Passing variables out of a function - php

Question

So, every page looks for 4 things, $e,$w,$n and $success.
$e is an array where errors are set. In every function errors are set with $e[] = 'error message';
Same for $w that is for warnings, $n for notices and the obvious for $success.
Now if the function has errors it shouldn't go ahead with the operations it's set to do, where as notices and warning are just for informing purposes.
The pages check for all of those and display each one in closeable coloured divs.
so here is my question...
I don't think this will work as expected.
Will this return the variable itself, or does this just show the contents of the variables when the function is run?
function add_member()
{
global $dbh;
if (!isset($_POST['username'],$_POST['password'],$_POST['email'])) {
$e[] = 'We need the minimum of a username and password to add a new user';
}
$regex = '/^[_a-z0-9-]+(\.[_a-z0-9-]+)*#[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$/';
if (!preg_match($regex, $_POST['email'])) {
$e[] 'The email address is wrong';
}
$stmt = $dbh->prepare("SELECT `username` FROM `1_members` WHERE `username`=? LIMIT 1");
$username = strtolower($_POST['username']);
$username = trim($username);
$stmt->bindValue(1, $username, PDO::PARAM_STR);
$stmt->execute();
if ($stmt->rowCount()) {
$e[] = 'That username is already in use';
}
if (($_POST['password']) !== ($_POST['vpassword'])) {
$e[] = 'The passwords did not match.';
}
if (strlen($_POST['username']) <= '3') {
$e[] = 'Username too short - needs to be 4 or more chars.';
}
if (strlen($_POST['password']) <='5'){
$e[] = 'password not long enough, please make it 6 chars.';
}
if (!isset($_POST['vpassword'])) {
$w[] = 'Warning: You didn\'t verify the password. Incase of typo the password was ['..']';
}
if (!isset($_POST['email'])) {
$w[] = 'Warning: You didn\'t enter an email address the password. This member will not get email alerts without an email address.';
}
if ($e) {
return $e;
}
else {
$password = trim($_POST['password']);
$options = ['cost' => 12,];
$password = password_hash($password, PASSWORD_BCRYPT, $options);
$email = trim($_POST['email']);
$stmt = $dbh->prepare("INSERT INTO `1_members` (`username`, `password`, `email`) VALUES(?,?,?)");
$stmt->bindValue(1,$username,PDO::PARAM_STR);
$stmt->bindValue(2,$password,PDO::PARAM_STR);
$stmt->bindValue(3,$email,PDO::PARAM_STR);
$stmt->execute()
$success = 'added member '.$username.'';
if (isset($w)) {
return $w;
}
if (isset($n)) {
return $n
}
return $success;
}
}

Answer 1

This function will return possibly 4 different things, and unless there is a massive error somewhere in the database setup, it shouldn't display anything. Instead, it'll return variables:
$e (array) if account can't be created due to a validation error or duplication
$w (array) if there is a warning after account creation
$n (array) if there is a notice after creation -- except that never happens. $n is not declared.
$success (string) otherwise
This function is all over the place - unpredictable. Whatever calls it will have to do a bunch of logic to deal with its return. Possibly a better way to do this is to return a richer construct. For example:
function add_member() {
$return_info = array(
"errors" => array(),
"warnings" => array(),
"notices" => array(),
"created" => false # sometimes a simple true / false is good enough
);
// do validation as before
// ...
if( $_POST['password'] !== $_POST['vpassword'] ) {
$return_info["errors"][] = "Passwords didn't match.";
}
// if account IS created, just flip the created switch
// ...
$try_inserting = $stmt->execute();
if( $try_inserting ) { # replace this with an actual error check
$return_info["created"] = true;
}
// now everything comes back: creation status, warnings, errors, etc...
return( $return_info );
}
This function refactoring standardizes all of its returns, so that it's predictable in dealing with it. You can do simple statements like:
$attempt = add_member();
if( $attempt["created"] === true ) {
echo "added member!";
}
Whatever is calling this can also do very simple checks for errors, warnings, notices:
if( !empty($attempt["errors"]) ) {
// display the errors
}