regexp on username

notset

Hello,

username in my system can contain only letters, digits and these characters: - \ . if they are not in the beggining and not in the end of username.

For example:

kak89-k OK
-kak89 WRONG
kak89_ WRONG

Could somebody post regexp for this validation?

Thank you.

NogDog

untested:

if(preg_match('/^[a-z\d]([a-z\d\-\\\\.]*[a-z\d])?$/i', $username))
{
  // OK
}
else
{
  // invalid
}

bradgrafelman

Other than the missing ')' to close the if() statement, NogDog's code should work just fine.

NogDog

bradgrafelman wrote:
Other than the missing ')' to close the if() statement, NogDog's code should work just fine.

What missing ")"? Imagine innocent whistling at this point.

suntra

I don't see any error with the if statement...

But notset asked for 3 additional characters : - \ .

I don't see anything about the backslash...

NogDog

suntra wrote:
I don't see any error with the if statement...

Note the "last edited..." message at the bottom of my first reply. 😉

But notset asked for 3 additional characters : - \ .

I don't see anything about the backslash...

They're in there, except I see I forgot to escape the hyphen, so I'm off to re-edit the original reply again...

if(preg_match('/^[a-z\d]([a-z\d[color=red]\-\\.[/color]]*[a-z\d])?$/i', $username))

rkolbe

NogDog wrote:
Note the "last edited..." message at the bottom of my first reply. 😉

They're in there, except I see I forgot to escape the hyphen, so I'm off to re-edit the original reply again...
if(preg_match('/^[a-z\d]([a-z\d[color=red]\-\\.[/color]]*[a-z\d])?$/i', $username))

-\. this is the stuff....

The . is so that . isn't taken into the regex as "everything"....

NogDog

Within a character class, "." is treated simply as a period, not a wildcard.

xblue

But wouldn't need the backslash need more escaping to make it work?
(From the manual:
Note: Single and double quoted PHP strings have special meaning of backslash. Thus if \ has to be matched with a regular expression \, then "\\" or '\\' must be used in PHP code. )

NogDog

Yep...off to re-edit again...

Tested version:

<?php
$testData = array('this\\is-valid.name', '-invalid1', 'invalid2.', '\\invalid3');
foreach($testData as $username)
{
   if(preg_match('/^[a-z\d]([a-z\d\-\\\\.]*[a-z\d])?$/i', $username))
   {
     echo "<p>'$username' is valid</p>\n";
   }
   else
   {
     echo "<p>'$username' is NOT valid</p>\n";
   }
}
?>

Output:

'this\is-valid.name' is valid
'-invalid1' is NOT valid
'invalid2.' is NOT valid
'\invalid3' is NOT valid

notset

NogDog wrote:
Output:
'this\is-valid.name' is valid

But [/B] can't be in name. How to detect it? Thank's.

NogDog

notset wrote:
But [/B] can't be in name. How to detect it? Thank's.

That's not what your original post said:

username in my system can contain only letters, digits and these characters: - \ . if they are not in the beggining and not in the end of username.

Anyway, just edit the [a-z\d-\\.] character class to include whatever characters are to be allowed in the middle of the name.

notset

Oh, sorry. My mistake... Thank you.