preg_match and variables

Stinger51

I've written a password checking function that uses preg_match as :

if (preg_match('/^{[a-z0-9]{5,10}/i',} $pWord))
{
return $pWord; // Good password
}
else
// return error;

This allows me to check for passwords that contain alpha-numerics and are 5 to 10 chars in length. But I wanted to pass the function min and max values instead, as :

if (preg_match('/^{[a-z0-9]{$min,$max}/i',} $pWord))

It seems the function is ignoring these values. Any suggestions?

Also, what is the correct syntax here for allowing special chars, such as "!@#$%" etc.? I tried the following, but it didn't work :

if (preg_match('/^{[a-z0-9!@#$%]{5,10}/i',} $pWord))

Thanks in advance.

bubblenut

You need to either use double quotes or drop out of the single words and concatenate. Single quotes are not parsed to the $min is used as is (a dollar sign, an m, an i and an n) rather than the value contained within it. Also you need a $ at the end otherwise it will not force the match to the end of the string, ie it will match strings even if they are too long.
Use either
preg_match('/^{[0-9a-z]{'.$min.','.$max.'}$/i',} $pWord);
or
preg_match("/^{[0-9a-z]{$min,} $max\$/i", $pWord);
HTH
Bubble

laserlight

It has to do with PHP strings, not the regex.
PHP strings delimited by single quotes are not parsed for variables.
PHP strings delimited by double quotes are parsed for variables.

So you should use:

if (preg_match("/^[a-z0-9]{$min,$max}\$/i", $pWord))

For the special characters:

if (preg_match('/^[a-z0-9\!\@\#\$\%]{' . $min . ',' . $max . '}$/i', $pWord))

In this case I've chosen to use single quoted strings, and concatenate the variables instead.
This is to avoid potential problems when "$" is used.

Stinger51

Thanks folks.

I got this (from both of you) to work :

if ( preg_match('/^{[0-9a-z]{'.$min.','.$max.'}$/i',} $pWord) )

but when I tried this construction :

if ( preg_match("/^{[a-z0-9]{$min,$max}\$/i",} $pWord) )

I got the following PHP (4.3) error :

Parse error: parse error, unexpected ',', expecting '}' in C:\Program Files\Apache . . .

Not sure why this is happening. What am I missing here?