Looking for feedback on my PHP filter_var regular expression

win32sux · 09-03-2008, 01:21 PM

I'm a PHP newbie, and even worse when it comes to regular expressions. So basically I'm looking for any feedback about whether I'm doing this right or not. I'm performing a check on some XHTML form input (a person's first name). I decided I only want to allow letters, dashes, and individual spaces. Here's what I've currently got:

PHP Code:



if (filter_var($Name, FILTER_VALIDATE_REGEXP, 
array("options"=>array("regexp"=>"/[^A-Za-z\-][ ]{1}/")))) 
   { 
      // Bad input detected. 
   } 
else 
   { 
      // Input looks good. 
   }

The [^A-Za-z\-][ ]{1} regular expression I put together seems to do what I want (at least in my rudimentary tests), but does it look okay to you? I will add more thorough checking later, right now I just wanna make sure I'm doing this basic checking properly. TIA.

keefaz · 09-03-2008, 02:24 PM

The reg exp looks ok, but the use of filter_var() with a reg exp seems a bit counter productive imho as you are not using the built in filter for filter_var but your own reg exp instead..
Why not use preg_match() ?

PHP Code:



if(preg_match("/[^A-Za-z\-][ ]{1}/", $Name)) {
    // Bad input detected.
} else {
    // Input looks good. 

}

win32sux · 09-03-2008, 03:32 PM

Thanks for the advice, I shall follow it and use preg_match() instead.