Frontend Components

Relevant source files

The following files were used as context for generating this wiki page:

• MercaditoMovil.Infrastructure/Repositories/CsvUserRepository.cs
• Mercadito.Domain/Entities/User/User.cs
• MercaditoMovil.Application/Service/AuthService.cs
• MercaditoMovil/Controllers/LoginController.cs
• MercaditoMovil.Application/Validators/UserValidator.cs
• Mercadito.Domain/Interfaces/Interface1.cs
• MercaditoMovil.Application/Features/UserManagement/IAuthService.cs
• MercaditoMovil.Infrastructure/Tools/Scripts/create_csvs.py
• MercaditoMovil/Program.cs
• MercaditoMovil/Views/Form1.Designer.cs
• MercaditoMovil/Views/Form1.cs

This document outlines the architecture and implementation of the user authentication and management system within the MercaditoMovil project. This system is responsible for handling user registration, login, data validation, and persistence. The backend is built using a layered architecture in .NET, with user data stored in CSV files.

The application's entry point is a Windows Forms application, but the core logic for user management is decoupled from the UI, residing in separate Application, Domain, and Infrastructure layers.

System Architecture

The user management feature follows a clean architecture pattern, separating concerns into distinct layers. The Presentation layer (Windows Forms) interacts with the Application layer, which contains business logic. The Application layer uses interfaces defined in the Domain layer to interact with the Infrastructure layer, which handles data persistence.

This diagram illustrates the high-level interaction between the major components.

Class Relationships

The following diagram shows the dependency and implementation relationships between the key classes and interfaces involved in authentication.

Data Model and Persistence

User Entity

The User entity represents an application user. It is a plain C# class with properties for user data. The constructor ensures that all string properties are non-null, defaulting to empty strings if null is passed.

Sources: Mercadito.Domain/Entities/User/User.cs

Property	Type	Description
UserId	string	Unique identifier for the user.
Username	string	The user's login name.
Password	string	The user's password (stored in plain text).
FirstName	string	User's first name.
LastName1	string	User's first last name.
LastName2	string	User's second last name.
NationalId	string	National identification number.
Email	string	User's email address.
Phone	string	User's phone number.
ExactAddress	string	User's full street address.
Province	string	Province of residence.
Canton	string	Canton of residence.
District	string	District of residence.
MarketId	string	ID of the market associated with the user. Defaults to MKT-000.

Sources: Mercadito.Domain/Entities/User/User.cs:7-41

CSV Storage

User data is stored in a CSV file located at MercaditoMovil.Infrastructure/DataFiles/People/users.csv. The CsvUserRepository class is responsible for all read and write operations on this file.

The structure of the users.csv file is defined by a header row.

This diagram represents the columns in the users.csv file.
Sources: MercaditoMovil.Infrastructure/Repositories/CsvUserRepository.cs:15-16, MercaditoMovil.Infrastructure/Tools/Scripts/create_csvs.py:149-150

CsvUserRepository

This class implements the IUserRepository interface and handles the persistence of User entities in a CSV file.

Method	Description
GetByUsername(string username)	Performs a sequential scan of the CSV file to find a user by their username (case-insensitive). It uses Microsoft.VisualBasic.FileIO.TextFieldParser to correctly handle quoted fields.
Add(User user, out string error)	Appends a new user record to the CSV file. It ensures the file and its directory exist, and writes the header if the file is new.
EnsureFile()	A private helper that creates the directory and file if they don't exist. It also prepends the header to an existing file if it's missing.
Q(string value)	A private static helper to quote and escape a string value for safe inclusion in a CSV row.

Sources: MercaditoMovil.Infrastructure/Repositories/CsvUserRepository.cs

Business Logic

Authentication Service (AuthService)

The AuthService class orchestrates the login and registration processes. It depends on IUserRepository for data access and UserValidator for input validation.

Sources: MercaditoMovil.Application/Service/AuthService.cs

Login Flow

The login process validates user input, retrieves the user from the repository, and compares the provided password with the stored password.

Registration Flow

The registration process validates the new user's data, checks for duplicate usernames, and then adds the new user to the repository.

Input Validation (UserValidator)

The static UserValidator class provides centralized validation logic for user-related operations.

• ValidateLogin: Checks that username and password are not null or whitespace.
• ValidateRegister: Checks that the User object is not null and that required fields (Username, Password, FirstName, NationalId, Email) are not empty.

Sources: MercaditoMovil.Application/Validators/UserValidator.cs:11-42

Presentation Layer

The presentation layer is a Windows Forms application.

• Program.cs: The main entry point for the application, which initializes and runs Form1.
• Form1.cs / Form1.Designer.cs: A basic, currently empty, Windows Form. It is intended to be the main window of the application.
• LoginController.cs: Acts as a bridge between the UI (forms) and the AuthService. It translates UI events into calls to the application service and returns results to be displayed.

Sources: MercaditoMovil/Program.cs, MercaditoMovil/Views/Form1.cs, MercaditoMovil/Controllers/LoginController.cs

Data Generation

A Python script, create_csvs.py, is provided to generate mock data for the application, including the users.csv file.

Key functions in this script related to user generation:

• gen_users(): Orchestrates the creation of user data, including two fixed users and 28 randomly generated ones.
• rand_username(): Generates a plausible username from a first and last name.
• rand_email(): Generates a plausible email address.
• cr_id(): Generates a realistic 9-digit national ID number.
• pick_market(): Assigns a market ID based on the user's location.

The script writes the generated data to MercaditoMovil.Infrastructure/DataFiles/People/users.csv.

Sources: MercaditoMovil.Infrastructure/Tools/Scripts/create_csvs.py:148-210