Automatically Stamping Customer Name on PDF eBooks?

[technologynow]

And your brother in law passes it to someone else ... who passes it on to someone else ... who passes it to someone else ... who puts it as a free download on their website ... AND you get thousands of spam emails AND I take you to court.
Of course, having your email on the bottom won't stop it being passed round (just like any book that you may have written your name on the cover may be given away), and with some effort it would be possible to take the stamping off. The deterrent is having YOUR email on it. The email your PayPal account is registered to. It will, if nothing else, make people think twice.

[lat9]

For those that might be interested, here's the modified version that I'm using for /includes/modules/pages/downloads/header_php.php to work with the SetaPDF functions:

<?php
/**
 * download header_php.php
 *
 * @package page
 * @copyright Copyright 2003-2011 Zen Cart Development Team
 * @copyright Portions Copyright 2003 osCommerce
 * @license http://www.zen-cart.com/license/2_0.txt GNU Public License V2.0
 * @version $Id: header_php.php 18964 2011-06-22 19:58:38Z drbyte $
 */
// This should be first line of the script:
$zco_notifier->notify('NOTIFY_HEADER_START_DOWNLOAD');

define('SYMLINK_GARBAGE_COLLECTION_THRESHOLD', 1*60*60); // 1 hour default


require(DIR_WS_MODULES . zen_get_module_directory('require_languages.php'));

// if the customer is not logged on, redirect them to the time out page
if (!$_SESSION['customer_id']) {
  zen_redirect(zen_href_link(FILENAME_TIME_OUT));
}

// Check download.php was called with proper GET parameters
if ((isset($_GET['order']) && !is_numeric($_GET['order'])) || (isset($_GET['id']) && !is_numeric($_GET['id'])) ) {
  // if the paramaters are wrong, redirect them to the time out page
  zen_redirect(zen_href_link(FILENAME_TIME_OUT));
}

// Check that order_id, customer_id and filename match
$sql = "SELECT date_format(o.date_purchased, '%Y-%m-%d')
          AS date_purchased_day, opd.download_maxdays, opd.download_count, opd.download_maxdays, opd.orders_products_filename, o.customers_email_address
          FROM " . TABLE_ORDERS . " o, " . TABLE_ORDERS_PRODUCTS . " op, " . TABLE_ORDERS_PRODUCTS_DOWNLOAD . " opd
          WHERE o.customers_id = customersID
          AND o.orders_id = ordersID
          AND o.orders_id = op.orders_id
          AND op.orders_products_id = opd.orders_products_id
          AND opd.orders_products_download_id = downloadID
          AND opd.orders_products_filename != ''";

$sql = $db->bindVars($sql, 'customersID', $_SESSION['customer_id'], 'integer');
$sql = $db->bindVars($sql, 'downloadID', $_GET['id'], 'integer');
$sql = $db->bindVars($sql, 'ordersID', $_GET['order'], 'integer');
$downloads = $db->Execute($sql);
if ($downloads->RecordCount() <= 0 ) die;

$zco_notifier->notify('NOTIFY_CHECK_DOWNLOAD_HANDLER', array($downloads));

// MySQL 3.22 does not have INTERVAL, so must calculate dates with PHP:
list($dt_year, $dt_month, $dt_day) = explode('-', $downloads->fields['date_purchased_day']);
$download_timestamp = mktime(23, 59, 59, $dt_month, $dt_day + $downloads->fields['download_maxdays'], $dt_year);

// Die if time expired (maxdays = 0 means no time limit)
if (($downloads->fields['download_maxdays'] != 0) && ($download_timestamp <= time())) {
  zen_redirect(zen_href_link(FILENAME_DOWNLOAD_TIME_OUT));
}
// Die if remaining count is <=0 (maxdays = 0 means no time limit)
if ($downloads->fields['download_count'] <= 0 and $downloads->fields['download_maxdays'] != 0) {
  zen_redirect(zen_href_link(FILENAME_DOWNLOAD_TIME_OUT));
}

$zco_notifier->notify('NOTIFY_DOWNLOAD_DAYS_COUNT_OK');
// FIX HERE AND GIVE ERROR PAGE FOR MISSING FILE
// Die if file is not there
if (!file_exists(DIR_FS_DOWNLOAD . $downloads->fields['orders_products_filename'])) die('Sorry. File not found. Please contact the webmaster to report this error.<br />c/f: ' . $downloads->fields['orders_products_filename']);

