APCu Cache

APCu (Alternative PHP Cache - User) provides fast in-memory caching for PHP applications.

APCu Cache Methods

Basic Usage

use Miko\Cache\ApcuCache;

$cache = new ApcuCache('myapp_');  // Prefix for keys

// Store value (TTL in seconds)
$cache->put('user:1', $userData, 3600);  // 1 hour

// Get value
$user = $cache->get('user:1');

// Get with default
$user = $cache->get('user:1', null);

// Check existence
if ($cache->has('user:1')) {
    // Key exists
}

// Remove
$cache->forget('user:1');

// Clear all
$cache->flush();

Remember Pattern

Get from cache or compute and store:

// If cached, return cached value
// If not, execute callback, cache result, and return
$user = $cache->remember('user:1', function() {
    return User::find(1);
}, 3600);

// With complex computation
$stats = $cache->remember('dashboard:stats', function() {
    return [
        'users' => User::count(),
        'orders' => Order::count(),
        'revenue' => Order::sum('TotalAmount')
    ];
}, 300);  // 5 minutes

Increment / Decrement

// Initialize counter
$cache->put('visitors', 0, 86400);

// Increment
$cache->increment('visitors');
$cache->increment('visitors', 5);  // Increment by 5

// Decrement
$cache->decrement('stock:123');
$cache->decrement('stock:123', 2);  // Decrement by 2

// Get current value
$count = $cache->get('visitors');

Tags Support

Group related cache entries:

// Store with tags
$cache->putWithTags('user:1', $userData, 3600, ['users', 'user_1']);
$cache->putWithTags('user:1:orders', $orders, 3600, ['users', 'user_1', 'orders']);

// Invalidate by tag
$cache->forgetByTag('user_1');  // Removes all user_1 related cache

// Invalidate all users
$cache->forgetByTag('users');

Cache Statistics

$stats = $cache->getStats();

// Returns:
// [
//     'hits' => 15000,
//     'misses' => 500,
//     'hit_rate' => 96.77,
//     'memory_used' => 52428800,
//     'memory_available' => 134217728,
//     'entries' => 1250
// ]

echo "Hit rate: " . $stats['hit_rate'] . "%";
echo "Memory: " . round($stats['memory_used'] / 1024 / 1024, 2) . " MB";

Practical Examples

User Session Cache

class SessionCache
{
    private ApcuCache $cache;
    
    public function __construct()
    {
        $this->cache = new ApcuCache('session_');
    }
    
    public function getUser(int $userId): ?User
    {
        return $this->cache->remember("user:$userId", function() use ($userId) {
            return User::with('roles', 'permissions')->find($userId);
        }, 1800);  // 30 minutes
    }
    
    public function invalidateUser(int $userId): void
    {
        $this->cache->forget("user:$userId");
    }
}

API Rate Limiting

class RateLimiter
{
    private ApcuCache $cache;
    
    public function __construct()
    {
        $this->cache = new ApcuCache('rate_');
    }
    
    public function attempt(string $key, int $maxAttempts, int $decaySeconds): bool
    {
        $attempts = $this->cache->get($key, 0);
        
        if ($attempts >= $maxAttempts) {
            return false;
        }
        
        if ($attempts === 0) {
            $this->cache->put($key, 1, $decaySeconds);
        } else {
            $this->cache->increment($key);
        }
        
        return true;
    }
    
    public function remaining(string $key, int $maxAttempts): int
    {
        return max(0, $maxAttempts - $this->cache->get($key, 0));
    }
}

// Usage
$limiter = new RateLimiter();
$ip = $_SERVER['REMOTE_ADDR'];

if (!$limiter->attempt("api:$ip", 100, 60)) {
    http_response_code(429);
    die('Rate limit exceeded');
}

Configuration Cache

class ConfigCache
{
    private ApcuCache $cache;
    
    public function __construct()
    {
        $this->cache = new ApcuCache('config_');
    }
    
    public function get(string $key, $default = null)
    {
        return $this->cache->remember("config:$key", function() use ($key, $default) {
            $setting = Setting::where('Key', $key)->first();
            return $setting ? $setting->Value : $default;
        }, 3600);
    }
    
    public function set(string $key, $value): void
    {
        Setting::updateOrCreate(['Key' => $key], ['Value' => $value]);
        $this->cache->forget("config:$key");
    }
    
    public function clearAll(): void
    {
        $this->cache->flush();
    }
}

Requirements

APCu must be installed and enabled:

; php.ini
extension=apcu
apc.enabled=1
apc.shm_size=128M
apc.ttl=7200

Check if available:

if (!extension_loaded('apcu') || !apcu_enabled()) {
    throw new Exception('APCu is not available');
}

Best Practices