Node.js Express MongoDB backend API setup

Node.js Express MongoDB Quick Reference Guide

Quick Start Commands

# Initialize project
npm init -y

# Install dependencies
npm install express mongoose

# Start MongoDB (Mac/Linux)
mongod

# Run server
node index.js

📦 Essential Imports

const express = require('express');
const mongoose = require('mongoose');
const fs = require('fs');

🔌 MongoDB Connection

mongoose.connect('mongodb://127.0.0.1:27017/nodeWebServer')
  .then(() => console.log('MongoDB Connected'))
  .catch(err => console.log('Error:', err));

📊 Schema Definition

const userSchema = new mongoose.Schema({
  firstName: { type: String, required: true },
  lastName: String,
  email: { type: String, required: true, unique: true },
  jobTitle: String,
  gender: String
}, { timestamps: true });

const User = mongoose.model('user', userSchema);

⚙️ Middleware Setup

// Body parsers
app.use(express.urlencoded({ extended: false }));
app.use(express.json());

// Custom logging
app.use((req, res, next) => {
  const log = `${new Date().toISOString()} - ${req.ip} ${req.method} - ${req.path}\n`;
  fs.appendFile('access.log', log, (err) => {
    if (err) console.error('Logging error:', err);
  });
  next();
});

📡 API Endpoints Cheat Sheet

GET All Users (HTML)

app.get('/users', async (req, res) => {
  const allUsers = await User.find({});
  const html = `<ul>${allUsers.map(user => `<li>${user.firstName} - ${user.email}</li>`).join('')}</ul>`;
  res.send(html);
});

GET All Users (JSON)

app.get('/api/users', async (req, res) => {
  const allUsers = await User.find({});
  res.json(allUsers);
});

GET Single User

app.get('/api/users/:id', async (req, res) => {
  const user = await User.findById(req.params.id);
  if (!user) return res.status(404).json({ error: 'User not found' });
  res.json(user);
});

POST Create User

app.post('/api/users', async (req, res) => {
  const body = req.body;
  
  if (!body.first_name || !body.email) {
    return res.status(400).json({ error: 'First name and email required' });
  }

  const result = await User.create({
    firstName: body.first_name,
    lastName: body.last_name,
    email: body.email,
    gender: body.gender,
    jobTitle: body.job_title
  });

  res.status(201).json({ message: 'Success', user: result });
});

PATCH Update User

app.patch('/api/users/:id', async (req, res) => {
  await User.findByIdAndUpdate(req.params.id, req.body);
  res.json({ message: 'User updated successfully' });
});

DELETE User

app.delete('/api/users/:id', async (req, res) => {
  await User.findByIdAndDelete(req.params.id);
  res.json({ message: 'User deleted successfully' });
});

🌐 Server Startup

const PORT = 3000;
app.listen(PORT, () => {
  console.log(`Server running on http://localhost:${PORT}`);
});

🧪 Testing with cURL

# Get all users
curl http://localhost:3000/api/users

# Create user
curl -X POST http://localhost:3000/api/users \
  -H "Content-Type: application/json" \
  -d '{"first_name":"John","last_name":"Doe","email":"john@example.com","gender":"Male","job_title":"Developer"}'

# Get single user
curl http://localhost:3000/api/users/<USER_ID>

# Update user
curl -X PATCH http://localhost:3000/api/users/<USER_ID> \
  -H "Content-Type: application/json" \
  -d '{"jobTitle":"Senior Developer"}'

# Delete user
curl -X DELETE http://localhost:3000/api/users/<USER_ID>

🔍 Mongoose Query Methods

// Find all
User.find({})

// Find by ID
User.findById(id)

// Find one by criteria
User.findOne({ email: 'john@example.com' })

// Create
User.create({ firstName: 'John', email: 'john@example.com' })

// Update by ID
User.findByIdAndUpdate(id, { firstName: 'Jane' })

// Delete by ID
User.findByIdAndDelete(id)

// Count documents
User.countDocuments({})

⚡ Common Patterns

Error Handling

app.get('/api/users', async (req, res) => {
  try {
    const users = await User.find({});
    res.json(users);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

Validation

if (!req.body.email) {
  return res.status(400).json({ error: 'Email is required' });
}

Response Status Codes

res.status(200).json({ data });     // OK
res.status(201).json({ data });     // Created
res.status(400).json({ error });    // Bad Request
res.status(404).json({ error });    // Not Found
res.status(500).json({ error });    // Server Error

📝 HTTP Status Codes Reference

Code Meaning Usage 200 OK Successful GET, PATCH, DELETE 201 Created Successful POST (resource created) 400 Bad Request Invalid request data 404 Not Found Resource doesn’t exist 500 Internal Server Error Server-side error

🛠️ Useful npm Scripts

Add to package.json:

{
  "scripts": {
    "start": "node index.js",
    "dev": "nodemon index.js"
  }
}

Then install nodemon for auto-restart:

npm install --save-dev nodemon
npm run dev

🔐 Environment Variables (Production)

// Install dotenv
npm install dotenv

// .env file
PORT=3000
MONGODB_URI=mongodb://127.0.0.1:27017/nodeWebServer

// index.js
require('dotenv').config();
const PORT = process.env.PORT || 3000;
mongoose.connect(process.env.MONGODB_URI);

📦 Project Structure (Advanced)

node-web-server/
├── config/
│   └── database.js
├── controllers/
│   └── userController.js
├── models/
│   └── User.js
├── routes/
│   └── userRoutes.js
├── middleware/
│   └── logger.js
├── .env
├── index.js
└── package.json

🚀 Deployment Checklist

[ ] Use environment variables
[ ] Add error handling middleware
[ ] Implement input validation
[ ] Add authentication (JWT)
[ ] Use HTTPS
[ ] Set up CORS
[ ] Add rate limiting
[ ] Enable compression
[ ] Set security headers (helmet)
[ ] Add logging (winston/morgan)
[ ] Set up monitoring
[ ] Create API documentation

💡 Tips & Best Practices

Always use async/await for database operations
Never expose sensitive data in error messages
Validate input before processing
Use appropriate status codes
Log all errors for debugging
Keep routes organized in separate files
Use environment variables for configuration
Add comments to complex code
Test your APIs thoroughly
Keep dependencies updated

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