# URL Shortener

A minimal URL shortener written in pure Python 3.8+ (zero third-party dependencies) backed by SQLite.

## Quick start

### Run locally

```bash
python urlshort.py config.json
```

### Run with Docker Compose

Edit `config.json` first (especially `api_key` and `base_url`), then:

```bash
docker compose up --build
```

The SQLite database is stored in `./data/urlshort.db` on the host — it survives container restarts.

---

## Configuration (`config.json`)

| Key            | Required | Default              | Description                                  |
|----------------|----------|----------------------|----------------------------------------------|
| `base_url`     | ✅        | —                    | Public base URL used in generated short URLs |
| `short_length` | ✅        | —                    | Character length of auto-generated codes     |
| `api_key`      | ✅        | —                    | Secret key to protect write/read operations  |
| `host`         |          | `"0.0.0.0"`          | Bind address                                 |
| `port`         |          | `8080`               | Bind port                                    |
| `db_path`      |          | `"data/urlshort.db"` | Path to the SQLite database file             |

---

## Authentication

All `/api/*` endpoints require the API key.  
Pass it as a **Bearer token** in the `Authorization` header or as a query parameter:

```
Authorization: Bearer <api_key>
# or
?api_key=<api_key>
```

---

## API Reference

### `GET /`
Health check.

**Response `200`**
```json
{ "status": "ok", "service": "url-shortener" }
```

---

### `POST /api/shorten` 🔒
Create a new short URL.

**Request body**
```json
{
  "url": "https://example.com/very/long/path",
  "custom_code": "mycode"   // optional
}
```

**Response `201`**
```json
{
  "short_code": "aB3xYz",
  "short_url":  "http://localhost:8080/aB3xYz",
  "original_url": "https://example.com/very/long/path",
  "created_at": 1710000000
}
```

---

### `GET /api/urls` 🔒
List all short URLs, newest first.

**Response `200`**
```json
{
  "count": 2,
  "urls": [
    {
      "short_code": "aB3xYz",
      "short_url": "http://localhost:8080/aB3xYz",
      "original_url": "https://example.com",
      "created_at": 1710000000,
      "visit_count": 5
    }
  ]
}
```

---

### `GET /api/urls/<code>` 🔒
Get metadata for a single short code.

**Response `200`** — same shape as one item from the list above.  
**Response `404`** — code not found.

---

### `DELETE /api/urls/<code>` 🔒
Delete a short URL entry.

**Response `200`**
```json
{ "message": "Deleted 'aB3xYz'" }
```

---

### `GET /<code>`
Redirect to the original URL (HTTP 302).  
Increments `visit_count` on each hit.

---

## Example with `curl`

```bash
# Shorten a URL
curl -X POST http://localhost:8080/api/shorten \
     -H "Authorization: Bearer change-this-secret-key" \
     -H "Content-Type: application/json" \
     -d '{"url": "https://github.com"}'

# Follow the redirect
curl -L http://localhost:8080/aB3xYz

# List all URLs
curl http://localhost:8080/api/urls \
     -H "Authorization: Bearer change-this-secret-key"

# Delete a URL
curl -X DELETE http://localhost:8080/api/urls/aB3xYz \
     -H "Authorization: Bearer change-this-secret-key"
```