Question

Possible Duplicate:
Validating Crontab Entries w/ PHP

I have search everywhere, and my Regex is poor, so i seek assistance.

I am building a web based CRON tool, and the form can and will only pass the following to the processing script.'0-99' ',' '*' '-' '/'

I wan to validate the input with a simple preg_match in PHP, but cannot seem to come up with the correct regex. Can some one help out?
Also, i will validate each item in the cron i.e. NOT * * * * *
but rather the minutes value, then the hours value etc.. This allows more specific errors to be sent back.

examples of the passed values would be

*
0,10
*/5
1,3,5
1-5

here is a poor attempt just to match digits and the *
/[0-9*]/
Any assistance would be great.

Regards

Answer 1

Let’s see:

$pattern = '/^(?:[1-9]?\d|\*)(?:(?:[\/-][1-9]?\d)|(?:,[1-9]?\d)+)?$/';

This pattern will allow you to match a reasonable subset of valid CRON sentences. It sure does match every single one of your examples. The exact pattern depends on the grammar you define, though.

EDIT
Forgot to mention that regex matching alone won’t cut it. What it can do, is to check whether or not the input is correct in terms of (your simplified) syntax. Other than that you will need to validate the input with regards to semantics (e.g. hours 0-23; days 1-30/1 etc.).