Creating a "Next Run Time" date from a cronjob-like syntax

Question

In an app I'm creating a user is given the possibility to schedule a repeating task. Simply the values for generating the interval schema are:

Minute: [0-59, 90 (each minute)]
Hour: [0-23, 90 (each hour)]
Day of month: [1-31, 90 (each day of month), 91 (last day of month)]
Month: [1-12, 90 (each month)]

So, for example I've got this format: 10 - 2 - 90 - 90 which translates to 2015-07-16 2:10. The method determining the next run time date is able to present me this date. But, I'm looking for the efficient way to check if the next run time date has already passed (easy part) but then generate the first next run time date again. In this case it would be 2015-07-17 2:10.

I've found out that our brain is easily up to the task but I'm unsure which logical steps to follow to determine this in the most efficient way (without writing out all posibilities that is).

Any suggestions?

Answer 1

It is working fine. I am using PHP Cron Parser. It has everything that we needed.

Or else, you could use Cron Expression easier and more efficient. Some reference answers are already here and here in Stack Overflow.

For Cron Expression, you could use:

$cron = Cron\CronExpression::factory('@daily');
$cron->isDue();
echo $cron->getNextRunDate()->format('Y-m-d H:i:s');//this give next run date.
//echo $cron->getPreviousRunDate()->format('Y-m-d H:i:s');//this give previous run date.

And this is exactly the same what you have and Cron Expression also have,

All what you need to do is, just use PHP Cron Expression. Hope this helps.

Answer 2

This is nearly Cron syntax, so why creating something own which does exactly the same job?

It should be pretty easy to switch to a valid cron syntax and use a simple library for parsing, etc.

An example would be https://github.com/mtdowling/cron-expression where you could get the next run date for free:

$cron->getNextRunDate()->format('Y-m-d H:i:s');

You would also have the possibility to use values like 0/15 to run every 15 minutes, etc. Another benefit is, that cron syntax is common knowledge which prevents misinterpretation of the format.