[support] getting the underscore to be unusable in user names

[Neil: esl-lounge.com]

Could someone help me with the regex syntax for disallowing underscores:

/**
 * Verify the syntax of the given name.
 */
function user_validate_name($name) {
  if (!strlen($name)) return t('You must enter a username.');
  if (substr($name, 0, 1) == ' ') return t('The username cannot begin with a 
space.');
  if (substr($name, -1) == ' ') return t('The username cannot end with a 
space.');
  if (strpos($name, '  ') !== FALSE) return t('The username cannot contain 
multiple spaces in a row.');
  if (ereg("[^\x80-\xF7 [:alnum:]@_.-]", $name)) return t('The username 
contains an illegal character.');
  if (preg_match('/[\x{80}-\x{A0}'.          // Non-printable ISO-8859-1 + 
NBSP
                   '\x{AD}'.                 // Soft-hyphen
                   '\x{2000}-\x{200F}'.      // Various space characters
                   '\x{2028}-\x{202F}'.      // Bidirectional text overrides
                   '\x{205F}-\x{206F}'.      // Various text hinting 
characters
                   '\x{FEFF}'.               // Byte order mark
                   '\x{FF01}-\x{FF60}'.      // Full-width latin
                   '\x{FFF9}-\x{FFFD}'.      // Replacement characters
                   '\x{0}]/u',               // NULL byte
                   $name)) {
    return t('The username contains an illegal character.');
  }
  if (strpos($name, '@') !== FALSE && 
!eregi('@([0-9a-z](-?[0-9a-z])*.)+[a-z]{2}([zmuvtg]|fo|me)?$', $name)) 
return t('The username is not a valid authentication ID.');
  if (strlen($name) > USERNAME_MAX_LENGTH) return t('The username %name is 
too long: it must be %max characters or less.', array('%name' => $name, 
'%max' => USERNAME_MAX_LENGTH));
}

what do all the Xxxxx characters signify? Also this line:

  if (ereg("[^\x80-\xF7 [:alnum:]@_.-]", $name)) return t('The username 
contains an illegal character.');

seems to be disallowing @, underscore, period and hyphen...or is it allowing 
them? Regular expressions were never my forte!

Neil

----- Original Message ----- 
From: "Cog Rusty" <cog.rusty at gmail.com>
To: <support at drupal.org>
Sent: Wednesday, August 01, 2007 6:25 PM
Subject: Re: [support] getting the underscore to be unusable in user names


> Probably. I don't know if underscores would accept escaping with a
> backslash (\_) in that field. You could try it.
>
>
>
> On 8/1/07, Neil: esl-lounge.com <neil at esl-lounge.com> wrote:
>> Ah! I'd been reading your previous answer trying to work out its mystic
>> meaning. :-)
>>
>> So I can't use Access Control to prevent underscores? Looks like I'll 
>> have
>> to look more closely at the other earlier responses to my question.
>>
>> ----- Original Message -----
>> From: "Cog Rusty" <cog.rusty at gmail.com>
>> To: <support at drupal.org>
>> Sent: Wednesday, August 01, 2007 6:09 PM
>> Subject: Re: [support] getting the underscore to be unusable in user 
>> names
>>
>>
>> > On 8/1/07, Cog Rusty <cog.rusty at gmail.com> wrote:
>> >> On 8/1/07, Neil: esl-lounge.com <neil at esl-lounge.com> wrote:
>> >> > I found a post on drupal.org that said you could do all of this via
>> >> > Access
>> >> > Rules.
>> >> >
>> >> > http://drupal.org/node/29694
>> >> >
>> >> > So I went there and entered the following three rules to outlaw
>> >> > underscores
>> >> >
>> >> > _% - deny/username
>> >> > %_ - deny/username
>> >> > %_% - deny/username
>> >> >
>> >> > .....and found myself and every other username blocked from the 
>> >> > site,
>> >> > unable
>> >> > to log in without getting a "this username has been reserved" error
>> >> > message.
>> >> > Totally frozen out of the site, I had to go into phpmyadmin and get 
>> >> > rid
>> >> > of
>> >> > those three entries from the "access" table. Have I ignored 
>> >> > something
>> >> > glaringly obvious with those deny rules?
>> >>
>> >>
>> >> You probably know by now. Those rules for forbidding access can do
>> >> what you want but that is just a bonus. Their main function is to
>> >> forbid access to anyone with such a username. Good idea for a new site
>> >> though.
>> >
>> > Oops! I just noticed you said "every" user. Underscore is a wildcard
>> > for any single character.
>> > --
>> > [ Drupal support list | http://lists.drupal.org/ ]
>> >
>>
>> --
>> [ Drupal support list | http://lists.drupal.org/ ]
>>
> -- 
> [ Drupal support list | http://lists.drupal.org/ ]
>