Cache Store

The KeyValueCacheEngine class adds a PSR-16 compatible cache layer on top of any KeyValueStore.

PSR-16 Compliance

This cache implementation follows the PSR-16: Common Interface for Caching Libraries standard, ensuring compatibility with any PSR-16 compatible application.

It allows you to cache results locally and avoid unnecessary calls to the underlying KeyValueStore.

Basic Usage

<?php
use ByJG\AnyDataset\NoSql\Cache\KeyValueCacheEngine; 
use ByJG\AnyDataset\NoSql\Factory;

// Create the KeyValueStore
Factory::registerDriver(\ByJG\AnyDataset\NoSql\AwsS3Driver::class);
$keyValueStore = Factory::getInstance('s3://...');

// Create the Cache Object
$cache = new KeyValueCacheEngine($keyValueStore);

// Store a value with the default TTL
$cache->set('key', 'value');

// Store with a specific TTL (in seconds)
$cache->set('key', 'value', 3600); // 1 hour

// Or with a DateInterval
$cache->set('key', 'value', new \DateInterval('PT1H')); // 1 hour

// Retrieve a value (returns null if not found or expired)
$value = $cache->get('key');

// Retrieve with a default value if not found
$value = $cache->get('key', 'default value');

// Check if a key exists and is not expired
if ($cache->has('key')) {
    // Key exists and is not expired
}

// Delete a key
$cache->delete('key');

Logging

You can provide a PSR-3 compatible logger to the cache engine:

<?php
use ByJG\AnyDataset\NoSql\Cache\KeyValueCacheEngine;
use Psr\Log\LoggerInterface;

// Create your PSR-3 compatible logger
$logger = new YourPsrLogger();

// Pass it to the cache engine
$cache = new KeyValueCacheEngine($keyValueStore, $logger);

// Now operations will be logged
$cache->set('key', 'value'); // Will log the operation
$value = $cache->get('key'); // Will log the retrieval

Implementation Details

The KeyValueCacheEngine stores values in the underlying KeyValueStore with the following structure:

• Values are stored with the cache key as provided
• TTL values are stored with the .ttl suffix appended to the key
• Values are serialized before storage
• TTL is stored as a Unix timestamp

Limitation

The clear() method to clear all cache entries is not implemented (returns false) as it would require listing all keys in the KeyValueStore, which may not be efficient or supported by all backends.

Available Methods

Method	Description
get(string $key, mixed $default = null): mixed	Fetches a value from the cache
set(string $key, mixed $value, null|int|\DateInterval $ttl = null): bool	Stores a value in the cache
delete(string $key): bool	Removes a value from the cache
has(string $key): bool	Determines if a cache key exists and is not expired
clear(): bool	Not implemented, always returns false
isAvailable(): bool	Checks if the cache is available, always returns true