aggregator.module

<?php
// $Id$

/**
 * @file
 * Used to aggregate syndicated content (RSS and RDF).
 */

/**
 * Implementation of hook_help().
 */
function aggregator_help($section) {
  switch ($section) {
    case 'admin/help#aggregator':
      $output = '<p>'. t('The news aggregator is a powerful on-site RSS syndicator/news reader that can gather fresh content from news sites and weblogs around the web.') .'</p>';
      $output .= '<p>'. t('Users can view the latest news chronologically in the <a href="%aggregator">main news aggregator display</a> or by <a href="%aggregator-sources">source</a>. Administrators can add, edit and delete feeds and choose how often to check for newly updated news for each individual feed. Administrators can also tag individual feeds with categories, offering selective grouping of some feeds into separate displays. Listings of the latest news for individual sources or categorized sources can be enabled as blocks for display in the sidebar through the <a href="%admin-block">block administration page</a>. The news aggregator requires cron to check for the latest news from the sites to which you have subscribed. Drupal also provides a <a href="%aggregator-opml">machine-readable OPML file</a> of all of your subscribed feeds.', array('%aggregator' => url('aggregator'), '%aggregator-sources' => url('aggregator/sources'), '%admin-block' => url('admin/block'), '%aggregator-opml' => url('aggregator/opml'))) .'</p>';
      $output .= t('<p>You can</p>
<ul>
<li>administer your list of news feeds <a href="%admin-aggregator">administer &gt;&gt;  aggregator</a>.</li>
<li>add a new feed <a href="%admin-aggregator-add-feed">administer &gt;&gt; aggregator &gt;&gt; add feed</a>.</li>
<li>add a new category <a href="%admin-aggregator-add-category">administer &gt;&gt; aggregator &gt;&gt; add category</a>.</li>
<li>configure global settings for the news aggregator <a href="%admin-settings-aggregator">administer &gt;&gt; settings &gt;&gt; aggregator</a>.</li>
<li>control access to the aggregator module through access permissions <a href="%admin-access">administer &gt;&gt; access control &gt;&gt; permissions</a>.</li>
<li>set permissions to access new feeds for user roles such as anonymous users at <a href="%admin-access">administer &gt;&gt; access control</a>.</li>
<li>view the <a href="%aggregator">aggregator page</a>.</li>
</ul>
', array('%admin-aggregator' => url('admin/aggregator'), '%admin-aggregator-add-feed' => url('admin/aggregator/add/feed'), '%admin-aggregator-add-category' => url('admin/aggregator/add/category'), '%admin-settings-aggregator' => url('admin/settings/aggregator'), '%admin-access' => url('admin/access'), '%aggregator' => url('aggregator')));
      $output .= '<p>'. t('For more information please read the configuration and customization handbook <a href="%aggregator">Aggregator page</a>.', array('%aggregator' => 'http://www.drupal.org/handbook/modules/aggregator/')) .'</p>';
      return $output;
    case 'admin/modules#description':
      return t('Aggregates syndicated content (RSS and RDF feeds).');
    case 'admin/aggregator':
      return t('<p>Thousands of sites (particularly news sites and weblogs) publish their latest headlines and/or stories in a machine-readable format so that other sites can easily link to them. This content is usually in the form of an <a href="http://blogs.law.harvard.edu/tech/rss">RSS</a> feed (which is an XML-based syndication standard). To display the feed or category in a block you must decide how many items to show by editing the feed or block and turning on the <a href="%block">feed\'s block</a>.</p>', array('%block' => url('admin/block')));
    case 'admin/aggregator/add/feed':
      return t('<p>Add a site that has an RSS/RDF feed. The URL is the full path to the RSS feed file. For the feed to update automatically you must run "cron.php" on a regular basis. If you already have a feed with the URL you are planning to use, the system will not accept another feed with the same URL.</p>');
    case 'admin/aggregator/add/category':
      return t('<p>Categories provide a way to group items from different news feeds together. Each news category has its own feed page and block. For example, you could tag various sport-related feeds as belonging to a category called <em>Sports</em>. News items can be added to a category automatically by setting a feed to automatically place its item into that category, or by using the categorize items link in any listing of news items.</p>');
  }
}

function aggregator_settings() {
  $items = array(0 => t('none')) + drupal_map_assoc(array(3, 5, 10, 15, 20, 25), '_aggregator_items');
  $period = drupal_map_assoc(array(3600, 10800, 21600, 32400, 43200, 86400, 172800, 259200, 604800, 1209600, 2419200, 4838400, 9676800), 'format_interval');

