ATM [Hexagonal Architecture]

Implementation of an ATM system with a Web API interface using ASP.NET Controllers and in-memory storage.

Functionality

• creating a user session using AccountNumber + PIN
• creating an administrator session using SystemPassword + AccountNumber
• creating an account, available only through an admin session
• viewing the account balance
• depositing money into an account
• withdrawing money
• viewing transaction history

Any account-related operation creates a record in the transaction history.

Architecture

The project follows the hexagonal architecture approach:

• Domain — domain model and value objects
• Application — business logic / use cases through ports
• Application.Abstractions — abstractions such as repositories, providers, and similar components
• Application.Contracts — request/response contracts and operation results
• Infrastructure — implementations of abstractions, including in-memory repositories, and DI registration
• Presentation — ASP.NET Web API Controllers and HTTP-to-port mapping

The layers are connected using Microsoft.Extensions.DependencyInjection.

Each module provides extension methods for dependency registration:

• builder.Services.AddApplication();
• builder.Services.AddInfrastructure();

System Password Configuration

The system password is read through ISystemPasswordProvider, implemented in Atm.Presentation.Common.SystemPasswordProvider, and is taken from the configuration.

appsettings.json:

{
  "SystemAuth": {
    "SystemPassword": "your_password_here"
  }
}