$zco_notifier->notify('NOTIFY_DOWNLOAD_FILE_OK');

// Now decrement counter (probably should skip this if download_maxdays = 0, ie: unlimited) -- move it up to lines 48-54?
$sql = "UPDATE " . TABLE_ORDERS_PRODUCTS_DOWNLOAD . "
          SET download_count = download_count-1
          WHERE orders_products_download_id = :downloadID";

$sql = $db->bindVars($sql, ':downloadID', $_GET['id'], 'integer');
$db->Execute($sql);

// Returns a random name, 16 to 20 characters long
// There are more than 10^28 combinations
// The directory is "hidden", i.e. starts with '.'
function zen_random_name()
{
  $letters = 'abcdefghijklmnopqrstuvwxyz';
  $dirname = '.';
  $length = floor(zen_rand(16,20));
  for ($i = 1; $i <= $length; $i++) {
    $q = floor(zen_rand(1,26));
    $dirname .= $letters[$q];
  }
  return $dirname;
}

// Unlinks all subdirectories and files in $dir
// Works only on one subdir level, will not recurse
function zen_unlink_temp_dir($dir)
{
  $h1 = opendir($dir);
  while ($subdir = readdir($h1)) {
    // Ignore non directories
    if (!is_dir($dir . $subdir)) continue;
    // Ignore . and .. and .svn
    if ($subdir == '.' || $subdir == '..' || $subdir == '.svn') continue;
    // Loop and unlink files in subdirectory
    $h2 = opendir($dir . $subdir);
    list($fn, $exptime) = explode('-', $subdir);
    if ($exptime + SYMLINK_GARBAGE_COLLECTION_THRESHOLD > time()) continue;
    while ($file = readdir($h2)) {
      if ($file == '.' || $file == '..') continue;
      @unlink($dir . $subdir . '/' . $file);
    }
    closedir($h2);
    @rmdir($dir . $subdir);
  }
  closedir($h1);
}

// disable gzip output buffering if active:
@ob_end_clean();
if (@ini_get('zlib.output_compression')) @ini_set('zlib.output_compression', 'Off');

// determine filename for download
$origin_filename = $downloads->fields['orders_products_filename'];
$browser_filename = str_replace(' ', '_', $origin_filename);
if (strstr($browser_filename, '/')) $browser_filename = substr($browser_filename, strrpos($browser_filename, '/')+1);
if (strstr($browser_filename, '\\')) $browser_filename = substr($browser_filename, strrpos($browser_filename, '\\')+1);
if (substr(DIR_FS_DOWNLOAD, -1) != '/') $origin_filename = '/' . $origin_filename;
if (!file_exists(DIR_FS_DOWNLOAD . $origin_filename)) {
  $msg = 'DOWNLOAD PROBLEM: Problems detected with download for ' . DIR_FS_DOWNLOAD . $origin_filename . ' because the file could not be found on the server. If the file exists, then its permissions are too low for PHP to access it. Contact your hosting company for specific help in determining correct permissions to make the file readable by PHP.';
  zen_mail('', STORE_OWNER_EMAIL_ADDRESS, ERROR_CUSTOMER_DOWNLOAD_FAILURE, $msg, STORE_NAME, EMAIL_FROM);
}
$downloadFilesize = @filesize(DIR_FS_DOWNLOAD . $origin_filename);
if (!isset($downloadFilesize) || ($downloadFilesize < 1)) {
  $msg = 'DOWNLOAD PROBLEM: Problem detected with download for ' . DIR_FS_DOWNLOAD . $origin_filename . ' because the server is preventing PHP from reading the file size attributes, or the file is actually 0 bytes in size (which suggests the uploaded file is damaged or incomplete). Perhaps its permissions are too low for PHP to access it? Contact your hosting company for specific help in determining correct permissions to allow PHP to stat the file using the filesize() function.';
  zen_mail('', STORE_OWNER_EMAIL_ADDRESS, ERROR_CUSTOMER_DOWNLOAD_FAILURE, $msg, STORE_NAME, EMAIL_FROM);
}


/* ---- Start lat9 PDF Stamper ---
**
** Stamped file is of the format:  originalname_ordernum_downloadcount.pdf
     */
$stamp_fn_out = basename($origin_filename, '.pdf') . '_' . $_GET['order'] . '_' . $downloads->fields['download_count'] . '.pdf';

$stamp_fn_out = str_replace(' ', '_', $stamp_fn_out);