  $form['aggregator_allowed_html_tags'] = array(
    '#type' => 'textfield', '#title' => t('Allowed HTML tags'), '#size' => 80, '#maxlength' => 255,
    '#default_value' => variable_get('aggregator_allowed_html_tags', '<a> <b> <br> <dd> <dl> <dt> <em> <i> <li> <ol> <p> <strong> <u> <ul>'),
    '#description' => t('The list of tags which are allowed in feeds, i.e., which will not be removed by Drupal.')
  );

  $form['aggregator_summary_items'] = array(
    '#type' => 'select', '#title' => t('Items shown in sources and categories pages') ,
    '#default_value' => variable_get('aggregator_summary_items', 3), '#options' => $items,
    '#description' =>  t('The number of items which will be shown with each feed or category in the feed and category summary pages.')
  );

  $form['aggregator_clear'] = array(
    '#type' => 'select', '#title' => t('Discard news items older than'),
    '#default_value' => variable_get('aggregator_clear', 9676800), '#options' => $period,
    '#description' => t('Older news items will be automatically discarded.  Requires crontab.')
  );

  $form['aggregator_category_selector'] = array(
    '#type' => 'radios', '#title' => t('Category selection type'), '#default_value' => variable_get('aggregator_category_selector', 'check'),
    '#options' => array('check' => t('checkboxes'), 'select' => t('multiple selector')),
    '#description' => t('The type of category selection widget which is shown on categorization pages. Checkboxes are easier to use; a multiple selector is good for working with large numbers of categories.')
  );
  return $form;
}

/**
 * Helper function for drupal_map_assoc.
 */
function _aggregator_items($count) {
  return format_plural($count, '1 item', '%count items');
}

/**
 * Implementation of hook_perm().
 */
function aggregator_perm() {
  return array('administer news feeds', 'access news feeds');
}

/**
 * Implementation of hook_menu().
 */
function aggregator_menu($may_cache) {
  $items = array();
  $edit = user_access('administer news feeds');
  $view = user_access('access news feeds');

  if ($may_cache) {
    $items[] = array('path' => 'admin/aggregator', 'title' => t('aggregator'),
      'callback' => 'aggregator_admin_overview', 'access' => $edit);
    $items[] = array('path' => 'admin/aggregator/edit/feed', 'title' => t('edit feed'),
      'callback' => 'aggregator_admin_edit_feed', 'access' => $edit,
      'type' => MENU_CALLBACK);
    $items[] = array('path' => 'admin/aggregator/edit/category', 'title' => t('edit category'),
      'callback' => 'aggregator_admin_edit_category', 'access' => $edit,
      'type' => MENU_CALLBACK);
    $items[] = array('path' => 'admin/aggregator/remove', 'title' => t('remove items'),
      'callback' => 'aggregator_admin_remove_feed', 'access' => $edit,
      'type' => MENU_CALLBACK);
    $items[] = array('path' => 'admin/aggregator/update', 'title' => t('update items'),
      'callback' => 'aggregator_admin_refresh_feed', 'access' => $edit,
      'type' => MENU_CALLBACK);

    $items[] = array('path' => 'admin/aggregator/list', 'title' => t('list'),
      'type' => MENU_DEFAULT_LOCAL_TASK, 'weight' => -10);
    $items[] = array('path' => 'admin/aggregator/add/feed', 'title' => t('add feed'),
      'callback' => 'aggregator_admin_edit_feed', 'access' => $edit,
      'type' => MENU_LOCAL_TASK);
    $items[] = array('path' => 'admin/aggregator/add/category', 'title' => t('add category'),
      'callback' => 'aggregator_admin_edit_category', 'access' => $edit,
      'type' => MENU_LOCAL_TASK);

