7

I have a very simple PHP function to check log-in

function check_login($user, $pass) {
    if(!isset($user) || $user == '') {
        return  'Please enter a valid username';
    }
    else if(!isset($pass) || $pass == '') {
        return  'Please enter a valid password';
    }
    else {
        return 'true';
    }
}

How can I return an error message and false same time and return true instead of 'true' as a string. Like,

function check_login($user, $pass) {
    if(!isset($user) || $user == '') {
        return  'Please enter a valid username' //return false;
    }
    else if(!isset($pass) || $pass == '') {
        return  'Please enter a valid password' //return false;
    }
    else {
        return true;
    }
}

So I can check like if(check_login($uname, $pword)){ instead of checking like if(check_login($uname, $pword)=='true'){ :)

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0

7 Answers 7

Reset to default
14

Why not just check if it's true, and handle from there.

$login = check_login('user', 'pass');

if($login === true)
    loginUser(); //login was successful, finalize or whatever
else
    echo $login; //error message
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2 Comments

Thank you for this answer. I was able to do like if($login == true) but failed. Issue was == instead of ===. Thank you!
it's so obvious yet I missed this idea. Thanks for the answer.
10

Another method you could use is to set an error message inside the class and call a function to fetch it later.

  class exampleClass {
        private $error_message = '';

        function exampleFunction($argument) {

            if($argument == 'lemons') {
                return true;
            } else {
                $this->error_message = 'Argument was not lemons.';
                return false;
            }

        }

        function getErrorMessage() {
            return $this->error_message;
        }

    }

    $example_session = new exampleClass();

    if( ! $example_session->exampleFunction('apples') )
        echo $example_session->getErrorMessage();
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7

I know this is kinda an old post, but, it gets a lot of reviews. So let me just add another answer to the great answers here.

One solution would be to pass a variable by reference like PHP style. Example

Pseudo code:

The function

 //Notice the '&' before the variable name. 
function check_login($user, $pass, &$message) {
    if(!isset($user) || $user == '') {
        $message["status"] = false;  //fail
        $message["message"] ='Please enter a valid username';
    }
    elseif(!isset($pass) || $pass == '') {
           $message["status"] = false;  //fail   
           $message["message"]=  'Please enter a valid password';
    }
    elseif (isset($pass) || $pass != ''){
         $message["status"] = true; //success
         $message["message"]=  'Username and password are valid';
        return true;
    }
       
    return false;//you can return from within the if condition if you wish
}

The Call:

/* $message variable will be assigned and populated in the function check_login() */


 
    if(check_login($uname, $pword, $message = []) === true )
    {
       //Do your stuff here
      //@message array is avaialble 
       echo message["message"];
    }
    else
    {
     //means false
     echo message["message"];
    }
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2 Comments

This is a good approach. Additionally, you could initiate $message on the function call itself: check_login($uname, $pword, $message = []) for brevity.
Thank you @AugustoMoura for your suggestion. Indeed, that is much better declaration since it will be only used in that scope.
5

Why not try throwing an exception

function check_login($user, $pass) {
    if (empty($user)) {
        throw new InvalidArgumentException('Please enter a valid username');
    }
    if (empty($pass)) {
        throw new InvalidArgumentException('Please enter a valid password');
    }
    return true
}

// snip

try {
    check_login($userValue, $passValue);
} catch (Exception $e) {
    // an error occurred
    echo $e->getMessage();
}
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4 Comments

Sometimes we need to berform both validations and retur both errors. In this case we should extend \Exception with methods like addError($key, $msg), setErrors(array $errors), getErrors(), getErrorsByKey($key) etc etc. What do you think?
@Kirzilla I think it has nothing to do with the above question and this answer. You should probably ask in a new question
@Phil Please I have a question, why you didn't use InvalidArgumentException inside catch ? Why did you use the parent class instead ? thank you
@JavaQueen because I had no reason to detect a specific exception type. Also, it'd just a very short example
0

You can use echo and return both:

function check_login($user, $pass) {
    if(!isset($user) || $user == '') {
    echo "Please enter a valid username";
        return false;
    }
    else if(!isset($pass) || $pass == '') {
    echo "Please enter a valid password";
        return false;
    }
    else {
        return true;
    }
}
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1 Comment

echo does not return the message, it displays the message and hence cannot be trapped.
0

You can use variables instead of echo or return that is much more safer than echo - let's say if you want to run this function in html header or even before that - what will you are going to see text that are generated even before website is loaded.

use variables instead ! 

    function check_login($user, $pass) {
            if(!isset($user) || $user == '') {
            $var = "Please enter a valid username";
$var = array();
    $var['msg'] = "Please enter a valid username";
    $var['error'] = "false";
    return $var;

            }
            else if(!isset($pass) || $pass == '') {
            $var = array();
    $var['msg'] = "Please enter a valid username";
    $var['error'] = "false";
    return $var;
            }
            else {
                return true;
            }
        }

that's how you can use both at the same time now where ever you want to show the error use the variable and where ever you want to check the statement check it by true and false.

Where ever you want to use the $var variable with error msg use this -

echo $var['msg'];

and when you want to check false use 

$var['error'] == 'false'
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3 Comments

Where will $var be accessed?
Yes, but that's only visible inside check_login(). He wants to handle the error messages outside that function.
So you mean you will always return an array, one index for status and another index for the message string.
0

Create an errorLog class with two methods:

class errorLog {

private $reports = array();

    public function __construct() {
    
    }
    
    public function set($fn, $message) {
    
        if(!array_key_exists($fn, $this->reports)) {
        
        $this->reports[$fn] = $message;
        
        return true;
        
        }
    
    return false;
    
    }
    
    public function get($fn) {
    
    return ($this->reports[$fn] ?? null);
    
    }

}

$errorLog = new errorLog;

Now, whenever an error occurs on in function/method, do the following:

exampleFunction($value, $errorLog) {

    if($value == "correct_value") {
    
    return true;
    
    } else {
    
    $errorLog->add(__FUNCTION__, "Wrong value!");
    
    }

return false;

}

The function call itself looks like this:

if(exampleFunction("incorrect_value", $errorLog)) {

// Success (function returned TRUE)

} else {

// Display error
echo $errorLog->get("exampleFunction");

}

The predefined constant __FUNCTION__ is used to store, and then - if needed - retrieve the corresponding errors.

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