Easy crontab manager for PHP. Uses shell_exec!

Crontab.class.php

<?php

class Crontab {

  /*

  (c) Gustav Genberg 2017

  This script uses PHP shell_exec! Make sure it is enabled before using!
  Also make sure that the user running this script (usually www-data) have access to the crontab command!

  Note that this script should be working fine as it is (Apache2)

  Crontab usage:  crontab [-u user] file
                  crontab [ -u user ] [ -i ] { -e | -l | -r }
                          (default operation is replace, per 1003.2)
                  -e      (edit user's crontab)
                  -l      (list user's crontab)
                  -r      (delete user's crontab)
                  -i      (prompt before deleting user's crontab)



  PHP-Crontab usage:  Crontab::[ Read ] [ Set ] [ Add ] [ Remove ] [ Check ]

                      Read      (Returns array of ALL [usually www-data] 's cronjobs)
                      Set       (Takes array with cronjobs and REPLACES the existing cronjobs)
                      Add       (Takes string formatted as a cronjob and adds it)
                      Remove    (Takes string and will remove all cronjobs that matches the provided string [case-sensitive])
                      Check     (Returns boolean based on cronjob existance)

  Examples:

    Crontab::Add('0 0 * * 6 sh /backup/run.sh');

    Crontab::Remove('0 0 * * 6 sh /backup/run.sh');
    // OR
    Crontab::Remove('/backup/run.sh');

    Crontab::Check('/backup/run.sh'); // false

  */

  public static function Read () {

    $Jobs = shell_exec('crontab -l');

    $Jobs = explode("\n", $Jobs);

    array_pop($Jobs);

    return $Jobs;

  }

  public static function Set ($Jobs) {

    $file = fopen('/tmp/php-crontab.tmp', 'w');

    for($i = 0; $i < count($Jobs); $i++) {

      fwrite($file, $Jobs[$i] . "\n");

    }

    fclose($file);

    shell_exec('crontab /tmp/php-crontab.tmp');

    unlink('/tmp/php-crontab.tmp');

  }

  public static function Add ($Job) {

    $Jobs = Crontab::Read();

    if(Crontab::Check($Job)) return;

    array_push($Jobs, $Job);

    Crontab::Set($Jobs);

  }

  public static function Remove ($Job) {

    $Jobs = Crontab::Read();

    $UpdatedJobs = [];

    for($i = 0; $i < count($Jobs); $i++) {

      if(strpos($Jobs[$i], $Job) !== false) continue;

      array_push($UpdatedJobs, $Jobs[$i]);

    }

    Crontab::Set($UpdatedJobs);

  }

  public static function Check ($Job) {

    $Jobs = Crontab::Read();

    for($i = 0; $i < count($Jobs); $i++) {

      if(strpos($Jobs[$i], $Job) !== false) return true;

    }

    return false;

  }

}

?>