    $items[] = array('path' => 'aggregator', 'title' => t('news aggregator'),
      'callback' => 'aggregator_page_last', 'access' => $view,
      'weight' => 5);
    $items[] = array('path' => 'aggregator/sources', 'title' => t('sources'),
      'callback' => 'aggregator_page_sources', 'access' => $view);
    $items[] = array('path' => 'aggregator/categories', 'title' => t('categories'),
      'callback' => 'aggregator_page_categories', 'access' => $view,
      'type' => MENU_ITEM_GROUPING);
    $items[] = array('path' => 'aggregator/rss', 'title' => t('RSS feed'),
      'callback' => 'aggregator_page_rss', 'access' => $view,
      'type' => MENU_CALLBACK);
    $items[] = array('path' => 'aggregator/opml', 'title' => t('OPML feed'),
      'callback' => 'aggregator_page_opml', 'access' => $view,
      'type' => MENU_CALLBACK);
  }
  else {
    if (arg(0) == 'aggregator' && is_numeric(arg(2))) {
      if (arg(1) == 'sources') {
        $feed = db_fetch_object(db_query('SELECT title, fid FROM {aggregator_feed} WHERE fid = %d', arg(2)));
        if ($feed) {
          $items[] = array('path' => 'aggregator/sources/'. $feed->fid, 'title' => $feed->title,
                           'callback' => 'aggregator_page_source', 'access' => $view);
          $items[] = array('path' => 'aggregator/sources/'. $feed->fid .'/view', 'title' => t('view'),
                           'type' => MENU_DEFAULT_LOCAL_TASK, 'weight' => -10);
          $items[] = array('path' => 'aggregator/sources/'. $feed->fid .'/categorize', 'title' => t('categorize'),
                           'callback' => 'aggregator_page_source', 'access' => $edit,
                           'type' => MENU_LOCAL_TASK);
          $items[] = array('path' => 'aggregator/sources/'. $feed->fid .'/configure', 'title' => t('configure'),
                           'callback' => 'aggregator_edit', 'access' => $edit,
                           'type' => MENU_LOCAL_TASK,
                           'weight' => 1);
        }
      }
      else if (arg(1) == 'categories') {
        $category = db_fetch_object(db_query('SELECT title, cid FROM {aggregator_category} WHERE cid = %d', arg(2)));
        if ($category) {
          $items[] = array('path' => 'aggregator/categories/'. $category->cid, 'title' => $category->title,
                           'callback' => 'aggregator_page_category', 'access' => $view);
          $items[] = array('path' => 'aggregator/categories/'. $category->cid .'/view', 'title' => t('view'),
                           'type' => MENU_DEFAULT_LOCAL_TASK, 'weight' => -10);
          $items[] = array('path' => 'aggregator/categories/'. $category->cid .'/categorize', 'title' => t('categorize'),
                           'callback' => 'aggregator_page_category', 'access' => $edit,
                           'type' => MENU_LOCAL_TASK);
          $items[] = array('path' => 'aggregator/categories/'. $category->cid .'/configure', 'title' => t('configure'),
                           'callback' => 'aggregator_edit', 'access' => $edit,
                           'type' => MENU_LOCAL_TASK,
                           'weight' => 1);
        }
      }
    }
  }

  return $items;
}

/**
 * Implementation of hook_cron().
 *
 * Checks news feeds for updates once their refresh interval has elapsed.
 */
function aggregator_cron() {
  $result = db_query('SELECT * FROM {aggregator_feed} WHERE checked + refresh < %d', time());
  while ($feed = db_fetch_array($result)) {
    aggregator_refresh($feed);
  }
}

