Cron Parser

Installation

composer require thesis/cron-parser

Basic usage

Matching date

<?php

declare(strict_types=1);

use Thesis\Cron;

$parser = Cron\Parser::standard();
$time = $parser->parse('* * * * *'); 
echo $time->match(new \DateTimeImmutable('2025-01-29 00:00:00')); // true

Getting next date

<?php

declare(strict_types=1);

use Thesis\Cron;

$parser = Cron\Parser::standard();
$time = $parser->parse('* * * * *');
echo $time->tick(new \DateTimeImmutable('2025-01-29 00:00:00')); // 2025-01-29 00:01:00 

Iterating on Thesis\Cron\Time

<?php

declare(strict_types=1);

use Thesis\Cron;

$parser = Cron\Parser::standard();
$time = $parser->parse('* * * * *');

foreach ($time->iterator(new \DateTimeImmutable('2025-01-29 00:00:00'), iterations: 10) as $it) {
    echo $it->format('Y-m-d H:i:s');
}

Configure parser

<?php

declare(strict_types=1);

use Thesis\Cron;

$parser = new Cron\Parser(
    extension: new Cron\StandardParserExtension(),
    replacers: [new Cron\AliasExpressionReplacer(['@secondly' => '* * * * * *'])],
    normalizers: [new Cron\SundayExpressionNormalizer(), new Cron\WeekdayExpressionNormalizer()],
);

$time = $parser->parse('@secondly');

echo $time->match(new \DateTimeImmutable('2025-01-29 00:00:00')); // true
echo $time->match(new \DateTimeImmutable('2025-01-29 00:00:01')); // true
echo $time->match(new \DateTimeImmutable('2025-01-29 00:00:02')); // true

Parser architecture

ExpressionReplacer works with a cron string and is needed to replace the entire string. For example, AliasExpressionReplacer implements this interface and replaces popular expressions like @hourly, @monthly with the corresponding cron expressions. This is the first step in parsing the cron expression.

The next step is normalization, and it is performed using ExpressionNormalizer, which works with an Expression object, which is some intermediate representation of the cron string. At this point, you can replace expressions atomically. For example, WeekdayExpressionNormalizer replaces only the weekdays from expressions like MON, TUE, FRI with numeric ones.

In the last step, called the parsing step, the expression is finally processed and transformed from an Expression object to a Time object. At this stage you can use StandardParserExtension or add your own.