JeBalance — N-tier application

The project

JeBalance is a tax fraud reporting platform, built for an N-tier architecture course. Citizens file a report; the tax administration processes it through role-protected endpoints.

Features

• File a report — suspect identity, full address, offence type (tax evasion or income concealment) and the country involved.
• Look up a report — retrieve a report by its identifier.
• Administrative tracking — list of unanswered reports, restricted to accounts holding the adminFiscale role.
• Protected persons management — promote an individual to VIP status and back to standard, gated by an administrator token.

Architecture

The application follows a Domain Driven Design architecture on the ABP framework, split across three layers.

Web layer — HttpApi. The entry point for requests, and therefore where authentication is configured. JWT validation is declared here:

context.Services.AddAuthentication(options =>
{
    options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
})
.AddJwtBearer(options =>
{
    options.TokenValidationParameters = new TokenValidationParameters
    {
        ValidateIssuerSigningKey = true,
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(jwtSettings.IssuerSigningKey)),
        ValidateIssuer = true,
        ValidIssuer = jwtSettings.Issuer,
        ValidateAudience = true,
        ValidAudience = jwtSettings.Audience,
        ValidateLifetime = true,
    };
});

Application layer — business logic. AppService interfaces, DTOs and models are declared on the Application Contract side, implementations on the Application side. A neat ABP trait: inheriting from ApplicationService generates REST controllers automatically from method names, without writing a single controller.

public class DenonciationAppService : ApplicationService, IDenonciationAppService, ITransientDependency

Protecting an endpoint then comes down to one attribute:

[Authorize(Roles = "adminFiscale")]

Entity ↔ DTO mapping is delegated to AutoMapper, which needs no configuration as long as properties share the same names.

Domain and infrastructure layers. Entities inherit from Entity<Guid>, handing indexing and unique keys to ABP. The DbContext, repositories and Entity Framework Core migrations live in the EntityFrameworkCore project:

public interface IEfCoreDenonciationRepository : IRepository<Entities.Denonciation, Guid>
{
    Task<Guid> RegisterDenonciationAsync(Entities.Denonciation denonciation);
    Task<Entities.Denonciation> GetDenonciationAsync(Guid id);
    Task<List<Entities.Denonciation>> ListDenonciationNonTraiteAsync();
}

Inheriting from IRepository<Entity, Guid> provides CRUD operations without rewriting them.

Outcome

All endpoints are functional and tested. Time ran short on the Blazor front end, however: report creation, the administrative response and the VIP status change are driven through the API rather than from the UI.