Caching wrapper

wrapper.php

<?php

// This is how we normally get the data.
class ItemRepo
{
    function getItems(string $queryParam1, int $queryParam2) {
        // run the query against the DB.
    }
}


// This is a wrapping version of the repo
class CacheItemRepo extends ItemRepo
{
    private $redis;
    
    public function __construct(Redis $redis)
    {
        $this->redis = $redis;
    }

    function getItems(string $queryParam1, int $queryParam2)
    {
        $key = json_encode([
            'queryParam1' => $queryParam1,
            'queryParam2' => $queryParam2,
        ]);
        $key = sha1($key);

        $keyname = 'itemrepo:cache:' . $key;
        
        $cachedResult = $this->redis->get($keyname);
        
        // Is it in the cache - yes
        if ($cachedResult !== false) {
            // Actually need to conver the result back from a string here.
            return $cachedResult;
        }
        
        // not in the cache, so fetch it from the DB,
        $data = parent::getItems($queryParam1, $queryParam2);
        
        // And store it in the cache for 300 seconds
        $this->redis->setex($keyname, 300, $data);
        
        return $data;
    }
}