$stamp_file_out = DIR_FS_DOWNLOAD_PUBLIC . $stamp_fn_out;
$stamp_file_in = DIR_FS_DOWNLOAD . $origin_filename;

    /**
 * set the includepath for SetaPDF APIs
 * You have to point to the root directory "SetaPDF"
     */
set_include_path(get_include_path() . PATH_SEPARATOR . DIR_FS_SETAPDF);


$zco_notifier->notify('NOTIFY_DOWNLOAD_PATH', get_include_path());

// require the SetaPDF_Stamper-class
require_once("Stamper/SetaPDF_Stamper.php");


$zco_notifier->notify('NOTIFY_DOWNLOAD_STAMP_LOADED');

// Define the path, where the SetaPDF-Stamper will find the font-definition files
define('SetaPDF_STAMPER_FONTPATH', 'Stamper/font/');

// Create a new instance of SetaPDF_Stamper with output method "Download" w/buffering
$stamper =& SetaPDF_Stamper::factory('D', true);

$stamper->addFile( 
	array(
		"in"  => $stamp_file_in,
		"out" => $stamp_file_out, 
		"compression" => true
	) 
); 

// Let's create the text stamp
// require the SetaPDF_TextStamp-class
require_once("Stamper/SetaPDF_Stamp/SetaPDF_TextStamp.php");
// Initiate a new instance of text_stamp 
$textstamp =& new SetaPDF_TextStamp();
// Set the text 
$textstamp->setText("Licensed to:" . "\n" . $downloads->fields['customers_email_address']); 
// Set font definitions 
$textstamp->setFont("Arial", "B", 20, 20, "C"); 
// Set text color to red 
$textstamp->SetFontColor(255, 0, 0); 
// Set the charspacing 
$textstamp->setCharSpacing(15); 
// Set the rendering mode 
$textstamp->setRenderingMode(2); 
// Set the opacity 
$textstamp->setAlpha(0.2); 

    /**
* Now we assign the text stamp to our stamper 
* - we define the position on the center and middle of a page (CM) 
* - the stamp should appear on "all" pages 
* - no translation of the x-axis nor the y-axis will be done 
* - we rotate the stamp about 60 degree 
     */
$stamper->setStamp($textstamp,"CM", "all", 0, 0, 60); 

// Let's stamp! 
$stamper->stampit(); 
$stamper->cleanUp();

// This should be last line of the script:
$zco_notifier->notify('NOTIFY_HEADER_END_DOWNLOAD');

// finally, upon completion of the download, the script should end here and not attempt to display any template components etc.
zen_exit();

[Pasiphilo]

Awesome, lat9! Many thanks!

[joew36]

For those that might be interested, here's the modified version that I'm using for /includes/modules/pages/downloads/header_php.php to work with the SetaPDF functions:

That is really awesome, thanks for the useful info. Looks like it's just what we need.

[DrByte]

lat9,
Can I offer a potentially even more friendly implementation that doesn't make as much core code changes as your altered header_php.php does?

1. You added the email address to the SQL query. Good idea. In fact, adding ", o.*" makes all the main order details available, including the email address:

          AS date_purchased_day, opd.download_maxdays, opd.download_count, opd.download_maxdays, opd.orders_products_filename, o.*

2. Change the notifier call to pass all its parameters correctly as an array, plus the order info:

    $zco_notifier->notify('NOTIFY_DOWNLOAD_READY_TO_START', $origin_filename, $browser_filename, $downloadFilesize, $_SESSION['customers_host_address']);

becomes:

    $zco_notifier->notify('NOTIFY_DOWNLOAD_READY_TO_START', array($origin_filename, $browser_filename, $downloadFilesize, $_SESSION['customers_host_address'], $downloads->fields));

3. Add an observer class to take care of your SetaPDF custom code:
/includes/classes/observers/class.observer_download_stamped_by_setapdf.php

<?php
/**
 * @package plugins
 * @copyright Copyright 2003-2012 Zen Cart Development Team
 * @license http://www.zen-cart.com/license/2_0.txt GNU Public License V2.0
 * @version $Id$
 *
 * Designed for v1.5.0
 */

class observer_download_stamped_by_setaPDF extends base {

  function __construct() {
    $this->attach($this, array('NOTIFY_DOWNLOAD_READY_TO_START'));
  }

  function update(&$class, $eventID, $paramsArray = array())
  {
    $origin_filename = $paramsArray[0];
    $browser_filename = $paramsArray[1];
    $downloadFilesize = $paramsArray[2];
    $ip_address = $paramsArray[3];
    $orderData = $paramsArray[4];

