Add result handler to run command

[wagnert]

Hi,

first i want to say, thanks for that awesome piece of code 👍

We've the requirement, that we want to execute a remote command by invoking the run() method and need to have access to the result.

<?php

return array(

    'hosts' => array(
        'jenkins' => '127.0.0.1',
    ),

    'auth' => array(
        'username' => 'root',
        'password' => NULL,
        'pubkeyfile' => '/home/user/.ssh/id_rsa.pub',
        'privkeyfile' => '/home/user/.ssh/id_rsa',
        'passphrase' => NULL,
    ),

    'tasks' => array(
        'download_test' => function($s) {

            $local = '';
            if (is_file('/tmp/test_encoded.php')) {
                $local = md5_file('/tmp/test_encoded.php');
            }

            $remote = '';
            $resultHandler = function ($resultDio) use (&$remote) {
                $result = explode('  ', $resultDio);
                $remote = array_shift($result);
            };

            $s->run('md5sum test_encoded.php', false, $resultHandler);

            if ($local === $remote) {
                error_log(sprintf('Hashes ARE equal %s/%s', $local, $remote));
            } else {
                error_log(sprintf('Hashes are NOT equal %s/%s', $local, $remote));
                $s->scp()->get('test_encoded.php', '/tmp/test_encoded.php');
            }
        }
    ),
);

The pull request added a third parameter that allows you to specify a closure that can be used to access the command's result. Actually i think there is no possibility to do this, right?