URL Shortener API

A simple and efficient URL shortening service built with ASP.NET Core, Entity Framework, and Redis caching.

Features

• Shorten long URLs into compact 7-character codes
• Redis caching for fast redirects
• SQL Server database for persistent storage
• Automatic unique code generation

Prerequisites

• .NET 8.0 or higher
• SQL Server
• Redis

Configuration

Update your appsettings.json with the following connection strings:

{
  "ConnectionStrings": {
    "DefaultConnection": "Your SQL Server connection string",
    "Redis": "Your Redis connection string"
  }
}

API Endpoints

1. Shorten URL

Creates a shortened URL from a long URL.

Endpoint: POST /api/shorten

Request Body:

{
  "url": "https://example.com/very/long/url/that/needs/shortening"
}

Response:

https://yourdomain.com/api/abc123X

Status Codes:

• 200 OK - URL successfully shortened
• 400 Bad Request - Invalid URL format

---

2. Redirect to Original URL

Redirects from a short code to the original long URL.

Endpoint: GET /api/{code}

Example:

GET /api/abc123X

Response:

• Redirects to the original long URL
• Uses Redis cache for improved performance (10-minute TTL)

Status Codes:

• 302 Found - Successful redirect
• 404 Not Found - Short code does not exist

Usage Examples

Creating a Short URL

curl -X POST https://yourdomain.com/api/shorten \
  -H "Content-Type: application/json" \
  -d '{"url": "https://example.com/long-url"}'

Using a Short URL

Simply visit the shortened URL in your browser or make a GET request:

curl -L https://yourdomain.com/api/abc123X

Database Schema

ShortenedUrls Table:

• Id (Guid) - Primary key
• LongUrl (string) - Original URL
• ShortUrl (string) - Complete shortened URL
• Code (string, 7 chars) - Unique short code (indexed)
• CreatedOnUtc (DateTime) - Creation timestamp

Performance

• Redis caching reduces database queries for frequently accessed URLs
• Cache TTL: 10 minutes
• Unique code generation with collision detection