Question

I am writing a login script for my website. I’ve written the login script, and I have the form tied to it via an AJAX call through jQuery.

Here is the php the form is calling:

<?PHP   
    # Make sure form data was passed to the script
    IF (isset($_POST) && isset($_POST['username']) && isset($_POST['password'])){
        # Connect to the database
        REQUIRE('../../../../my_db.php');

        # Define variables
        $given_username = $_POST['username'];
        $given_password = $_POST['password'];
        $hashed_password = md5($given_password);
        $matched_username = "";
        $matched_password = "";


        # See if there is matching info in the database
        $sql = 'SELECT username, pass FROM users WHERE username="'.$given_username.'" AND pass = "'.$hashed_password.'"';
        $result = mysql_query($sql);
        WHILE($row = mysql_fetch_assoc($result)){
            $matched_username = $row['username'];
            $matched_password = $row['pass'];
        };


        # If there was a match
        IF ($matched_username != "" && $matched_password != ""){

            # Double check the values match
            IF ($given_username == $matched_username && $hashed_password == $matched_password){

                # If there is only one result returned
                $session_sql = 'SELECT * FROM users WHERE username="'.$matched_username.'" AND pass = "'.$matched_password.'"';
                $session_result = mysql_query($session_sql);
                IF(count(mysql_fetch_assoc($session_result)) != 0  &&  count(mysql_fetch_assoc($session_result)) < 2){

                    # If they do, start a session
                    if(!isset($_SESSION)) {
                     session_start();
                     session_regenerate_id();
                    };

                    # Set our session values
                    WHILE($session_row = mysql_fetch_assoc($session_result)){
                        $_SESSION['id'] = $session_row['id'];
                        $_SESSION['last_login'] = $session_row['last_login'];
                        $_SESSION['username'] = $session_row['username'];
                        $_SESSION['signup_date'] = $session_row['signup_date']; 
                    };

                    # Set users last login date and time to this login
                    $update_sql = 'UPDATE users SET last_login = NOW WHERE username="'.$matched_username.'" AND pass = "'.$matched_password.'"';
                    $update = mysql_query($update_sql);

                    echo json_encode(array("success"=>"user logged in", "session"=>$_SESSION));
                }ELSE 
                    echo json_encode(array("error"=>"More than one user with the same information.  What did you do?!"));
            }ELSE
                echo json_encode(array("error"=>"invalid login provided"));
        }ELSE
            echo json_encode(array("error"=>"invalid login provided"));
    }ELSE
        echo json_encode(array("error"=>"you must supply a username and password"));
?>

But if I do console.log(result.session) I get [], which makes me think that either setting session variables through ajax isn’t viable, or the session itself isn’t working properly.

I get no errors from this code.

Can somebody point me in the right direction?

I don’t think I have access to php.ini, but I remember from a long time ago that you had to set sessions to run in a file somewhere, but for the life of me I can’t find an example.

Answer 1

Make sure you have session_start() at the beginning of your script. If any notices or anything is thrown before you get to session_start() then you’ll get an error like this:

Warning: session_start(): Cannot send session cookie – headers already sent by (output started at…

Also, your script is open to SQL injection. Make sure you properly escape the username and password! Note: your best bet is to use prepared statements.