Home/ Questions/Q 6130091
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-23T16:49:04+00:00

Is there a regexp to check if a string is a valid php regexp

  • 0

Is there a regexp to check if a string is a valid php regexp ?

In the back office of my application, the administrator define the data type and he can define a pattern as a regexp. For example /^[A-Z][a-zA-Z]+[a-z]$/ and in the front office, i use this pattern for validate user entries.
In my code i use the PHP preg_match function 

preg_match($pattern, $user_entries);

the first argument must be a valid PHP regexp, how can i be sure that $pattern is a valid regexp since it a user entrie in my back office.

Any idea ?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    Execute it and catch any warnings.

    $track_errors = ini_get('track_errors');
ini_set('track_errors', 'on');
$php_errormsg = '';
@preg_match($regex, 'dummy');
$error = $php_errormsg;
ini_set('track_errors', $track_errors);
if($error) {
    // do something. $error contains the PHP warning thrown by the regex
}

    If you just want to know if the regex fails or not you can simply use preg_match($regex, 'dummy') === false – that won’t give you an error message though.

    • 0