/**
 * Implementation of hook_block().
 *
 * Generates blocks for the latest news items in each category and feed.
 */
function aggregator_block($op, $delta = 0, $edit = array()) {
  if (user_access('access news feeds')) {
    if ($op == 'list') {
      $result = db_query('SELECT cid, title FROM {aggregator_category} ORDER BY title');
      while ($category = db_fetch_object($result)) {
        $block['category-'. $category->cid]['info'] = t('%title category latest items', array('%title' => theme('placeholder', $category->title)));
      }
      $result = db_query('SELECT fid, title FROM {aggregator_feed} ORDER BY fid');
      while ($feed = db_fetch_object($result)) {
        $block['feed-'. $feed->fid]['info'] = t('%title feed latest items', array('%title' => theme('placeholder', $feed->title)));
      }
    }
    else if ($op == 'configure') {
      list($type, $id) = explode('-', $delta);
      if ($type == 'category') {
        $value = db_result(db_query('SELECT block FROM {aggregator_category} WHERE cid = %d', $id));
      }
      else {
        $value = db_result(db_query('SELECT block FROM {aggregator_feed} WHERE fid = %d', $id));
      }
      $form['block'] = array('#type' => 'select', '#title' => t('Number of news items in block'), '#default_value' => $value, '#options' => drupal_map_assoc(array(2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)));
      return $form;
    }
    else if ($op == 'save') {
      list($type, $id) = explode('-', $delta);
      if ($type == 'category') {
        $value = db_query('UPDATE {aggregator_category} SET block = %d WHERE cid = %d', $edit['block'], $id);
      }
      else {
        $value = db_query('UPDATE {aggregator_feed} SET block = %d WHERE fid = %d', $edit['block'], $id);
      }
    }
    else if ($op == 'view') {
      list($type, $id) = explode('-', $delta);
      switch ($type) {
        case 'feed':
          if ($feed = db_fetch_object(db_query('SELECT fid, title, block FROM {aggregator_feed} WHERE fid = %d', $id))) {
            $block['subject'] = check_plain($feed->title);
            $result = db_query_range('SELECT * FROM {aggregator_item} WHERE fid = %d ORDER BY timestamp DESC, iid DESC', $feed->fid, 0, $feed->block);
            $block['content'] = '<div class="more-link">'. l(t('more'), 'aggregator/sources/'. $feed->fid, array('title' => t('View this feed\'s recent news.'))) .'</div>';
          }
          break;

        case 'category':
          if ($category = db_fetch_object(db_query('SELECT cid, title, block FROM {aggregator_category} WHERE cid = %d', $id))) {
            $block['subject'] = check_plain($category->title);
            $result = db_query_range('SELECT i.* FROM {aggregator_category_item} ci LEFT JOIN {aggregator_item} i ON ci.iid = i.iid WHERE ci.cid = %d ORDER BY i.timestamp DESC, i.iid DESC', $category->cid, 0, $category->block);
            $block['content'] = '<div class="more-link">'. l(t('more'), 'aggregator/categories/'. $category->cid, array('title' => t('View this category\'s recent news.'))) .'</div>';
          }
          break;
      }
      $items = array();
      while ($item = db_fetch_object($result)) {
        $items[] = theme('aggregator_block_item', $item);
      }
      $block['content'] = theme('item_list', $items) . $block['content'];
    }
    return $block;
  }
}

function aggregator_remove($feed) {
  $result = db_query('SELECT iid FROM {aggregator_item} WHERE fid = %d', $feed['fid']);
  while ($item = db_fetch_object($result)) {
    $items[] = "iid = $item->iid";
  }
  if ($items) {
    db_query('DELETE FROM {aggregator_category_item} WHERE '. implode(' OR ', $items));
  }
  db_query('DELETE FROM {aggregator_item} WHERE fid = %d', $feed['fid']);
  db_query("UPDATE {aggregator_feed} SET checked = 0, etag = '', modified = 0 WHERE fid = %d", $feed['fid']);
  drupal_set_message(t('The news items from %site have been removed.', array('%site' => theme('placeholder', $feed['title']))));
}

