Drupal add graph metatags with preprocess_html

drupal.metatags_preprocess_html.php

/**
 * Implements hook_preprocess_html()
 *
 * Adds open graph tags
 *
 * @param array $variables
 */
function module_preprocess_html(&$variables) {

  /*
   * Init Metatags
   * Don't need to do this on admin pages
   */

  //Fetch node
  if(!path_is_admin(current_path())) {
    $node = menu_get_object();

    $meta = array();

    /**
     * Title
     *
     * Use site name for homepage
     * Use default page title or node title
     */

    if ( drupal_is_front_page() ) {
      $meta['title'] = trim(variable_get('site_name'));
    }
    else {

      //Get drupal title (views pages, node title)
      $meta['title'] = drupal_get_title();

      //Fallback to node title (needed if node title is hidden)
      if(empty($meta['title'])) {
        $meta['title'] = trim($node->title);
      }
    }


    /**
     * Url
     */
    $meta['url'] = url(current_path(), array('absolute' => TRUE));


    /**
     * Site name
     */
    $meta['site_name'] = trim(variable_get('site_name'));


    /**
     * Description
     *
     * Add tokens to $content_tokens in the order that you want them
     * to be checked.  The first token that returns a result will be
     * used.
     *
     */

    //Set default
    $raw_description = variable_get('site_slogan');

    //Tokens to check.  Given in order
    $content_tokens = array(
      '[node:metatag:description]',
      '[node:field-content:summary]',
      '[node:field_content]',
    );

    //Check tokens.  Break at first token find
    foreach ($content_tokens as $token) {
      $token_value = token_replace($token, array('node' => $node), array('clear' => true));
      if($token_value) {
        $raw_description = $token_value;
        break;
      }
    }

    //Set value
    //trim to 100 words
    //strip html
    //trim white space
    //remove line breaks
    $meta['description'] = str_replace(array("\r", "\r\n", "\n"), '', trim(dnv_custom_limit_words(strip_tags($raw_description),100)));


    /**
     * Image
     *
     * Add tokens to $image_tokens in the order that you want them
     * to be checked.  The first token that returns a result will be
     * used.
     *
     */

    //Set default
    $image_path = '';

    //Tokens to check.  Given in order
    $image_tokens = array(
      '[node:field-neighbourhood-map:file:url]',
      '[node:field-banner:0:field-banner-image:file:url]',
    );

    //Check tokens.  Break at first token find
    foreach ($image_tokens as $token) {
      $token_value = token_replace($token, array('node' => $node), array('clear' => true));
      if($token_value) {
        $image_path = $token_value;
        break;
      }
    }

    //Set value
    $meta['image'] = $image_path;


    /**
     * Print open graph tags
     */

    $open_graph_attributes = array('title', 'site_name', 'url', 'description', 'image');

    foreach ( $meta as $tag => $value ) {
      if ( $value && in_array($tag, $open_graph_attributes) ) {
        drupal_add_html_head(array(
          '#tag' => 'meta',
          '#attributes' => array(
            'property' => 'og:'.$tag,
            'content' => $value,
          ),
        ), 'og_'.$tag);
      }
    }


    /**
     * Print Twitter card stuff
     */

    $twitter_card_attributes = array('title', 'description', 'image', 'url');

    drupal_add_html_head(array(
      '#tag' => 'meta',
      '#attributes' => array(
        'name' => 'twitter:card',
        'content' => 'summary',
      ),
    ), 'twitter_card');

    foreach ( $meta as $tag => $value ) {
      if ( $value && in_array($tag, $twitter_card_attributes) ) {
        drupal_add_html_head(array(
          '#tag' => 'meta',
          '#attributes' => array(
            'name' => 'twitter:'.$tag,
            'content' => $value,
          ),
        ), 'twitter_'.$tag);
      }
    }

    /*
     * End of Metatags
     */
  }
}