing MapGroup definitions in GloboTicket.API/Endpoints/.
• Services: Implementing Application Services that orchestrate Domain Entities.
• Validation: Ensuring all inputs are validated before processing.

Endpoint Structure

Grouping

• Use MapGroup to organize related endpoints.
• Apply common middleware (Auth, Versioning) at the group level.

public static WebApplication MapVenueEndpoints(this WebApplication app)
{
    var venues = app.MapGroup("/api/venues")
        .RequireAuthorization()
        .WithTags("Venues");

    venues.MapGet("/", GetAllVenues);
    return app;
}

DTO Pattern

Separation of Concerns

• NEVER return Domain Entities directly from an endpoint.
• Always map to a specific DTO.
• Use record types for DTOs for immutability.

// Good
public record VenueDto(Guid Id, string Name, string Location);

// Bad
public class Venue : Entity { ... } // Do not return this!

Service Layer Integration

Injection

• Inject Application Services (IVenueService) into endpoint delegates.
• Keep endpoint logic thin; delegate business logic to the Service.

venues.MapPost("/", async (CreateVenueDto dto, IVenueService service) => 
{
    var result = await service.CreateAsync(dto);
    return Results.Created($"/api/venues/{result.Id}", result);
});