/**
 * Call-back function used by the XML parser.
 */
function aggregator_element_start($parser, $name, $attributes) {
  global $item, $element, $tag, $items, $channel;

  switch ($name) {
    case 'IMAGE':
    case 'TEXTINPUT':
    case 'CONTENT':
    case 'SUMMARY':
    case 'TAGLINE':
    case 'SUBTITLE':
    case 'LOGO':
    case 'INFO':
      $element = $name;
      break;
    case 'ID':
      if ($element != 'ITEM') {
        $element = $name;
      }
    case 'LINK':
      if ($attributes['REL'] == 'alternate') {
        if ($element == 'ITEM') {
          $items[$item]['LINK'] = $attributes['HREF'];
        }
        else {
          $channel['LINK'] = $attributes['HREF'];
        }
      }
      break;
    case 'ITEM':
      $element = $name;
      $item += 1;
      break;
    case 'ENTRY':
      $element = 'ITEM';
      $item += 1;
      break;
  }

  $tag = $name;
}

/**
 * Call-back function used by the XML parser.
 */
function aggregator_element_end($parser, $name) {
  global $element;

  switch ($name) {
    case 'IMAGE':
    case 'TEXTINPUT':
    case 'ITEM':
    case 'ENTRY':
    case 'CONTENT':
    case 'INFO':
      $element = '';
      break;
    case 'ID':
      if ($element == 'ID') {
      $element = '';
  }
}
}

/**
 * Call-back function used by the XML parser.
 */
function aggregator_element_data($parser, $data) {
  global $channel, $element, $items, $item, $image, $tag;

  switch ($element) {
    case 'ITEM':
      $items[$item][$tag] .= $data;
      break;
    case 'IMAGE':
    case 'LOGO':
      $image[$tag] .= $data;
      break;
    case 'LINK':
      if ($data) {
        $items[$item][$tag] .= $data;
      }
      break;
    case 'CONTENT':
      $items[$item]['CONTENT'] .= $data;
      break;
    case 'SUMMARY':
      $items[$item]['SUMMARY'] .= $data;
      break;
    case 'TAGLINE':
    case 'SUBTITLE':
      $channel['DESCRIPTION'] .= $data;
      break;
    case 'INFO':
    case 'ID':
    case 'TEXTINPUT':
      // The sub-element is not supported. However, we must recognize
      // it or its contents will end up in the item array.
      break;
    default:
      $channel[$tag] .= $data;
  }
}

/**
 * Checks a news feed for new items.
 */
function aggregator_refresh($feed) {
  global $channel, $image;

  // Generate conditional GET headers.
  $headers = array();
  if ($feed['etag']) {
    $headers['If-None-Match'] = $feed['etag'];
  }
  if ($feed['modified']) {
    $headers['If-Modified-Since'] = gmdate('D, d M Y H:i:s', $feed['modified']) .' GMT';
  }

  // Request feed.
  $result = drupal_http_request($feed['url'], $headers);

  // Process HTTP response code.
  switch ($result->code) {
    case 304:
      db_query('UPDATE {aggregator_feed} SET checked = %d WHERE fid = %d', time(), $feed['fid']);
      drupal_set_message(t('There is no new syndicated content from %site.', array('%site' => theme('placeholder', $feed['title']))));
      break;
    case 301:
      $feed['url'] = $result->redirect_url;
      watchdog('aggregator', t('Updated URL for feed %title to %url.', array('%title' => theme('placeholder', $feed['title']), '%url' => theme('placeholder', $feed['url']))));
      break;

    case 200:
    case 302:
    case 307:
      // Filter the input data:
     if (aggregator_parse_feed($result->data, $feed)) {

        if ($result->headers['Last-Modified']) {
          $modified = strtotime($result->headers['Last-Modified']);
        }

        /*
        ** Prepare the channel data:
        */

        foreach ($channel as $key => $value) {
          $channel[$key] = trim(strip_tags($value));
        }

        /*
        ** Prepare the image data (if any):
        */

        foreach ($image as $key => $value) {
          $image[$key] = trim($value);
        }

        if ($image['LINK'] && $image['URL'] && $image['TITLE']) {
          $image = '<a href="'. $image['LINK'] .'"><img src="'. $image['URL'] .'" alt="'. $image['TITLE'] .'" /></a>';
        }
        else {
          $image = NULL;
        }

        /*
        ** Update the feed data:
        */

        db_query("UPDATE {aggregator_feed} SET url = '%s', checked = %d, link = '%s', description = '%s', image = '%s', etag = '%s', modified = %d WHERE fid = %d", $feed['url'], time(), $channel['LINK'], $channel['DESCRIPTION'], $image, $result->headers['ETag'], $modified, $feed['fid']);

