Centivo User API

A Node.js Express API that connects to MongoDB and retrieves user data with age-based filtering.

Approach

This solution implements a RESTful API using Express.js with MongoDB integration. The /users/:id endpoint validates ObjectId format, queries the database for users over 21 years old, and returns appropriate HTTP status codes. The API includes error handling for invalid ObjectIds and gracefully manages database connection failures.

Features

• ✅ GET endpoint at /users/:id that accepts user ID as route parameter
• ✅ Queries MongoDB "users" collection for matching _id
• ✅ Returns user details in JSON format
• ✅ Returns 404 Not Found for non-existent users
• ✅ Gracefully handles invalid ObjectId errors (400 Bad Request)
• ✅ Unique twist: Only returns users where age > 21
• ✅ Health check endpoint at /health
• ✅ CORS enabled for cross-origin requests
• ✅ Environment variable configuration

Setup Instructions

1. Install dependencies:

   npm install

2. Configure environment variables:

   cp env.example .env
   # Edit .env with your MongoDB connection details

3. Start MongoDB: Make sure MongoDB is running on your system or use a cloud MongoDB instance.

4. Run the application:

   # Development mode with auto-restart
   npm run dev
   
   # Production mode
   npm start

API Endpoints

GET /users/:id

Retrieves a user by ID (only if age > 21)

Parameters:

• id (string): MongoDB ObjectId of the user

Responses:

• 200 OK: User found and returned
• 400 Bad Request: Invalid ObjectId format
• 404 Not Found: User not found or user is 21 or younger
• 500 Internal Server Error: Server error

Example Response:

{
  "_id": "507f1f77bcf86cd799439011",
  "name": "John Doe",
  "email": "johndoe@email.com",
  "age": 30
}

GET /health

Health check endpoint

Response:

{
  "status": "OK",
  "message": "Server is running"
}

Sample Data

To test the API, you can insert sample data into your MongoDB collection:

// In MongoDB shell or MongoDB Compass
use centivo_db

db.users.insertMany([
  {
    "_id": ObjectId("507f1f77bcf86cd799439011"),
    "name": "John Doe",
    "email": "johndoe@email.com",
    "age": 30
  },
  {
    "_id": ObjectId("507f1f77bcf86cd799439012"),
    "name": "Jane Smith",
    "email": "janesmith@email.com",
    "age": 25
  },
  {
    "_id": ObjectId("507f1f77bcf86cd799439013"),
    "name": "Bob Wilson",
    "email": "bobwilson@email.com",
    "age": 19
  }
])

Testing

Test the API with curl or any HTTP client:

# Test with valid user ID (age > 21)
curl http://localhost:3000/users/507f1f77bcf86cd799439011

# Test with valid user ID (age <= 21) - should return 404
curl http://localhost:3000/users/507f1f77bcf86cd799439013

# Test with invalid ObjectId - should return 400
curl http://localhost:3000/users/invalid-id

# Test health endpoint
curl http://localhost:3000/health