url-shortener

A lightweight self-hosted URL shortener written in Go.

Current implementation details:

• HTTP server built with Gorilla Mux
• SQLite storage (file at internal/database/url-shortener.db)
• Automatic SQL migrations on startup
• API-key protected create/delete endpoints
• Plain-text request bodies

Requirements

• Go
• SQLite support via github.com/mattn/go-sqlite3 (CGO-enabled build environment)

Configuration

The app requires a .env file in the project root.

PORT=5099
API_KEY=abc123
RAND_CHARS=6 # Optional, defaults to 8 when missing.

If either value is missing, startup fails.

Run

Using make:

make run

Or directly:

go run ./cmd/url-shortener/main.go

Build binary:

make build
./bin/url-shortener

API

Base URL examples below use http://localhost:5099.

Create short URL

POST /create

Headers:

• K: <API_KEY>

Body format (plain text):

• url
• url|alias

Examples:

curl -H "K: <API_KEY>" http://localhost:5099/create -d 'example.com'

curl -H "K: <API_KEY>" http://localhost:5099/create -d 'https://example.com/docs|docs'

Behavior:

• If alias is omitted, an 8-character random alias is generated
• URLs without scheme are normalized to http://...
• Only http and https URLs are accepted

Success response:

• Status: 201 Created
• Body: <host>/<alias>

Possible errors:

• 400 Bad Request for invalid body/URL
• 401 Unauthorized for missing or invalid API key
• 500 Internal Server Error (for example, duplicate alias insertion)

Delete short URL

POST /delete

Headers:

• K: <API_KEY>

Body format (plain text):

• alias

Example:

curl -H "K: <API_KEY>" http://localhost:5099/delete -d 'docs'

Success response:

• Status: 200 OK
• Body: <alias> deleted

Possible errors:

• 401 Unauthorized for missing or invalid API key
• 500 Internal Server Error if alias does not exist or delete fails

Redirect

GET /{alias}

Example:

curl -i http://localhost:5099/docs

Behavior:

• Redirects using 301 Permanent Redirect
• Returns 404 if alias is not found

Storage and Migrations

• Database file: internal/database/url-shortener.db
• Migrations dir: internal/database/migrations
• Migrations run automatically when the server starts

Project Status

Current state is a working core service with create, delete, and redirect endpoints backed by SQLite.

Known limitations in current behavior:

• No structured JSON API
• Duplicate alias attempts currently surface as generic http 500 errors
• Delete for missing alias currently returns 500 rather than 404

License