Customer Management API

A RESTful API for managing customers with full CRUD operations, built with Node.js and Express.

🚀 Features

• Create new customers
• Read all customers or specific customer
• Update existing customers
• Delete customers
• Search customers by name, email, or company
• Filter customers by status
• Validation for required fields and duplicate emails
• Error handling with proper HTTP status codes

📁 Project Structure

customer-api/
├── customer_server.js      # Main API server
├── test_customer_api.js    # Automated test script
├── package.json           # Dependencies and scripts
├── README.md              # This file
└── Customer_API.postman_collection.json  # Postman collection

🛠️ Setup

1. Install Node.js

Make sure Node.js is installed:

node --version
npm --version

2. Install Dependencies

cd customer-api
npm install

This will install:

• express - Web framework for the API server
• nodemon - Auto-restart during development (optional)

🎬 Running the API

Start the Server

npm start
# or
node customer_server.js

You'll see:

╔════════════════════════════════════════╗
║   Customer Management API Started 🚀   ║
╚════════════════════════════════════════╝

📍 Server running at: http://localhost:3001
📊 API Endpoint: http://localhost:3001/api/customers

Development Mode (Auto-restart)

npm run dev
# or
nodemon customer_server.js

📊 API Endpoints

Method	Endpoint	Description
GET	/	Health check and API info
GET	/api/customers	Get all customers
GET	/api/customers/:id	Get specific customer
POST	/api/customers	Create new customer
PUT	/api/customers/:id	Update customer
DELETE	/api/customers/:id	Delete customer
GET	/api/customers/status/:status	Get customers by status
GET	/api/customers/search/:query	Search customers

🧪 Testing

Automated Testing

Run the comprehensive test suite:

npm test
# or
node test_customer_api.js

This will test all CRUD operations, validation, error handling, and edge cases.

Manual Testing with Postman

1. Create a Customer

• Method: POST
• URL: http://localhost:3001/api/customers
• Body (JSON):

{
  "name": "Ahmed Mohamed",
  "email": "ahmed@example.com",
  "phone": "+218-91-123-4567",
  "address": "Tripoli, Libya",
  "company": "Tech Solutions"
}

• Expected: 201 Created

2. Get All Customers

• Method: GET
• URL: http://localhost:3001/api/customers
• Expected: 200 OK with customer list

3. Get Specific Customer

• Method: GET
• URL: http://localhost:3001/api/customers/CUST-123...
• Expected: 200 OK with customer details

4. Update Customer

• Method: PUT
• URL: http://localhost:3001/api/customers/CUST-123...
• Body (JSON):

{
  "name": "Ahmed Mohamed Updated",
  "phone": "+218-91-999-8888"
}

• Expected: 200 OK

5. Search Customers

• Method: GET
• URL: http://localhost:3001/api/customers/search/ahmed
• Expected: 200 OK with search results

6. Delete Customer

• Method: DELETE
• URL: http://localhost:3001/api/customers/CUST-123...
• Expected: 200 OK

Testing with curl

# Create customer
curl -X POST http://localhost:3001/api/customers \
  -H "Content-Type: application/json" \
  -d '{"name":"Ahmed Mohamed","email":"ahmed@example.com","phone":"+218-91-123-4567"}'

# Get all customers
curl http://localhost:3001/api/customers

# Get specific customer
curl http://localhost:3001/api/customers/CUST-123...

# Update customer
curl -X PUT http://localhost:3001/api/customers/CUST-123... \
  -H "Content-Type: application/json" \
  -d '{"name":"Updated Name"}'

# Search customers
curl http://localhost:3001/api/customers/search/ahmed

# Delete customer
curl -X DELETE http://localhost:3001/api/customers/CUST-123...

📋 Customer Data Model

{
  "id": "CUST-1234567890-1",
  "name": "Ahmed Mohamed",
  "email": "ahmed@example.com",
  "phone": "+218-91-123-4567",
  "address": "Tripoli, Libya",
  "company": "Tech Solutions",
  "status": "active",
  "createdAt": "2024-01-15T10:30:00.000Z",
  "updatedAt": "2024-01-15T10:30:00.000Z"
}

Required Fields

• name (string) - Customer's full name
• email (string) - Customer's email address (must be unique)

Optional Fields

• phone (string) - Customer's phone number
• address (string) - Customer's address
• company (string) - Customer's company name

Auto-generated Fields

• id (string) - Unique customer ID
• status (string) - Customer status (default: "active")
• createdAt (string) - Creation timestamp
• updatedAt (string) - Last update timestamp

🔍 Advanced Features

Search Customers

Search by name, email, or company:

GET /api/customers/search/ahmed

Filter by Status

Get customers with specific status:

GET /api/customers/status/active

Validation Rules

• Name and email are required
• Email must be unique
• Phone, address, and company are optional
• Email format validation (basic)

🚨 Error Handling

The API returns appropriate HTTP status codes:

• 200 OK - Successful GET, PUT, DELETE
• 201 Created - Successful POST
• 400 Bad Request - Missing required fields
• 404 Not Found - Customer not found
• 409 Conflict - Duplicate email
• 500 Internal Server Error - Server error

Error Response Format

{
  "success": false,
  "message": "Error description",
  "requestedId": "CUST-123..." // (for 404 errors)
}

🎓 Learning Objectives

After using this API, you'll understand:

• ✅ RESTful API design principles
• ✅ HTTP methods (GET, POST, PUT, DELETE)
• ✅ HTTP status codes (200, 201, 400, 404, 409, 500)
• ✅ JSON request/response format
• ✅ Input validation and error handling
• ✅ CRUD operations in practice
• ✅ API testing strategies

🐛 Troubleshooting

"Cannot find module 'express'"

npm install

"Port 3001 already in use"

# Find and kill the process
lsof -ti:3001 | xargs kill -9

"Command not found: node"

Install Node.js from: https://nodejs.org/

Server not responding

1. Check if server is running: npm start
2. Verify port 3001 is available
3. Check console for error messages

📚 Next Steps

After mastering this API, consider:

• Adding authentication (JWT tokens)
• Database integration (MySQL, PostgreSQL)
• Input validation middleware (Joi, express-validator)
• API documentation (Swagger/OpenAPI)
• Rate limiting and security
• Unit testing with Jest
• Docker containerization

🤝 Contributing

Feel free to:

• Add new features
• Improve error handling
• Add more test cases
• Enhance documentation
• Optimize performance

📄 License

MIT License - feel free to use this code for learning and development!

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Happy coding! 🚀

customer-api