Question

I need an advice how to handle function with lots of different return’s better.
I have this simple log in function in my class:

public function login($email, $password){

$record = // Go to database and find what we need.

if($record){
   // Check pass, $user_match = TRUE;
} else {
   return 1;         //No such user. Please register!
}

$active = (1 == $record['is_active']) ? TRUE : FALSE;
$verified = (1 == $record['is_verified']) ? TRUE : FALSE;

//User email and password matched:
if($user_match == true){
   if($verified === true){
       // Start session and insert to db table "online_users"
   // Check that user was inserted to table: $confirm = $stmt->rowCount();

         if($confirm !== 1){
           return 2; //Unexpected technical error. Please try again in a moment.
         }

       return 0;     //0 means that all clear, we good to go.

       } else {
           return 3; //not verified
       }
    } else {
        return 4;    // no match with email and pass, reject!
    }
}

The problem is, that now all the time I need to check all return’s, something like that:

$log = $user->login($_POST['email'], $_POST['pass']);
if($log === 0) {
    //Log in & edirect
} elseif ($log === 1) {
    //No such user. Tell to register
} elseif($log === 2){
    //technical error, try again
} elseif($log === 3){
    //Not verified
} elseif($log === 4){
    //wrong password

It’s really annoying right now, and imagine if I would need to check like 20 return’s? Is there any better way? How to do it more efficient and faster?
Thanks in advance.

Answer 1

You should rethink the purpose of this function and structure the return types accordingly. If the purpose is to log the user in, there can only be one answer: it either worked or it didn’t. So the primary return type of the function should be a boolean. How to differentiate between different causes for failure is a different topic.

Option 1: throw exceptions:

try {
    if (!$foo->login()) {
        echo 'Invalid credentials';
    }
} catch (UserNotActiveException $e) {
    ...
} catch (UserNotValidatedException $e) {
    ...
}

Not necessarily the most elegant option, since a failed login isn’t really an exceptional circumstance.

Option 2: save the error state in the login provider:

if (!$foo->login()) {
    echo "You're not logged in because ", $foo->loginError();
}

Whether this is good or not depends on how the class is used otherwise, you may not want to make it too stateful.

Option 3: separate the problem of login from what is the user’s state entirely:

if (!$foo->login($user)) {
    switch ($foo->currentStatus($user)) {
        case $foo::ALL_OK :
             echo 'Login credentials invalid';
             break;
        case $foo::ACCOUNT_INACTIVE :
             ...
    }
}

Option 4: return a status object:

$result = $foo->login();
switch ($result->status) {
    case $result::ALL_OK :
        ...
}

That’s essentially what you’re doing now, just without the magic numbers.