Afri-Mart Backend

This is a Node.js/Express backend for an African food marketplace application. Let me walk you through the key components:

Architecture Overview

The codebase follows a modular architecture with clear separation of concerns:

1. API Layer (/api)

• Auth Module: Handles user authentication and authorization

  • JWT-based authentication
  • Role-based access control (admin, student, instructor roles)
  • Password hashing using bcryptjs

• Items Module: Manages food items/products

  • CRUD operations for food items
  • Each item has title, price, quantity, and image URL

• Users Module: Handles user management

  • User creation and retrieval
  • Role management
  • Uses transactions for data integrity when creating users

2. Controllers (/controllers)

• Separates business logic from routes
• Handles error responses and success states
• Currently implements items-related operations

3. Data Layer (/data)

• Uses Knex.js as the query builder
• Configurable for different environments (development, testing, production)
• Supports both PostgreSQL and SQLite databases

4. Database Schema (/migrations)

Two main tables:

1. Users/Roles Tables (20220308130032_initial-migration.js)

   • Many-to-one relationship between users and roles
   • Role-based authorization system

2. Items Table (20211115082418_items.js)

   • Stores food items with properties like:
     • Title (unique)
     • Price
     • Quantity
     • Image URL

5. Seed Data (/seeds)

• Includes cleanup utility
• Populates initial roles (admin, student, instructor)
• Creates test users
• Adds sample food items (African dishes like Jollof Rice)

Key Technical Features

1. Security

   • JWT authentication
   • Password hashing
   • Role-based access control
   • Helmet for HTTP security headers

2. Database

   • Knex migrations for version control
   • Transaction support
   • Relationship management
   • Data seeding

3. API Design

   • RESTful endpoints
   • Middleware for authentication and validation
   • Error handling
   • Response standardization

Development Features

• Environment configuration using dotenv
• Hot reloading with nodemon
• Database migration and seeding scripts
• ESLint for code quality

This architecture allows for scalability, maintainability, and separation of concerns while providing a secure and efficient API for the frontend application.

Setup and Running Instructions

Prerequisites

• Node.js (v12 or higher)
• npm or yarn
• PostgreSQL (for production) or SQLite (for development)

Installation Steps

1. Clone the repository

git clone https://github.com/Afri-Mart/Backend.git
cd Backend

2. Install dependencies

npm install

3. Set up environment variables Create a .env file in the root directory:

PORT=5001
JWT_SECRET=your_secret_here
NODE_ENV=development

4. Set up the database

# Run migrations to create database tables
npm run migrate

# Seed the database with initial data
npm run seed

Running the Application

1. Development mode (with hot reload)

npm run server

2. Production mode

npm start

The server will start on http://localhost:5001

Available Scripts

• npm start - Runs the server in production mode
• npm run server - Runs the server with nodemon for development
• npm run migrate - Runs database migrations
• npm run rollback - Rolls back the last migration
• npm run seed - Seeds the database with initial data
• npm run reset - Rolls back, migrates, and seeds the database (full reset)

Testing the API

Authentication Endpoints

# Register a new user
POST http://localhost:5001/api/auth/register
{
    "username": "testuser",
    "password": "password123",
    "role_name": "student"
}

# Login
POST http://localhost:5001/api/auth/login
{
    "username": "testuser",
    "password": "password123"
}

Items Endpoints

# Get all items
GET http://localhost:5001/api/items

# Get specific item
GET http://localhost:5001/api/items/:id

Users Endpoints (Requires Authentication)

# Get all users (requires auth token)
GET http://localhost:5001/api/users

# Get specific user (requires admin role)
GET http://localhost:5001/api/users/:user_id

Database Reset

If you need to reset the database to its initial state:

npm run reset

Common Issues and Solutions

1. Port Already in Use If you see EADDRINUSE error:

# Change the port in package.json scripts
"start": "PORT=5002 node index.js",
"server": "PORT=5002 nodemon index.js"

2. Database Connection Issues

• Ensure PostgreSQL is running (if using PostgreSQL)
• Check database credentials in knexfile.js
• For development, SQLite database will be created automatically

Project Structure

├── api/
│   ├── auth/         # Authentication related files
│   ├── items/        # Items related files
│   ├── users/        # Users related files
│   └── secrets/      # Environment secrets
├── controllers/      # Business logic
├── data/            # Database configuration
├── migrations/      # Database migrations
├── seeds/           # Seed data
└── package.json     # Project dependencies and scripts

Deployment

The application is ready for deployment on platforms like Heroku, AWS, or any Node.js hosting service. Make sure to:

1. Set appropriate environment variables
2. Configure the database connection
3. Run migrations on deployment
4. Set up proper security measures (HTTPS, etc.)