PHP AJAX Form Helper Functions

gistfile1.php

<?php

/**
 * JSON response builder, useful for AJAX request
 * forms. Provides a nice way to send messages
 * back to the view
 *
 * @param $type
 * @param $message
 */
function response($type, $message) {
    echo json_encode(['type' => $type, 'message' => $message]);
}

/**
 * Only allow data from post and get to be stored in
 * the database. Will return false if posted data
 * does not match allowed data
 *
 * @param array $values
 * @param array $allowed
 * @return bool
 */
function allowedData($values = [], $allowed = []) {
    foreach($values as $key => $value) {
        if(!in_array($key, $allowed)) return false;
    }

    return true;
}

// Pass through POST or GET data and specify 
// posted data that is allowed through
$guarded = allowedData($_POST, [
    'posted_name_1',
    'posted_name_2'
    ...
]);

// Return a response
if($guarded) {
    response('success', 'Guard passed');
    ...
} else {
    response('error', 'Invalid POST data submitted');
}