gistfile1.php

<?php

use Predis\Async\Client as PredisClient;

function save(PredisClient $redis)
{
    $deferred = new Deferred();
    $saddDeferred = new Deferred();

    // let's start a transaction
    $tx = $redis->multiExec();
    
    // transaction has began
    
    // increment the job-counter key
    $tx->incr('job-counter');
    $tx->execute(function ($replies, $redis) use ($job, $deferred, $saddDeferred) {

        // we execute the transaction here 
        
        // the result of the commands previously executed are in the $reply array
        // here, $replies[0] contains the Id
        $hashId = 'job-' . $replies[0];

        $deferred->then(function() use ($redis, $hashId, $saddDeferred) {

            // once the promised is resolved, execute SADD as second command to store the hash key in a set
            $redis->sadd('jobs', $hashId, function() use ($hashId, $saddDeferred) {
                // once the second command is executed, resolve the promise
                $saddDeferred->resolve($hashId);
            });

            return $saddDeferred->promise();
        });

        // lets build the argument of the HMSET command that is used to store hashes :
        // HMSET key field1 value1 field2 value2
        $hash = array_merge(array($hashId), array('key' => 'value'), array(function() use ($deferred, $hashId){
            // once the command has been executed, lets resolve the promise
            $deferred->resolve($hashId);
        }));

        // execute the command
        call_user_func_array(array($redis, 'hmset'), $hash);
    });

    return $saddDeferred->promise();
}