Implementing Redis Cache in PHP Using the __call Magic Method

The article introduces a PHP caching solution that uses Redis to meet several goals: sharing the model layer between front‑end and back‑end modules, avoiding wasteful per‑model caching, allowing modules to choose between database and cache reads, eliminating redundant code, and providing an easy‑to‑use interface.

It demonstrates the desired usage pattern where a Book class can be called as (new Book)->getById(100) (original method), (new Book)->getByIdCache(100) (cached call), (new Book)->getByIdClear(100) (clear cache), and (new Book)->getByIdFlush() (flush all related caches).

The implementation relies on PHP's magic method __call(), which is invoked when an undefined method is called. By parsing the method name suffix (Cache, Clear, Flush), the code decides whether to read from Redis, store data, delete a specific cache entry, or flush a set of keys.

Example of a simple Book class with a regular getById($id) method and an overridden __call($name, $arguments) that prints a message for undefined methods.

A singleton Common class provides a Redis connection via Common::redis(), ensuring a single Redis instance throughout the application.

class Book {
    public function __call($name, $arguments) {
        if (strlen($name) < 5) { exit('Method does not exist.'); }
        $method = substr($name, 0, -5);
        $action = substr($name, -5);
        $class = get_class();
        $key = sprintf('%s:%s:', str_replace('\\', '_', $class), $method);
        $key = strtolower($key);
        switch ($action) {
            case 'Cache':
                $key .= md5(json_encode($arguments));
                $data = Common::redis()->get($key);
                if ($data !== false) {
                    $decodeData = json_decode($data, JSON_UNESCAPED_UNICODE);
                    return $decodeData === null ? $data : $decodeData;
                }
                if (!method_exists($this, $method)) { exit('Method does not exist.'); }
                $data = call_user_func_array([$this, $method], $arguments);
                Common::redis()->set($key, json_encode($data), 3600);
                return $data;
            case 'Clear':
                $key .= md5(json_encode($arguments));
                return Common::redis()->del($key);
            case 'Flush':
                $key .= '*';
                $keys = Common::redis()->keys($key);
                return Common::redis()->del($keys);
            default:
                exit('Method does not exist.');
        }
    }
    // other methods
}

class Common {
    private static $redis = null;
    public static function redis() {
        if (self::$redis === null) {
            self::$redis = new \Redis('127.0.0.1');
            self::$redis->connect('redis');
        }
        return self::$redis;
    }
}

By integrating this __call logic into a base model class, developers can centralize caching behavior, reduce coupling, and simplify maintenance across the application.

The full source code and further usage instructions are available on the project's GitHub repository.