PdfTocPlugin.php

<?php
/**
 * PDF ToC
 *
 * Adapted from PDF Text plugin by Roy Rosenzweig Center for History and New Media
 * @license http://www.gnu.org/licenses/gpl-3.0.txt GNU GPLv3
 *
  * This plugin is to be combined with Internet Archive Bookreader plugin
 * to allow table of contents browsing within the viewer.
 *
 * The PDF Text plugin.
 *
 * @package Omeka\Plugins\PdfToc
 */
class PdfTocPlugin extends Omeka_Plugin_AbstractPlugin
{
  const ELEMENT_SET_NAME = 'PDF Table of Contents';
  const ELEMENT_NAME = 'Text';

  protected $_hooks = array(
      'install',
      'uninstall',
      'config_form',
      'config',
      'before_save_file',
      'toc_for_bookreader',
      'toc_for_public_show',
  );

  protected $_pdfMimeTypes = array(
      'application/pdf',
      'application/x-pdf',
      'application/acrobat',
      'text/x-pdf',
      'text/pdf',
      'applications/vnd.pdf',
  );

  /**
   * Install the plugin.
   */
  public function hookInstall()
  {
      // Don't install if the pdftk command doesn't exist.
      // See: http://stackoverflow.com/questions/592620/check-if-a-program-exists-from-a-bash-script
      if ((int) shell_exec('hash pdftk 2>&- || echo -1')) {
          throw new Omeka_Plugin_Installer_Exception(__('The pdftk command-line utility '
          . 'is not installed. pdftk must be installed to install this plugin.'));
      }
      // Don't install if a PDF element set already exists.
      if ($this->_db->getTable('ElementSet')->findByName(self::ELEMENT_SET_NAME)) {
          throw new Omeka_Plugin_Installer_Exception(__('An element set by the name "%s" already '
          . 'exists. You must delete that element set to install this plugin.', self::ELEMENT_SET_NAME));
      }
      insert_element_set(
          array('name' => self::ELEMENT_SET_NAME, 'record_type' => 'File'),
          array(array('name' => self::ELEMENT_NAME))
      );
  }

  /**
   * Uninstall the plugin
   */
  public function hookUninstall()
  {
      // Delete the PDF element set.
      $this->_db->getTable('ElementSet')->findByName(self::ELEMENT_SET_NAME)->delete();
  }


  /**
   * Display the config form.
   */
  public function hookConfigForm()
  {
      echo get_view()->partial(
          'plugins/pdf-toc-config-form.php',
          array('valid_storage_adapter' => $this->isValidStorageAdapter())
      );
  }

  /**
   * Handle the config form.
   */
  public function hookConfig()
  {
      // Run the text extraction process if directed to do so.
      if ($_POST['pdf_toc_process'] && $this->isValidStorageAdapter()) {
          Zend_Registry::get('bootstrap')->getResource('jobs')
              ->sendLongRunning('PdfTocProcess');
      }
  }

  /**
   * Add the PDF text to the file record.
   *
   * This has a secondary effect of including the text in the search index.
   */
  public function hookBeforeSaveFile($args)
  {
      // Extract table of contents only on file insert.
      if (!$args['insert']) {
          return;
      }
      $file = $args['record'];
      // Ignore non-PDF files.
      if (!in_array($file->mime_type, $this->_pdfMimeTypes)) {
          return;
      }
      // Add the PDF toc to the file record.
      $element = $file->getElement(self::ELEMENT_SET_NAME, self::ELEMENT_NAME);
      $toc = $this->pdfToc($file->getPath());
      // pdftoc must return a string to be saved to the element_texts table.
       $file->addTextForElement($element, $toc);

  }

  /**
   * Extract the table of contents from a PDF file.
   *
   * @param string $path
   * @return string
   */
  public function pdfToc($path)
  {
      $path = escapeshellarg($path);
      // dump_data PDFtk parameter encodes non-ASCII charaters as XML numerical entities
      // which are displayed as it stands in the Universal Viewer. e.g PDF bookmark "Scène première"
      // will be displayed as "Sc&#232;ne Premi&#232;re" in the UV index (generated from a JSON file).
      // This problem does not occurs with BookReader which generates its TOC in HTML.
      $dump_data =  shell_exec("pdftk $path dump_data_utf8");

  if (is_string($dump_data)) {
          //prepare Toc. Tested with PDFtk 2.02.
          $dump_data = preg_replace("/^.*(Bookmark.*)$/isU", "$1", $dump_data);
          $dump_data = preg_replace("/BookmarkBegin\n/isU", "", $dump_data);
          $dump_data = preg_replace("/(^.*)PageMediaBegin.*$/isU", "$1", $dump_data);
          $dump_data_array = preg_split("/\n/", $dump_data);

