If php $_SESSION variable has data

Question

I am new to php. I am trying to check if the session variable has a value? If yes do nothing else set value. This is my code:

if (isset($_POST['ProductName'])) {
    if (!empty($_SESSION['UserBasketID'])) {
        $order = $_POST['ProductName'];
        $date = date("Ymd");
        $_SESSION['UserBasketID'] = $date.$order;
        var_dump($_SESSION['UserBasketID']);            
    } else {
        echo 'The session is set';
        if (isset($_SESSION['UserBasketID'])) {
            var_dump($_SESSION['UserBasketID']);
        }
    }
}

And can somebody tell me how it works in php.

M. Eriksson · Accepted Answer · 2019-03-16 11:47:07Z

1

Your if-condition is backwards.

empty() returns true if the variable in not set or if it contains an empty value.
!empty() (with the ! in front of it) returns true if the variable is set and doesn't contain an empty value.

So the code:

if (!empty($_SESSION['UserBasketID']))

will evaluate as true if the session is defined and has a non-empty value, which means that you're currently only setting the session if it's already set.

Remove the ! in front of empty() and it should work:

if (isset($_POST['ProductName'])) {
    if (empty($_SESSION['UserBasketID'])) {
        $order = $_POST['ProductName'];
        $date  = date("Ymd");
        $_SESSION['UserBasketID'] = $date . $order;
        var_dump($_SESSION['UserBasketID']);            
    } else {
        echo 'The session is set';

        // We can remove the if-statement here since we
        // we've already checked it
        var_dump($_SESSION['UserBasketID']);
    }
}

answered Mar 16, 2019 at 11:47

M. Eriksson

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2 Comments

Andeas Walz Over a year ago

I just try out it and it rewrite my session variable by clicking on another item. Är du svensk?

M. Eriksson Over a year ago

@AndeasWalz - That's a totally different issue though. If this solves that specific issue in your question, you should accept it. If you got some other issue, then you should write a new question where you include a proper explanation and all the relevant code. And yes, jag är svensk :-)

nickl- · Accepted Answer · 2019-03-16 14:55:31Z

0

The php documentation states that since 7.1.0:

session_start() now returns FALSE and no longer initializes $_SESSION when it failed to start the session.

So the correct way to check if the session property is set will now be:


if (session_start() && isset($_SESSION['UserBasketID'])) {
   // $_SESSION['UserBasketID'] is set
} else {
   // Either no session, $_SESSION not initialized or $_SESSION['UserBasketID'] not set
}

answered Mar 16, 2019 at 14:55

nickl-

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