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Device Fingerprinting

Overview

Laravel Devices supports device fingerprinting through two popular libraries: FingerprintJS (default) and ClientJS. This feature helps identify devices across sessions using browser and device characteristics.

Fingerprinting Flow

sequenceDiagram
    participant C as Client Browser
    participant FT as FingerprintTracker
    participant I as Injector
    participant DM as DeviceManager
    participant DB as Database

    C->>FT: HTTP Request
    
    FT->>DM: Check if fingerprinted
    
    alt Not Fingerprinted
        FT->>I: Get Injector for Library
        I->>C: Inject Fingerprint Script
        
        Note over C: Execute Fingerprint Script
        
        C->>C: Generate Fingerprint
        C->>FT: Next Request with Fingerprint
        
        alt Using Headers
            C->>FT: X-Device-Fingerprint Header
        else Using Cookies
            C->>FT: Fingerprint Cookie
        end
        
        FT->>DM: Store Fingerprint
        DM->>DB: Update Device Record
    else Already Fingerprinted
        FT->>C: Continue Request
    end
Loading

Basic Configuration

Configuration File

// config/devices.php
return [
    'fingerprinting_enabled' => true,
    'client_fingerprint_transport' => 'cookie', // or 'header'
    'client_fingerprint_key' => 'csf',
];

Middleware Registration

To automatically try to fingerprint devices, add the FingerprintTracker middleware to the global middleware stack. This middleware checks if the device is fingerprinted and injects the fingerprinting script if needed. Must be added after the DeviceTracker middleware.

// app/Http/Kernel.php
protected $middleware = [
    \Ninja\DeviceTracker\Http\Middleware\DeviceTracker::class,
    // ...
    \Ninja\DeviceTracker\Modules\Fingerprinting\Http\Middleware\FingerprintTracker::class,
];

FingerprintJS Integration (Default)

Basic Setup

// config/devices.php
return [
    'fingerprinting_enabled' => true,
    'fingerprint_client_library' => \Ninja\DeviceTracker\Modules\Fingerprinting\Injector\Enums\Library::FingerprintJS,
];

Generated Script

// Automatically injected by FingerprintJSInjector
const fpPromise = import('https://openfpcdn.io/fingerprintjs/v4')
    .then(FingerprintJS => FingerprintJS.load())

fpPromise
    .then(fp => fp.get())
    .then(result => {
        const fingerprint = result.visitorId;
        
        // Store fingerprint based on configuration
        if (window.DeviceTracker.config.transport.type === 'header') {
            // Will be sent in next request
            window.DeviceTracker.config.current = fingerprint;
        } else {
            // Set as cookie
            document.cookie = `${window.DeviceTracker.config.transport.key}=${fingerprint}; expires=Fri, 31 Dec 9999 23:59:59 GMT; path=/`;
        }
    });

Important Notes About FingerprintJS

/**
 * Important notes:
 * 1. FingerprintJS is the default and recommended option
 * 2. Free for development and prototyping
 * 3. Requires paid license for production use
 * 4. Provides more accurate fingerprinting
 * 5. Regular updates and maintenance
 */

ClientJS Integration

Configuration

// config/devices.php
return [
    'fingerprinting_enabled' => true,
    'fingerprint_client_library' => \Ninja\DeviceTracker\Modules\Fingerprinting\Injector\Enums\Library::ClientJS,
];

Generated Script

// Automatically injected by ClientJSInjector
if (window.DeviceTracker.config.current === null) {
    const client = new ClientJS();
    const fingerprint = client.getFingerprint();
    
    // Store fingerprint based on configuration
    window.DeviceTracker.config.current = fingerprint;
    
    if (window.DeviceTracker.config.transport.type === 'cookie') {
        document.cookie = `${window.DeviceTracker.config.transport.key}=${fingerprint}; expires=Fri, 31 Dec 9999 23:59:59 GMT; path=/`;
    }
}

Important Notes About ClientJS

/**
 * Important notes:
 * 1. Fully open-source alternative
 * 2. Free for all use cases
 * 3. Simpler fingerprinting algorithm
 * 4. Lighter weight
 * 5. Discontinued package. May require manual updates
 */

