Set checkbox values of form according to session keys

[jds43]

Hello, I have a custom form featuring 9 checkboxes. The user makes their selections and submits to set a session called "itinerary" with key (foodie) and value (1) for each selection. How can I populate those checkboxes based on the "itinerary" session when the form is viewed again. I've referenced Skyscrapers, but wasn't able to apply it here. Also, would I need to sanitize user input for a checkbox? If so, would I do so in the loop before whitelisting? ($value = $sanitizer->selectorValue($value))

    if(isset($_GET['submit'])) {
      
        // Remove existing "itinerary" sessions
        $session->remove('itinerary');
    
        // Loop through all inputs to create an associative array for storing selected checkboxes in session
        foreach($input->get() as $key => $value) {
        	$value = (int) $value; 
        	$input->whitelist($key, $value);
        	$itinerary[$key] = $value;
        }

        $session->set("itinerary", $itinerary);        
        $session->redirect($page->url);
    
    }
    echo "<pre>".var_dump($session->itinerary)."</pre>";

 

array(4) { ["foodie"]=> int(1) ["love-birds"]=> int(1) ["family"]=> int(1) ["submit"]=> int(1) }

 

[jds43]

I placed this within each input of the form based on the name of the field and it works.

if(is_array($session->itinerary) && array_key_exists('foodie', $session->itinerary)) echo 'checked';

Still not clear about sanitizing the input from the initial form submittal though.