gistfile1.aw

<?php

/**
 * @file
 * Input filter which adds or rewrites a title attribute to links. The title
 * is taken form the pagetitle where the link is pointing to.
 *
 * @author Rolf Meijer for Studio Karu
 *   @see http://drupal.org/user/358052
 */
 
/**
 * Implements hook_help().
 */
function linktitle_help($path, $arg) {
  switch ($path) {
    case 'admin/help#linktitle':
      $output = '<p>' . t('To use the Links Title filter, simply enable the'
      . ' Links Title filter for one or more of your'
      . ' <a href="@text_formats">text formats</a>.', array(
        '@text_formats' => url('admin/config/content/formats'))) . '</p><p>';
      $output .= t('If you also enable other filters that act on links make'
      . ' sure that the one that needs to take precedence is the last one'
      . ' called in the Filter processing porder.') . '</p>';
      return $output;
  }
}

/**
 * Implements hook_filter_info().
 */
function linktitle_filter_info() {
  $filters['linktitle'] = array(
    'title' => t('Adds a title attribute to links'),
    'description' => t('Adds a title attribute to links, with it\'s value'
    . ' taken from the pagetitle where the link is pointing to.'),
    'process callback' => '_linktitle_filter_process',
    'settings callback' => '_linktitle_filter_settings',
    'default settings' => array(
      'linktitle_display_tip' => 1,
      'linktitle_maxread_bytes' => 2000,
    ),
    'tips callback' => '_linktitle_filter_tips',
  );
  return $filters;
}


/**
 * Settings callback for the linktitle filter.
 */
function _linktitle_filter_settings($form, &$form_state, $filter, $format, $defaults) {
  $filter->settings += $defaults;

  $settings['linktitle_maxread_bytes'] = array(
    '#type' => 'textfield',
    '#title' => t('Maximum number of bytes read'),
    '#default_value' => $filter->settings['linktitle_maxread_bytes'],
    '#maxlength' => 8,
    '#description' => t('Number of bytes read from the page that is linked to.'
    . ' The title-tag should be in those read bytes,'
    . ' if you miss a title from a page,'
    . ' it is possible that the title tag is after those read bytes.'
    . ' In that case increase this number.'),
  );
  return $settings;
}


/**
 * Filter process callback for linktitle filter.
 *
 * @param $text
 *   Text to be filtered. Regex pattern matches links to be processed.
 *
 * @return
 *   Filtered text with processed links including HTML title attributes
 */
function _linktitle_filter_process($text, $filter) {
  // Match on the url in the link tag
  $pattern = '%<a([^>]*?href="([^"]+?)"[^>]*?)>%i';
  $maxread = $filter->settings['linktitle_maxread_bytes'];
  
  function _process_text($matches) {
      if (strpos($matches[1], 'title=') == FALSE) {
	$pagetitle = check_plain(get_remotetitle($matches[2], $maxread));
	return substr_replace($matches[0], 'title='.$insert_title, -1, -1);
      } else {
	return $matches[0];
      }
  }
  $replacement = preg_replace_callback($pattern,'_process_text', $text);
  return $replacement;
}

function get_remotetitle($url, $bytes = 5000)
{
  // Init
  $dat = ''; $fp = fopen($url,"r");
  if ($fp) {
    $dat = fread($fp, $bytes);
    fclose($fp);
  }
  if (preg_match('|<title>[[:space:]]*(.*)[[:space:]]*</title>|Uis', $dat, $match )) {
    $dat = $match[1];
  }
  else {
    $dat = '';
  }
  return $dat;
}

/**
 * Filter tips callback for linktitle filter.
 */
function _linktitle_filter_tips($filter, $format, $long = FALSE) {
  if ($filter->settings['linktitle_display_tip']) {
    return t('Adds a title attribute to links found in the content');
  }
}