Не работает вывод через $tpl->set()

<?php

if( !defined( 'DATALIFEENGINE' ) ) {
    die( "Hacking attempt!" );
}

$newsid = intval($_REQUEST['id']);
 
$row2 = $db->super_query("SELECT id, date, onserver, news_id FROM " . PREFIX . "_files WHERE news_id ='$newsid'");
   
$book = $row2['onserver'];
    
$file = ROOT_DIR . '/uploads/files/' . $book;
if(file_exists($file)) $book_data = str_replace("\n" ,"<br/><br/>\n", file_get_contents($file));
else $book_data = "указанная книги не найдена";
  
$za = new ZipArchive();
 
$zip = zip_open("$file");

if ($zip) {
    while ($zip_entry = zip_read($zip)) {
 
        if (zip_entry_open($zip, $zip_entry, "r")) {
            $buf = zip_entry_read($zip_entry, zip_entry_filesize($zip_entry));
            $def = nl2br($buf); // echo "$buf\n";
            
            $book_data = $def;
            $char_one_page = 5000; //количество букв на страницу
            $lenstr = strlen($book_data);
            $page = ceil($lenstr/$char_one_page);
            $_GET['p'] = ($_GET['p']) ? $_GET['p'] : 1;
            $text = substr($book_data,($_GET['p']*$char_one_page)-$char_one_page,$char_one_page);
            zip_entry_close($zip_entry);
        }

    }
    zip_close($zip);
}

$text = "test"; // <-- использовал для проверки 

$tpl->load_template( 'book.tpl' );

$tpl->set('{book}', $text);
$tpl->compile('content');
$tpl->result['content'];
$tpl->clear();

?>