preg_match

[MySQL_Narb]

if(preg_match('/[^a-zA-Z0-9_ ]/', $username)) $err = 1;

 

Any idea why that returns:

 

Warning: preg_match() [function.preg-match]: No ending delimiter '^' found in /home/a4205434/public_html/structure/user.register.php on line 64

[xyph]

No error generated with that code here. You've messed up elsewhere

[MMDE]

I got a feeling you're trying to do this instead:

preg_match('/^[a-zA-Z0-9_ ]/', $username)

Though, this can not be used to sanitize input, as it matches always when the first letter in one of the lines in $username is one of these: "a-zA-Z0-9_ ", no matter what is afterwards, or if it is several lines.

 

I think you want this:

if(preg_match('/\A[a-zA-Z0-9_ ]+\Z/', $username)){
//$username is "safe" to use in a mysql query
}

 

Please do correct me if this is not a good regex to sanitize user input.

[Christian F.]

MMDE: If you take a second look at the code he posted, it'll set $err = 1 if the pattern matches. In other words, exactly what you'd want for validation.