          $toc = "";
          for ($i = 0; $i <= sizeof($dump_data_array); $i+=3)
          {
            // Bookmarks created with Acrobat Pro may contain carriage returns
            // i.e. \r (displayed &#13; when using PDFtk dump_data instead of PDFtk dump_data_utf8).
            $bm_title = str_replace("BookmarkTitle: ", "", preg_replace("/\r/", "", $dump_data_array[$i]));
            // Deletion of spare spaces before and after the titles (e.g. " Le Horla ").
            $bm_title = preg_replace("/ *$/", "", $bm_title);
            $bm_title = preg_replace("/^ */", "", $bm_title);
            $bm_level = str_replace("BookmarkLevel: ", "", $dump_data_array[$i+1]);
            $bm_page = str_replace("BookmarkPageNumber: ", "", $dump_data_array[$i+2]);
            if ($toc != "")
            {
              $toc .= "\n";
            }
            if ( ($bm_level != "") and ($bm_title != "") and ($bm_page != "") )
            {
              $toc .= $bm_level."|".$bm_title."|".$bm_page;
            }
          }
          return $toc;
    }
  }

  /**
   * Determine if the plugin supports the storage adapter.
   *
   *
   * @return bool
   */
  public function isValidStorageAdapter()
  {
      $storageAdapter = Zend_Registry::get('bootstrap')
          ->getResource('storage')->getAdapter();
      if (!($storageAdapter instanceof Omeka_Storage_Adapter_Filesystem)) {
          return false;
      }
      return true;
  }

  /**
   * Get the PDF MIME types.
   *
   * @return array
   */
  public function getPdfMimeTypes()
  {
      return $this->_pdfMimeTypes;
  }

  /**
   * Display Table of Contents for BookReader.
   *
   * @param array $args
   *   Two specific arguments:
   *   - (integer) page: set the page to be shown when including the iframe,
   *   - (boolean) embed_functions: allow user to include an iframe with all
   *   functions (Zoom, Search...). Can be used to include a better viewer
   *   into items/views.php without requiring user to use the full viewer.
   *
   * @return void
   */
  public function hookTocForBookreader($args)
  {
    $args["toc_view"] = 'views' . DIRECTORY_SEPARATOR . 'public'. DIRECTORY_SEPARATOR . 'bookreader_toc.php';
    $this->formatToc($args);
  }

  /**
   * Display Table of Contents for Public show
   *
   * @param array $args
   *   Two specific arguments:
   *   - (integer) page: set the page to be shown when including the iframe,
   *   - (boolean) embed_functions: allow user to include an iframe with all
   *   functions (Zoom, Search...). Can be used to include a better viewer
   *   into items/views.php without requiring user to use the full viewer.
   *
   * @return void
   */
  public function hookTocForPublicShow($args)
  {
    $args["toc_view"] = 'views' . DIRECTORY_SEPARATOR . 'public'. DIRECTORY_SEPARATOR . 'public_toc.php';
    $this->formatToc($args);
  }

  private function formatToc($args)
  {
    $view = $args['view'];
    $item = isset($args['item']) && !empty($args['item'])
    ? $args['item']
    : $view->item;
    $files = $item->getFiles();

    foreach ($files as $file) {
      if (in_array($file->mime_type, $this->_pdfMimeTypes)) {
        $textElement = $file->getElementTexts(
        self::ELEMENT_SET_NAME,
        self::ELEMENT_NAME
        );
        $toc = $textElement[0];
        if (preg_match("/InfoValue/", $toc))
        {
          return;
        }
        $sortie = "";
        $toc = rtrim($toc);
        $tab_toc = preg_split("/\n/", $toc);
        $niveau_pdt = "";
        $total = (count($tab_toc)-1);
        for ($i = 0; $i <= $total; $i++)
        {
          $tab_ligne = preg_split("/\|/", $tab_toc[$i]);

          $niveau = $tab_ligne[0];
          $titre  = $tab_ligne[1];
          $page   = $tab_ligne[2];
          if ($niveau_pdt == "")
          {
            // Première ligne
            $sortie .= "<ul>";
          }
          elseif ($niveau_pdt < $niveau)
          {
            for ($k = $niveau_pdt; $k < $niveau; $k++)
            {
              $sortie .= "<ul>\n";
            }
          }
          elseif ($niveau_pdt > $niveau)
          {
            for ($k = $niveau_pdt; $k > $niveau; $k--)
            {
              $sortie .= "</ul>\n";
            }
          }

          if ($page)
          {
            $sortie .= "<li><a onclick='javascript:br.jumpToIndex(".($page - 1).");return false;' href='".url()."?page=".($page - 1)."#lire-doc'>".$titre."</a></li>\n";
          }
          $niveau_pdt = $niveau;
        }

        $toc = $sortie ;
        include_once $args["toc_view"];
      }
    }
  }
}