regex for allowed characters in a form field

[DogTags]

Hi All

I'm trying to come up with a regex for validating allowed characters in a form field.

The idea is that if any characters other than those in the approved list are entered in the field, then the form will return an error and message.

I don't know regex from a hole in the ground. So, I'm hoping that someone might have some good ideas about this.

Here is the list of approved characters:

$ALLOWED_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvw xyz&#!(-)'+/=?:@\""

Yes, the double quote is also allowed and it is escaped near the end.

What would be a good regex to test for these allowed chars?

Many thanks

[idx]

Something like the following should work:

PHP Code:

<?php
  $input = 'FOO' .  "\07"; //FOO plus a BEL 
//  $input = 'FOO';  //uncomment for a valid response.

//  print_r($input);

  if (preg_match('/[^A-Za-z0-9&#\!\(\)-+\/=\?:@\'\"]/', $input)) {
     echo 'Error!';
  }
  else {
     echo 'Input Validated';
  }

?>

Notice the carot in front of A-Z. That negates the statement, so if preg_match is successful that means something other than the allowable characters was matched.

You may also want to look at the Validate pear class. Looks like a consistent interface to validate input.

-r