刷新后无法访问PHP会话变量

Question

I got a logical problem with this code:

<?php
if(isset($_POST['submit'])) {
    if($_POST['username'] != "" && $_POST['password'] != "") {
        $_SESSION["user"] = new User();
        $_SESSION["user"]->login($_POST['username'], $_POST['password']);
    }
}
?>

But after refreshing the page , the session is empty. Does somone know why the session could be empty? The login function is working correctly (tested it with fixed login data at every reload of the page).

Thanks in advance!

Answer 1

If you are storing an object in the session, you need to make sure that the class is defined (or available in an autoloader) before session_start() is called, otherwise PHP won't be able to deserialise the object.

See http://php.net/manual/en/oop4.serialization.php for more info.