TTL - Time To Live

Immutable Value Object Time To Live for cache.

Requirements

• PHP 8.1 or higher.

Installation

The package could be installed with Composer:

    composer require elephant-php/vo-ttl

Configuration

Abstract example for your cache

/** @var \Psr\SimpleCache\CacheInterface $psrCache */
$cache = new Cache();

Ttl object

Ttl is a simple immutable value object that represents cache time-to-live (TTL) in seconds. It eliminates magic numbers (like 60 * 60 or 3600), improves readability, and provides convenient factory methods.

Below are examples on how to use it.

If you're using PSR-16 cache adapter directly:

• TTL must be an integer number of seconds or null for infinite lifetime.
• Always use ->toSeconds() when using Ttl object.

use Yiisoft\Cache\Ttl;

$cache = new Cache();

$cache->set('key1', 'value1', Ttl::seconds(30)->toSeconds()); // 30 seconds
$cache->set('key2', 'value2', Ttl::minutes(15)->toSeconds()); // 15 minutes
$cache->set('key3', 'value3', Ttl::hours(2)->toSeconds());    // 2 hours
$cache->set('key4', 'value4', Ttl::days(1)->toSeconds());     // 1 day

// Complex durations
$ttl = Ttl::create(sec: 30, min: 10, hour: 1); // 1 hour 10 minutes 30 seconds
$cache->set('key', 'value', $ttl->toSeconds());

// Infinity / no expiration
$cache->set('key6', 'value6', Ttl::forever()); // shorthand for null
$cache->set('key7', 'value7', Ttl::from(null));

Creating and Normalizing TTL

The Ttl::from() method normalizes various TTL representations (Ttl, DateInterval, int, string, or null) into a Ttl object.

$ttl = Ttl::from(new DateInterval('PT45M')); // 45 minutes
$ttl = Ttl::from(10); // 10 seconds
$ttl = Ttl::from('12'); // 12 seconds
$ttl = Ttl::from(null); // Infinity / no expiration
$ttl = Ttl::from(Ttl::seconds(500));

$ttl = Ttl::create(sec: 30, min: 15);

// From DateInterval
$ttl = Ttl::fromInterval(new DateInterval('PT45M'));
$cache->set('key', 'value', $ttl->toSeconds());

// Ttl::forever() is just a shorthand for `null` TTL (no expiration)
$cache->set('key', 'value', Ttl::forever()->toSeconds());
// or
$cache->set('key', 'value', Ttl::from(null)->toSeconds());

When using Ttl with Yii cache wrapper:

• You can pass a Ttl object in the constructor as the default value.
• You can pass it to methods like getOrSet() which expect integer number of seconds or null.

use Yiisoft\Cache\Cache;
use Your\Cache\ArrayCache;
use Yiisoft\Cache\Ttl;

$cache = new Cache(new ArrayCache(), Ttl::minutes(5)); // default TTL
$cache->getOrSet('key', 'value'); // // Uses default TTL

// Custom TTL
$cache->getOrSet('key2', fn() => 'value2', Ttl::seconds(30)->toSeconds());
$cache->getOrSet('key3', fn() => 'value3', Ttl::forever()->toSeconds()); // No expiration

Additional Features

Checking Infinite TTL:

Use isForever() to check if a TTL represents "forever" (i.e., no expiration). It returns true when the TTL value is null.

if (Ttl::from(null)->isForever()) {
    // No expiration
}

Accessing TTL Value

Use toSeconds() to get the TTL in seconds (int) or null for "forever". The public $value property can be accessed directly (e.g., Ttl::seconds(30)->value), but toSeconds() is preferred for clarity.

$ttl = Ttl::seconds(60);
$seconds = $ttl->toSeconds(); // Returns 60
$seconds = $ttl->value; // Also 60

Invalid TTL values

$ttl = Ttl::from('abc'); // Converts to 0 (expired)
$ttl = Ttl::from(1.5);   // TypeError: invalid TTL type

License

MIT License

Please see LICENSE for more information.