set('Cache.DefinitionImpl', null); // Disable cache by setting a non-existent directory or an invalid one
$purifier_config->set('URI.AllowedSchemes', ['data' => true, 'src' => true, 'http' => true, 'https' => true]);
$purifier = new HTMLPurifier($purifier_config);
$document_id = intval($_GET['id']);
$sql = mysqli_query($mysqli, "SELECT * FROM documents WHERE document_id = $document_id LIMIT 1");
$row = mysqli_fetch_array($sql);
$document_name = nullable_htmlentities($row['document_name']);
$document_content = $purifier->purify($row['document_content']);
// Generate the HTML form content using output buffering.
ob_start();
?>