Form Validation Issues

Rollo_Tamasi

Hello. I'm new to php and i'm having one or two problems attempting to validate the fields in a form. I wan't to make sure that no characters such as $£%£^ or numbers are used in the username field when the user attempts to sign up. I also want to make sure that the user picks a username that is more than 6 characters in length but less than 10.

I'm sure this is simple enough to resolve as i am of little php experience i was wondering if maybe one of you could help a little with finding the error(s). The code is missing one or two elements to get it to work properly. This is the excerpt from the code which is causing the problem. I keep getting an error on line 41 stating "Call to undefined function: ctype_alpha()"

<?

include 'db.php';


// Define post fields into simple variables
$first_name = $_POST['first_name'];
$last_name = $_POST['last_name'];
$email_address = $_POST['email_address'];
$username = $_POST['username'];
$info = $_POST['info'];

/* Let's strip some slashes in case the user entered
any escaped characters. */

$first_name = stripslashes($first_name);
$last_name = stripslashes($last_name);
$email_address = stripslashes($email_address);
$username = stripslashes($username);
$info = stripslashes($info);



/* This is the Error Checking Validation Fields. This is where the problem lies */

if((!$first_name) || (!$last_name) || (!$email_address) || (!$username) || (!$username)){
	echo 'You did not submit the following required information! <br />';
	if(!$first_name){
		echo "First Name is a required field. Please enter it below.<br />";
	}
	if(!$last_name){
		echo "Last Name is a required field. Please enter it below.<br />";
	}
	if(!$email_address){
		echo "Email Address is a required field. Please enter it below.<br />";
	}
	if(!$username){
		echo "Desired Username is a required field. Please enter it below.<br />";
	}

if(!(ctype_alpha($username)) || ($username == "") || ($username == NULL) || (strlen($username) < 5) || (strlen($username) > 15)){
echo "You have an invalid username.  It must be between 5 and 15 characters and can only contains letters a-zA-Z. <br />";
} 

include 'join_form.html'; 
exit(); 
}

i also have or two other problems with the form which i may ask as well but the validation is the important thing at the moment. Thanks very much to anybody who can help me in this matter.

Kudose

echo (eregi("^[\x20A-Za-z]{5,15}$", $user)) ? 'Valid' : 'Error';

Kudose

Also, you are comparing $user when you declared $username

Rollo_Tamasi

Kudose wrote:
Also, you are comparing $user when you declared $username

sorry that was my mistake, i had $username in the original coding, i copied and pasted the $user code from another script i had. I'll give the code you submitted a try , thanks for your response.

Installer

What version PHP are you using? It must be an old one if ctype_alpha isn't available.

The outer if block appears to be unnecessary, since you check for the same conditions in the inner blocks.

Where is "$user" defined? Is that supposed to be "$username", or is it defined in the included file?

Rollo_Tamasi

Installer wrote:
What version PHP are you using? It must be an old one if ctype_alpha isn't available.

The outer if block appears to be unnecessary, since you check for the same conditions in the inner blocks.

Where is "$user" defined? Is that supposed to be "$username", or is it defined in the included file?

i edited the code and changed user to username. That was my mistake.
I'm using PHP 4.2.3.

which is the outer If block that you are refering to? I got the code to complie properly now but for some reasons the php code won't read in the arguement. The code i got to work is...

if(!preg_match('/^[a-z]{5,15}$/i', $username)){ 
		echo "your username contains invalid characters. <br />";
	}

however users can still sign up with a $%^$ in their username. Any ideas?

Installer

You can use something like this to check for alpha characters:

$alpha = array_merge(range('A', 'Z'), range('a', 'z'));
for ($i = 0; $i < strlen($username); $i__) {
    if (!in_array($username{$i}, $alpha)) {
        echo 'Letters only';
        break;
    }
}

Edited for typos.