Fingerprint Transport Methods

Header Transport

// Configuration
'client_fingerprint_transport' => 'header',
'client_fingerprint_key' => 'X-Device-Fingerprint',

// Generated headers in requests
X-Device-Fingerprint: f0a4d8c9e1b3f2a5

Cookie Transport

// Configuration
'client_fingerprint_transport' => 'cookie',
'client_fingerprint_key' => 'device_fingerprint',

// Generated cookie
document.cookie = 'csf=f0a4d8c9e1b3f2a5; path=/';

Custom Implementation

Custom Injector

use Ninja\DeviceTracker\Modules\Fingerprinting\Injector\AbstractInjector;

class CustomInjector extends AbstractInjector
{
    public const LIBRARY_NAME = 'custom';
    public const LIBRARY_URL = 'https://your-custom-library.js';
    
    protected static function script(Device $device): string
    {
        return view('custom-fingerprint-script', [
            'current' => $device->fingerprint,
            'transport' => [
                'type' => config('devices.client_fingerprint_transport'),
                'key' => config('devices.client_fingerprint_key')
            ],
            'library' => [
                'name' => static::LIBRARY_NAME,
                'url' => static::LIBRARY_URL
            ]
        ])->render();
    }
}

Custom Library Registration

use Ninja\DeviceTracker\Modules\Fingerprinting\Injector\Factories\InjectorFactory;

// Register in service provider
public function register(): void
{
    $this->app->bind(Injector::class, function ($app) {
        return InjectorFactory::make(Library::Custom);
    });
}

Working with Fingerprints

Retrieving Fingerprints

// Get current device fingerprint
$fingerprint = DeviceManager::current()->fingerprint;

// Find device by fingerprint
$device = Device::byFingerprint($fingerprint);

// Check if device is fingerprinted
if (DeviceManager::fingerprinted()) {
    // Device has fingerprint
}

Fingerprint Validation

class FingerprintValidator
{
    public function validate(string $fingerprint): bool
    {
        // Check format
        if (!preg_match('/^[a-f0-9]{32}$/', $fingerprint)) {
            return false;
        }
        
        // Check if fingerprint exists
        $device = Device::byFingerprint($fingerprint);
        if ($device) {
            // Validate device status
            return !$device->hijacked();
        }
        
        return true;
    }
}

Security Considerations

Fingerprint Reliability

// Example fingerprint reliability check
public function isReliableFingerprint(Device $device): bool
{
    // Check fingerprint age
    $fingerprintAge = $device->updated_at->diffInDays(now());
    if ($fingerprintAge > 30) {
        return false;
    }
    
    // Check for fingerprint collisions
    $devicesWithSameFingerprint = Device::where('fingerprint', $device->fingerprint)
        ->where('uuid', '!=', $device->uuid)
        ->count();
        
    if ($devicesWithSameFingerprint > 0) {
        return false;
    }
    
    return true;
}

Best Practices

  1. Regular Validation
// Implement regular fingerprint validation
public function validateFingerprints(): void
{
    Device::chunk(100, function ($devices) {
        foreach ($devices as $device) {
            if (!$this->isReliableFingerprint($device)) {
                // Reset fingerprint
                $device->fingerprint = null;
                $device->save();
                
                // Log incident
                Log::warning('Unreliable fingerprint detected', [
                    'device_uuid' => $device->uuid
                ]);
            }
        }
    });
}
  1. Fingerprint Updates
// Handle fingerprint updates
public function updateFingerprint(Device $device, string $newFingerprint): void
{
    // Store old fingerprint
    $oldFingerprint = $device->fingerprint;
    
    // Update fingerprint
    $device->fingerprint = $newFingerprint;
    $device->save();
    
    // Log change
    Log::info('Device fingerprint updated', [
        'device_uuid' => $device->uuid,
        'old_fingerprint' => $oldFingerprint,
        'new_fingerprint' => $newFingerprint
    ]);
}

Next Steps