    // if not serving a PDF file, abort this observer class and use normal download procedures.
    if (!preg_match('~\.pdf$~', $origin_filename)) return false;

    /* ---- Start lat9 PDF Stamper ---
     **
    ** Stamped file is of the format:  originalname_ordernum_downloadcount.pdf
    */
    $stamp_fn_out = basename($origin_filename, '.pdf') . '_' . $orderData['orders_id'] . '_' . $orderData['download_count'] . '.pdf';

    $stamp_fn_out = str_replace(' ', '_', $stamp_fn_out);

    $stamp_file_out = DIR_FS_DOWNLOAD_PUBLIC . $stamp_fn_out;
    $stamp_file_in = DIR_FS_DOWNLOAD . $origin_filename;

    /**
     * set the includepath for SetaPDF APIs
     * You have to point to the root directory "SetaPDF"
     */
    set_include_path(get_include_path() . PATH_SEPARATOR . DIR_FS_SETAPDF);
    // require the SetaPDF_Stamper-class
    if (file_exists("Stamper/SetaPDF_Stamper.php")) require_once("Stamper/SetaPDF_Stamper.php");
    // if the require() failed (ie: SetaPDF_Stamper.php couldn't be loaded), then abort the observer and serve the file using normal methods)
    if (!class_exists('SetaPDF_Stamper', false)) return FALSE;

    // Define the path, where the SetaPDF-Stamper will find the font-definition files
    define('SetaPDF_STAMPER_FONTPATH', 'Stamper/font/');

    // Create a new instance of SetaPDF_Stamper with output method "Download" w/buffering
    $stamper =& SetaPDF_Stamper::factory('D', true);

    $stamper->addFile(
              array(
                    "in"  => $stamp_file_in,
                    "out" => $stamp_file_out,
                    "compression" => true
                    ));

    // Let's create the text stamp
    // require the SetaPDF_TextStamp-class
    require_once("Stamper/SetaPDF_Stamp/SetaPDF_TextStamp.php");
    // Initiate a new instance of text_stamp
    $textstamp =& new SetaPDF_TextStamp();
    // Set the text
    $textstamp->setText("Licensed to:" . "\n" . $orderData['customers_email_address']);
    // Set font definitions
    $textstamp->setFont("Arial", "B", 20, 20, "C");
    // Set text color to red
    $textstamp->SetFontColor(255, 0, 0);
    // Set the charspacing
    $textstamp->setCharSpacing(15);
    // Set the rendering mode
    $textstamp->setRenderingMode(2);
    // Set the opacity
    $textstamp->setAlpha(0.2);

    /**
     * Now we assign the text stamp to our stamper
     * - we define the position on the center and middle of a page (CM)
     * - the stamp should appear on "all" pages
     * - no translation of the x-axis nor the y-axis will be done
     * - we rotate the stamp about 60 degree
    */
    $stamper->setStamp($textstamp,"CM", "all", 0, 0, 60);

    // Let's stamp!
    $stamper->stampit();
    $stamper->cleanUp();

    zen_exit();

  }
}

4. Add an auto_loader entry to enable the observer class:
/includes/auto_loaders/config.observer_download_stamped_by_setapdf.php

<?php
/**
 * @package plugins
 * @copyright Copyright 2003-2012 Zen Cart Development Team
 * @license http://www.zen-cart.com/license/2_0.txt GNU Public License V2.0
 */
/**
 * Designed for v1.5.0
 */
if (!defined('IS_ADMIN_FLAG')) {
 die('Illegal Access');
}
$autoLoadConfig[190][] = array('autoType'=>'class',
                              'loadFile'=>'observers/class.observer_download_stamped_by_setapdf.php');
$autoLoadConfig[190][] = array('autoType'=>'classInstantiate',
                              'className'=>'observer_download_stamped_by_setaPDF',
                              'objectName'=>'observer_download_stamped_by_setaPDF');

Of course, one still needs to buy a license for and install the SetaPDF code on the server for this to work.

[joew36]

That's great DrByte. How hard would it be to make that work with 1.3.9h?

[DrByte]

I'm guessing it should just work, but I haven't tested it on that old version.

[joew36]

I need some help. The owner wants this running and now. I got the WordPress version up and running on another site but we need it on a Zen Cart site today (tomorrow).

I get an error message from SetaPDF that the source file cannot be found and it downloads a 0 k file.

Any ideas?