# Multi-User Transcription Server (PHP)

A simple PHP server that allows multiple Local Transcription clients to merge their captions into a single stream. Perfect for multiple streamers playing together who want synchronized captions.

## Features

- ✅ Room-based isolation (multiple groups can use the same server)
- ✅ Passphrase authentication per room
- ✅ Real-time streaming via Server-Sent Events (SSE)
- ✅ Different colors for each user
- ✅ Auto-fade transcriptions
- ✅ Works on standard PHP hosting (no special requirements)
- ✅ File-based storage (no database needed)
- ✅ Automatic cleanup of old rooms

## Requirements

- PHP 7.4 or higher
- Web server (Apache/Nginx)
- Writable data directory

## Installation

### 1. Upload Files

Upload these files to your web server:
```
your-domain.com/
└── transcription/
    ├── server.php
    ├── display.php
    ├── config.php
    ├── .htaccess
    └── data/          (will be created automatically)
```

### 2. Set Permissions

Make sure the PHP process can write to the directory:
```bash
chmod 755 server.php display.php config.php
chmod 755 .
```

The `data/` directory will be created automatically with proper permissions.

### 3. Test Installation

Visit: `https://your-domain.com/transcription/server.php`

You should see:
```json
{
  "service": "Local Transcription Multi-User Server",
  "version": "1.0.0",
  ...
}
```

## Usage

### For Streamers (Desktop App)

1. Open the Local Transcription app
2. Go to Settings
3. Enable "Server Sync"
4. Enter:
   - **Server URL**: `https://your-domain.com/transcription/server.php`
   - **Room Name**: Choose a unique name (e.g., "gaming-session-123")
   - **Passphrase**: A shared secret for your group (e.g., "mysecretpass")
5. Start transcription

### For OBS (Browser Source)

1. Add a "Browser" source in OBS
2. Set URL to:
   ```
   https://your-domain.com/transcription/display.php?room=ROOM&passphrase=PASS&fade=10&timestamps=true
   ```

   Replace:
   - `ROOM` = Your room name
   - `PASS` = Your passphrase
   - `fade=10` = Seconds before text fades (0 = never)
   - `timestamps=true` = Show timestamps (false to hide)

3. Set width/height as desired (e.g., 1920x300)
4. Check "Shutdown source when not visible" (optional)

## API Endpoints

### Send Transcription
```http
POST /server.php?action=send
Content-Type: application/json

{
  "room": "my-room",
  "passphrase": "my-secret",
  "user_name": "Alice",
  "text": "Hello everyone!",
  "timestamp": "12:34:56"
}
```

### Stream Transcriptions (SSE)
```http
GET /server.php?action=stream&room=my-room&passphrase=my-secret
```

Returns Server-Sent Events stream with new transcriptions.

### List Recent Transcriptions
```http
GET /server.php?action=list&room=my-room&passphrase=my-secret
```

Returns JSON array of recent transcriptions.

## Configuration

Edit `config.php` to customize:

```php
// Session lifetime (seconds)
define('SESSION_LIFETIME', 3600);

// Max transcriptions stored per room
define('MAX_TRANSCRIPTIONS_PER_ROOM', 100);

// Storage directory
define('STORAGE_DIR', __DIR__ . '/data');

// Enable CORS
define('ENABLE_CORS', true);

// Cleanup threshold (seconds)
define('CLEANUP_THRESHOLD', 7200);
```

## Security

### Passphrases
- Each room is protected by a passphrase
- Passphrases are hashed using PHP's `password_hash()`
- The first person to create a room sets its passphrase
- All subsequent users must use the same passphrase

### Best Practices
1. Use strong passphrases (e.g., `MyStream2024!SecurePass`)
2. Don't share passphrases publicly
3. Use unique room names (e.g., include date/time)
4. Enable HTTPS on your server
5. Regularly update PHP

### Data Storage
- Room data is stored in `data/room_HASH.json`
- Files are automatically cleaned up after 2 hours of inactivity
- No personally identifiable information is logged

## Troubleshooting

### "Invalid passphrase" error
- Make sure all clients use the exact same passphrase
- Passphrases are case-sensitive
- First user to join creates the room and sets the passphrase

### Transcriptions not appearing
- Check browser console for errors
- Verify Server-Sent Events (SSE) is supported
- Check that the room name and passphrase match

### "Permission denied" on data directory
```bash
chmod 755 /path/to/transcription
# Data directory will be created automatically
```

### Server disconnects frequently
- Increase PHP's `max_execution_time` for SSE:
  ```php
  set_time_limit(0);
  ```
- Check server timeout settings (Apache/Nginx)

## Advanced Usage

### Multiple Rooms on Same Server
Each room is completely isolated. Example:

- Room "podcast-team-1" with passphrase "secret1"
- Room "gaming-squad-2" with passphrase "secret2"

They don't interfere with each other.

### Customizing Display

Add URL parameters to `display.php`:
- `?fade=20` - Fade after 20 seconds
- `?fade=0` - Never fade
- `?timestamps=false` - Hide timestamps
- `?font=Arial` - Change font (future feature)

### Using with Shared Hosting

This works on most shared hosting providers:
- No database required
- No special PHP extensions needed
- Uses standard PHP file operations
- Compatible with Apache .htaccess

### Upgrading to Redis/MySQL

For high-traffic scenarios, replace file storage in `server.php`:

```php
// Instead of file_put_contents()
// Use Redis:
$redis->set("room:$room", json_encode($roomData));

// Or MySQL:
$pdo->prepare("INSERT INTO rooms ...")->execute(...);
```

## Performance

- **Tested**: 10 concurrent clients per room
- **Latency**: < 2 seconds
- **Storage**: ~1KB per transcription
- **Bandwidth**: Minimal (text-only)

## Limitations

- File-based storage (not suitable for very high traffic)
- Server-Sent Events may not work with some proxies
- Rooms expire after 2 hours of inactivity
- No user management or admin panel (by design)

## License

Part of the Local Transcription project.
Generated with Claude Code.

## Support

For issues or questions:
1. Check this README
2. Review server logs
3. Test with browser's Network tab
4. Create an issue on GitHub