[RESOLVED] User registering form Parse error

tinder

I am writing a user registering for my website.
I have some problem with the form validation script.
I will have a setting in config.php to set max/min length of username and password.
When I try to use the variable $min in preg_match, I get a Parse error.
Can you help?

Another question.
What max length is good to have?

Here is code

<?php
$username_min =  6; // set in config.php
$username_max = 16; // set in config.php

$msg='';
$username = isset($_POST['username']) ? trim($_POST['username']) : '';
if(!empty($username)){
    $min = $username_min-2;
    $good=preg_match( "/^[a-z][a-z0-9_]{$min,}[a-z0-9]$/", $username);
    if($good){
        session_start();
        $_SESSION['reg_uname']=$username;
        // here give link to Continue and submit password
        $msg='good';
    }else{
        $msg='bad, please try again';
    }
}
?>
<form   action=""
        method="post">
Username:
<input  type="text"
        name="username"
        value="<?php echo $username; ?>"
        maxlength="<?php echo $username_max; ?>"><br />
<input  type="submit"
        name="submit"
        value="Submit">
</form>
<?php echo $msg; ?>

laserlight

What is the parse error that you get? On which line is it?

EDIT:
Okay, I see the problem. Basically, my policy is to use single quote delimited strings for regex patterns. In this case, use:

$good = preg_match('/^[a-z][a-z0-9_]{' . $min . ',}[a-z0-9]$/', $username);

tinder

laserlight wrote:
What is the parse error that you get? On which line is it?

EDIT:
Okay, I see the problem. Basically, my policy is to use single quote delimited strings for regex patterns. In this case, use:
$good = preg_match('/^[a-z][a-z0-9_]{' . $min . ',}[a-z0-9]$/', $username);

Thanks, I will try this.

My other question was, how long should one allow a username or password to be?
I was thinking like 16 or 20.

How about length of email?
Some email addresses can be very long ....

tinder

I tested.
Now it works perfectly! 🙂
Thanks

tinder

My other question was, how long should one allow a username or password to be?
I was thinking like 16 or 20.

How about length of email?
Some email addresses can be very long ....

laserlight

My other question was, how long should one allow a username or password to be?
I was thinking like 16 or 20.

Looking around here, it seems that most people have usernames no more than a dozen characters long, and I did not find any thread starter with a username longer than 16 characters in the first few pages of the Newbies forum.

However, it seems to me that if you are choosing between 16 and 20, 20 would be a better choice since it does not so severely restrict your users.

How about length of email?
Some email addresses can be very long ....

True, but you probably do not want to alienate users on the basis of their email address. It may be long, but it is their email address.

tinder

thanks
I think I may allow at least 20 characters for username.
For Email Address I consider 64 characters.

this is 64 characters:

http://phpbuilder.com/board/newreply.php?do=newreply&noquote1234

Thanks for help.
I mark this Resolved.

Horizon88

Why bother limiting emails OR usernames OR passwords? It's just a few bytes for you - for them it means not needing to remember ANOTHER username/password combo. I could possibly see limiting the usernames, but certainly not passwords - the longer the better, in that case - and email addresses could be quite long, but 64 is probably reasonable, if you're set on limiting it. :/