如何将$ _SESSION变量传递给函数

Question

I am trying to pass my $_SESSION variables into a database query function for WordPress. If I define the $_SESSION variables within the function it works fine. But when I define them on a global level and try to pass them in, they do not pass through. Please view below for examples.

This will pass through to the function below

$_SESSION['pages'] = $_POST['pages'];

But when I add

$pages = $_SESSION['pages'];

$pages will not pass through to the function.

    $_SESSION['pages'] = $_POST['pages']; //passes
    $pages = $_SESSION['pages']; //does not pass

function insertLocalBusinessSchema()
    {
        //include global config  
        include_once($_SERVER['DOCUMENT_ROOT'].'/stage/wp-config.php' );

        global $wpdb;

        // if I try to define this outside of the function it doesn't pass through.
        $pages = implode(',', $_SESSION['pages']);

        $paymentAccepted = implode(',', $_SESSION['paymentAccepted']);

        $table_name = $wpdb->prefix . "schemaLocalBusiness";

        $insert = "UPDATE ".$table_name." SET addressLocality = '".$_SESSION['addressLocality']."', addressRegion = '".$_SESSION['addressRegion']."', postalCode = '".$_SESSION['postalCode']."', streetAddress = '".$_SESSION['streetAddress']."', pages = '".$pages."', paymentAccepted = '".$paymentAccepted."' WHERE id = 1";

        $wpdb->query($insert);

    }

Thank you for the help in advance!

Answer 1

$_SESSION is a global variable and so you can call it from anywhere you wish, while $pages is not defined globally so you would need to pass it as a parameter to the function like this:

function insertLocalBusinessSchema($pages)
{
    echo $pages; // the variable is now in the function's scope
}

You would then call the function passing the parameter for $pages:

insertLocalBusinessSchema($pages);

If you wish to use the variable $pages inside the function without passing its value as a parameter, you can do it by using the $GLOBALS PHP super global variable like this:

// super global variable GLOBALS
$GLOBALS['pages'] = $_POST['pages'];

function insertLocalBusinessSchema()
{
    echo $GLOBALS['pages']; // this also works
}

more here.

Or you can use the global keyword like this:

$pages = $_POST['pages'];

function insertLocalBusinessSchema()
{
    global $pages;  // $pages becomes global
    echo $pages;    // this also works
}