URL Shortener

🔗 A simple and efficient URL shortening service built with Node.js, Express, and MongoDB.

📋 Table of Contents

• 🔹 Features
• 🔹 Tech Stack
• 🔹 Prerequisites
• 🔹 Code Style
• 🔹 Installation
• 🔹 Usage
• 🔹 API Endpoints
• 🔹 Database Schema (MongoDB)
• 🔹 Project Structure
• 🔹 How it Works
• 🔹 Note

🔹 Features

• 🚀 Fast URL shortening service
• 🔄 URL validation before shortening
• 📊 MongoDB for persistent storage
• 🎯 Custom short code generation
• 🔀 Automatic redirection to original URLs
• ⚡ Built with modern ES6+ modules
• 🛠️ Development mode with auto-reload using Nodemon

🔹 Tech Stack

• Runtime: Node.js
• Framework: Express v5.1.0
• Database: MongoDB (via Mongoose v8.18.3)
• Validation: valid-url v1.0.9
• Environment Variables: dotenv v17.2.3
• Dev Tools: Nodemon v3.1.10

🔹 Prerequisites

Before you begin, ensure you have the following installed:

• Node.js (v14 or higher)
• npm or yarn
• MongoDB (local instance or MongoDB Atlas account)

🔹 Code Style

This project uses ES6+ modules. Make sure to:

• Use import/export syntax instead of require/module.exports

🔹 Installation

1. Clone the repository:

git clone https://github.com/Amitrajit007/url-shortner
cd URL-SHORTENER

2. Install dependencies:

npm install

3. Set up environment variables:

Create a .env file in the root directory:

PORT=5000
MONGO_URI=<your-mongodb-connection-string>
BASE_URL=http://localhost:5000
# Add any other environment variables your app needs

4. Start the development server:

npm start

The server will start on http://localhost:5000 (or the port specified in your .env file make sure to change the BASE_URL if u change the PORT.).

🔹 Usage

Creating a Short URL

Send a POST request to create a shortened URL:

curl -X POST http://localhost:5000/url \
  -H "Content-Type: application/json" \
  -d '{"url": "https://www.example.com/very-long-url"}'

Accessing a Shortened URL

Simply navigate to:

http://localhost:5000/{shortCode}

You'll be automatically redirected to the original URL.

🔹 API Endpoints

POST /url

Create a new shortened URL.

Request Body:

{
  "url": "https://www.example.com/long-url"
}

• or

{
  "url": "https://www.example.com/long-url",
  "expiryDays": 1
}

Note: expiryDays: 1 means the URL will expire after 1 day it can be any number.

Response:

{
  "success": true,
  "data": {
    "id": 18,
    "originalUrl": "https://www.example.com/long-url",
    "shortCode": "i",
    "shortUrl": "http://localhost:5000/i",
    "clicks": 0,
    "expiryDays": 1,
    "expiresAt": "2025-10-06T20:48:53.410Z"
  }
}

GET /:shortCode

Redirect to the original URL associated with the short code.

GET /redirect

Special endpoint for testing/Easter egg functionality.

🔹 Database Schema (MongoDB)

Field	Type	Description
id	Number	Auto-increment ID
originalUrl	String	Original long URL
shortCode	String	Short code (Base62)
shortUrl	String	Generated short URL
clicks	Number	Number of times URL was clicked
expiryDays	Number	Optional: number of days before expiry
expiresAt	Date	Calculated expiry date (TTL index)
createdAt	Date	Document creation timestamp
updatedAt	Date	Document last update timestamp

🔹 Project Structure

url-shortener/
├── server/
│ └── src/
│ ├── app.js # Main application entry point
│ ├── config/
│ │ └── url.config.js # Database configuration
│ ├── controllers/
│ │ ├── shorturlCreate.controller.js # URL shortening logic
│ │ ├── redirect.controller.js # Redirection handling
│ │ └── X.controller.js # Easter egg handling
│ │
│ ├── model/
│ │ └── url.model.js # URL schema and model
│ ├── data/
│ │ └── repository.js # Data access layer
│ ├── routes/
│ │ ├── creatUrl.route.js # URL creation route
│ │ ├── redirect.route.js # Redirection route
│ │ └── X.route.js # Easter egg route
│ └── middlewares/
│ └── validator.middleware.js # URL validation middleware
├── .env # Environment variables (not in repo)
├── .gitignore # Git ignore file
├── nodemon.json # Nodemon configuration
├── package.json # Project dependencies
├── package-lock.json # Locked dependencies
└── README.md # Project documentation

🔹 How it Works

1. User sends a long URL to /url.

2. Backend generates a shortCode and stores it in MongoDB along with optional expiry.

3. MongoDB automatically deletes expired URLs (TTL index on expiresAt).

4. When someone visits /:shortCode, the server redirects to the original URL if it’s valid and not expired.

🔹 Note:

• Test scripts need to be configured in package.json.
• Do not try to shorten a URL that is already shortened by this service.
• TTL deletion is handled automatically by MongoDB.
• Expired URLs will return HTTP 410 (Gone).
• Clicks are tracked in the clicks field in the database.