PBCoreElementSetPlugin.php

<?php
/**
 * PBCore Element Set plugin
 *
 * Creates element set for PBCore (Public Broadcasting Metadata Dictionary), a
 * standard for digitalized documents (see http://pbcore.org).
 *
 * @copyright Pop Up Archive, 2012
 * @license http://www.gnu.org/licenses/gpl-3.0.txt
 */

/**
 * The PBCore Element Set plugin.
 * @package Omeka\Plugins\PBCoreElementSet
 */
class PBCoreElementSetPlugin extends Omeka_Plugin_AbstractPlugin
{
    private $_elementSetName = 'PBCore';

    /**
     * @var array Hooks for the plugin.
     */
    protected $_hooks = array(
        'install',
        'uninstall',
        'config_form',
        'config',
        'after_save_item',
        'public_theme_header',
        // BeamMeUpToInternetArchive hook used to get list of metadata.
        'beamia_set_settings',
    );

    /**
     * @var array Filters for the plugin.
     */
    protected $_filters = array(
        'response_contexts',
        'action_contexts',
    );

    /**
     * @var array This plugin's options.
     */
    protected $_options = array(
        'pbcore_element_set_add_url_as_identifier' => false,
    );

    /**
     * Install the plugin.
     */
    public function hookInstall()
    {
        $this->_installOptions();

        // Load elements to add.
        require_once('elements.php');

        // Don't install if an element set already exists.
        if ($this->_getElementSet($this->_elementSetName)) {
            throw new Omeka_Plugin_Installer_Exception('An element set by the name "' . $this->_elementSetName . '" already exists. You must delete that element set to install this plugin.');
        }

        insert_element_set($elementSetMetadata, $elements);
    }

    /**
     * Uninstall the plugin.
     */
    public function hookUninstall()
    {
        $this->_deleteElementSet($this->_elementSetName);

        $this->_uninstallOptions();
    }

    /**
     * Displays configuration form.
     *
     * @return void
     */
    public function hookConfigForm()
    {
        include('config_form.php');
    }

    /**
     * Saves plugin configuration.
     *
     * @return void
     */
    public function hookConfig($args)
    {
        $post = $args['post'];

        set_option('pbcore_element_set_add_url_as_identifier', $post['PBCoreElementSetAddUrlAsIdentifier']);
    }

    /**
     * The recommended pbcore identifier is to use the omeka url with current
     * id, so we need to update the item once it is saved for the first time
     * (insert). An option is added to disable this feature.
     */
    public function hookAfterSaveItem($args)
    {
        $post = $args['post'];
        $item = $args['record'];

        // Add the default identifier if wished.
        if ($args['insert'] && (boolean) get_option('pbcore_element_set_add_url_as_identifier')) {
            $text = WEB_ROOT . '/items/show/' . $item->id;

            // Check if this url already exists as an identifier.
            $elementTexts = $item->getElementTexts('PBCore', 'Identifier');
            foreach ($elementTexts as $key => $elementText) {
                $elementTexts[$key] = $elementText->text;
            }
            if (!in_array($text, $elementTexts)) {
                //// We use direct sql to avoid some problems with this update, in
                //// particular when there are attached files.
                // $elementTexts = array($this->_elementSetName => array('Identifier' => array(array(
                //     'text' => $text,
                //     'html' => false,
                // ))));
                // update_item($item, array(), $elementTexts);
                static $elementId;
                if (!$elementId) {
                    $elementId = $this->_db->getTable('Element')->findByElementSetNameAndElementName('PBCore', 'Identifier')->id;
                }
                $sql = "
                    INSERT INTO {$this->_db->ElementText} (record_id, record_type, element_id, html, text)
                    VALUES ('{$item->id}', 'Item', '{$elementId}', '0', '$text')
                ";
                $this->_db->query($sql);
            }
        }
        // Update or remove (see status).
        else {
            // Nothing, because the user should be able to remove or update the
            // default identifier manually.
        }
    }

    // TODO To check.
    public function hookPublicThemeHeader()
    {
        $request = Zend_Controller_Front::getInstance()->getRequest();
        if ($request->getControllerName() == 'items' && $request->getActionName() == 'show') {
            echo '<link rel="alternate" type="application/rss+xml" href="' . record_url(get_current_record('item')) . '?output=pbcore" id="pbcore"/>' . PHP_EOL;
        }
        if ($request->getControllerName() == 'items' && $request->getActionName() == 'browse') {
            echo '<link rel="alternate" type="application/rss+xml" href="' . record_url(get_current_record('item')) . '?output=pbcore" id="pbcore"/>' . PHP_EOL;
        }
    }

    /**
     * BeamMeUpToInternetArchive hook used to get list of metadata.
     *
     * Note that default Dublin Core metadata are removed.
     */
    public function hookBeamiaSetSettings($args)
    {
        // Don't use Dublin Core metadata that are created by default.
        $settings = array();
        $record = $args['record'];
        $elementSetName = $this->_elementSetName;

        // Add existing elements.
        $options = array(
            'show_empty_elements' => false,
            'return_type' => 'array',
        );
        if ($elementSetName) {
            $options['show_element_sets'] = $elementSetName;
        }
        $elementTexts = all_element_texts($record, $options);

        // Don't add "Dublin Core" in the header, because this is the standard
        // on Internet Archive.
        $cleanElementSetName = ($elementSetName == 'Dublin Core') ?
            '' :
            preg_replace('#[^a-z0-9]+#', '-', strtolower($elementSetName)) . '-';

        foreach ($elementTexts[$elementSetName] as $element => $texts) {
            // Replace unique or serie of non-alphanumeric character by "-".
            $meta = preg_replace('#[^a-z0-9]+#', '-', strtolower($element));
            foreach ($texts as $key => $text) {
                $base = (count($texts) == 1) ?
                    'x-archive-meta-' :
                    'x-archive-meta' . sprintf('%02d', $key) . '-';
                $settings[] = $base . $cleanElementSetName . $meta . ':' . $text;
            }

            // Add default title if it exists. If none, a generic name will be
            // added automatically.
            if ($element == 'Title') {
                $settings[] = 'x-archive-meta-title:' . $texts[0];
            }
        }

        $args['settings'] = $settings;
    }

    public function filterResponseContexts($contexts)
    {
        $contexts['pbcore'] = array(
            'suffix'  => 'pbcore',
            'headers' => array('Content-Type' => 'text/xml'),
        );

        return $contexts;
    }

    public function filterActionContexts($contexts, $controller)
    {
        if ($controller['controller'] instanceof ItemsController) {
            $contexts['show'][] = 'pbcore';
            $contexts['browse'][] = 'pbcore';
        }

        return $contexts;
    }

    private function _getElementSet($elementSetName)
    {
        return $this->_db
            ->getTable('ElementSet')
            ->findByName($elementSetName);
    }

    private function _deleteElementSet($elementSetName)
    {
        $elementSet = $this->_getElementSet($elementSetName);

        if ($elementSet) {
            $elements = $elementSet->getElements();
            foreach ($elements as $element) {
                $element->delete();
            }
            $elementSet->delete();
        }
    }
}