predis/examples/ServerSideScripting.php

<?php

require 'SharedConfigurations.php';

// Additionally to the EVAL command defined in the current development profile, the new
// Predis\Commands\ScriptedCommand base class can be used to build an higher abstraction
// for our "scripted" commands so that they will appear just like any other command on
// the client-side. This is a quick example used to implement INCREX.

use Predis\Commands\ScriptedCommand;

class IncrementExistingKey extends ScriptedCommand {
    protected function keysCount() {
        return 1;
    }

    public function getScript() {
        return
<<<LUA
    if redis('exists', KEYS[1]) == 1 then
        return redis('incr', KEYS[1])
    end
LUA;
    }
}

$client = new Predis\Client($single_server, 'dev');
$client->getProfile()->defineCommand('increx', 'IncrementExistingKey');

$client->set('foo', 10);
var_dump($client->increx('foo'));       // int(11)
var_dump($client->increx('bar'));       // NULL