Question

I’m obviously not using filter_var() correctly. I need to check that the user has entered a valid date, in the form “dd/mm/yyyy”.

This simply returns whatever I passed as a date, while I expected it to return either the date or 0/null/FALSE in case the input string doesn’t look like a date:

$myregex = "/\d{2}\/\d{2}\/\d{4}/";
print filter_var("bad 01/02/2012 bad",FILTER_VALIDATE_REGEXP,array("options"=>array("regexp"=> $myregex)));

If someone else uses this function to check dates, what am I doing wrong? Should I use another function to validate form fields?

Thank you.

Answer 1

$myregex = '~^\d{2}/\d{2}/\d{4}$~';

The regex matched because you just require that pattern anywhere in the string. What you want is only that pattern and nothing else. So add ^ and $.

Note that this still doesn’t mean the value is a valid date. 99/99/9999 will pass that test. I’d use:

if (!DateTime::createFromFormat('d/m/Y', $string))