How should I handle the case in which a username is already in use?
- by idealmachine
I'm a JavaScript programmer and new to PHP and MySQL (want to get into server-side coding). Because I'm trying to learn PHP by building a simple online game (more specifically, correspondence chess), I'm starting by implementing a simple user accounts system. Of course, user registration comes first.
What are the best practices for:
How I should handle the (likely) possibility that when a user tries to register, the username he has chosen is already in use, particularly when it comes to function return values?($result === true is rather ugly, and I'm not sure whether checking the MySQL error code is the best way to do it either)
How to cleanly handle varying page titles?($gPageTitle = '...'; require_once 'bgsheader.php'; is also rather ugly)
Anything else I'm doing wrong? In some ways, PHP is rather different from JavaScript...
Here is a (rather large) excerpt of the code I have written so far. Note that this is a work in progress and is missing security checks that I will add as my next step.
function addUser( $username, $password ) {
global $gDB, $gPasswordSalt;
$stmt = $gDB->prepare( 'INSERT INTO user(user_name, user_password, user_registration) VALUES(?, ?, NOW())' );
$stmt || trigger_error( 'Failed to prepare statement: ' . htmlspecialchars( $gDB->error ) );
$hashedPassword = hash_hmac( 'sha256', $password, $gPasswordSalt, true );
$stmt->bind_param( 'ss', $username, $hashedPassword );
if( $stmt->execute() ) {
return true;
} elseif( $stmt->errno == 1062) {
return 'exists';
} else {
trigger_error( 'Failed to execute statement: ' . htmlspecialchars( $stmt->error ) );
}
}
$username = $_REQUEST['username'];
$password = $_REQUEST['password'];
$result = addUser( $username, $password );
if( $result === true ) {
$gPageTitle = 'Registration successful';
require_once 'bgsheader.php';
echo '<p>You have successfully registered as ' . htmlspecialchars( $username ) . ' on this site.</p>';
} elseif( $result == 'exists' ) {
$gPageTitle = 'Username already taken';
require_once 'bgsheader.php';
echo '<p>Someone is already using the username you have chosen. Please try using another one instead.';
} else {
trigger_error('This should never happen');
}
require_once 'bgsfooter.php';
