ssh2_crontab_manager.php

<?php
use phpseclib3\Net\SSH2;

Class Ssh2_crontab_manager {
    private $connection;
    private $path;
    private $handle;
    private $cron_file;

    public function __construct($host = null, $port = null, $username = null, $password = null)
    {
        $path_length = strrpos(__FILE__, "/");
        $this->path = substr(__FILE__, 0, $path_length) . '/';
        $this->handle = 'crontab.txt';
        $this->cron_file = "{$this->path}{$this->handle}";

        try {
            if (is_null($host) || is_null($port) || is_null($username) || is_null($password)) {
                throw new Exception("Please specify the host, port, username, and password!");
            }

            $this->connection = new SSH2($host, $port);
            if (!$this->connection->login($username, $password)) {
                throw new Exception("Could not authenticate '{$username}' using password: '{$password}'.");
            }
        } catch (Exception $e) {
            $this->error_message($e->getMessage());
        }
    }

    public function exec()
    {
        $argument_count = func_num_args();

        try {
            if (!$argument_count) {
                throw new Exception("There is nothing to execute, no arguments specified.");
            }

            $arguments = func_get_args();
            $command_string = ($argument_count > 1) ? implode(" && ", $arguments) : $arguments[0];
            $stream = $this->connection->exec($command_string);

            if (!$stream) {
                throw new Exception("Unable to execute the specified commands: <br />{$command_string}");
            }
        } catch (Exception $e) {
            $this->error_message($e->getMessage());
        }

        return $this;
    }

    public function write_to_file($path=NULL, $handle=NULL)
    {
        if (! $this->crontab_file_exists())
        {    
            $this->handle = (is_null($handle)) ? $this->handle : $handle;
            $this->path   = (is_null($path))   ? $this->path   : $path;
            $this->cron_file = "{$this->path}{$this->handle}";
            $init_cron = "crontab -l > {$this->cron_file} && [ -f {$this->cron_file} ] || > {$this->cron_file}";

            $this->exec($init_cron);
        }

        return $this;
    }

    public function remove_file()
    {
        if ($this->crontab_file_exists()) $this->exec("rm {$this->cron_file}");

        return $this;
    }

    public function append_cronjob($cron_jobs=NULL)
    {
        if (is_null($cron_jobs)) $this->error_message("Nothing to append! Please specify a cron job or an array of cron jobs.");

        $append_cronfile = "echo '";        

        $append_cronfile .= (is_array($cron_jobs)) ? implode("\\n", $cron_jobs) : $cron_jobs;

        $append_cronfile .= "' >> {$this->cron_file}";

        $install_cron = "crontab {$this->cron_file}";

        $this->write_to_file()->exec($append_cronfile, $install_cron)->remove_file();

        return $this;
    }

    public function remove_cronjob($cron_jobs=NULL)
    {
        if (is_null($cron_jobs)) $this->error_message("Nothing to remove! Please specify a cron job or an array of cron jobs.");

        $this->write_to_file();

        $cron_array = file($this->cron_file, FILE_IGNORE_NEW_LINES);

        if (empty($cron_array)) $this->error_message("Nothing to remove! The cronTab is already empty.");

        $original_count = count($cron_array);

        if (is_array($cron_jobs))
        {
            foreach ($cron_jobs as $cron_regex) $cron_array = preg_grep($cron_regex, $cron_array, PREG_GREP_INVERT);
        }
        else
        {
            $cron_array = preg_grep($cron_jobs, $cron_array, PREG_GREP_INVERT);
        }    

        return ($original_count === count($cron_array)) ? $this->remove_file() : $this->remove_crontab()->append_cronjob($cron_array);
    }

    public function remove_crontab()
    {
        $this->exec("crontab -r")->remove_file();

        return $this;
    }

    private function crontab_file_exists()
    {
        return file_exists($this->cron_file);
    }

    private function error_message($error)
    {
        die("<pre style='color:#EE2711'>ERROR: {$error}</pre>");
    }
}
?>