        /*
        ** Clear the cache:
        */

        cache_clear_all();

        watchdog('aggregator', t('There is new syndicated content from %site.', array('%site' => theme('placeholder', $feed['#title']))));
        drupal_set_message(t('There is new syndicated content from %site.', array('%site' => theme('placeholder', $feed['#title']))));
      }
      break;
    default:
      watchdog('aggregator', t('The RSS-feed from %site seems to be broken, due to "%error".', array('%site' => theme('placeholder', $feed['title']), '%error' => theme('placeholder', $result->code .' '. $result->error))), WATCHDOG_WARNING);
      drupal_set_message(t('The RSS-feed from %site seems to be broken, because of error "%error".', array('%site' => theme('placeholder', $feed['title']), '%error' => theme('placeholder', $result->code .' '. $result->error))));
  }
}

/**
 * Parse the W3C date/time format, a subset of ISO 8601. PHP date parsing
 * functions do not handle this format.
 * See http://www.w3.org/TR/NOTE-datetime for more information.
 * Originally from MagpieRSS (http://magpierss.sourceforge.net/).
 *
 * @param $date_str A string with a potentially W3C DTF date.
 * @return A timestamp if parsed successfully or -1 if not.
 */
function aggregator_parse_w3cdtf($date_str) {
  if (preg_match('/(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})(:(\d{2}))?(?:([-+])(\d{2}):?(\d{2})|(Z))?/', $date_str, $match)) {
    list($year, $month, $day, $hours, $minutes, $seconds) = array($match[1], $match[2], $match[3], $match[4], $match[5], $match[6]);
    // calc epoch for current date assuming GMT
    $epoch = gmmktime($hours, $minutes, $seconds, $month, $day, $year);
    if ($match[10] != 'Z') { // Z is zulu time, aka GMT
      list($tz_mod, $tz_hour, $tz_min) = array($match[8], $match[9], $match[10]);
      // zero out the variables
      if (!$tz_hour) {
        $tz_hour = 0;
      }
      if (!$tz_min) {
        $tz_min = 0;
      }
      $offset_secs = (($tz_hour * 60) + $tz_min) * 60;
      // is timezone ahead of GMT?  then subtract offset
      if ($tz_mod == '+') {
        $offset_secs *= -1;
      }
      $epoch += $offset_secs;
    }
    return $epoch;
  }
  else {
    return FALSE;
  }
}

function aggregator_parse_feed(&$data, $feed) {
  global $items, $image, $channel;

  // Unset the global variables before we use them:
  unset($GLOBALS['element'], $GLOBALS['item'], $GLOBALS['tag']);
  $items = array();
  $image = array();
  $channel = array();

  // parse the data:
  $xml_parser = drupal_xml_parser_create($data);
  xml_set_element_handler($xml_parser, 'aggregator_element_start', 'aggregator_element_end');
  xml_set_character_data_handler($xml_parser, 'aggregator_element_data');

  if (!xml_parse($xml_parser, $data, 1)) {
    watchdog('aggregator', t('The RSS-feed from %site seems to be broken, due to an error "%error" on line %line.', array('%site' => theme('placeholder', $feed['title']), '%error' => xml_error_string(xml_get_error_code($xml_parser)), '%line' => xml_get_current_line_number($xml_parser))), WATCHDOG_WARNING);
    drupal_set_message(t('The RSS-feed from %site seems to be broken, because of error "%error" on line %line.', array('%site' => theme('placeholder', $feed['title']), '%error' => xml_error_string(xml_get_error_code($xml_parser)), '%line' => xml_get_current_line_number($xml_parser))), 'error');
    return 0;
  }
  xml_parser_free($xml_parser);

  /*
  ** We reverse the array such that we store the first item last,
  ** and the last item first.  In the database, the newest item
  ** should be at the top.
  */

  $items = array_reverse($items);

  foreach ($items as $item) {
    unset($title, $link, $author, $description);

    // Prepare the item:
    foreach ($item as $key => $value) {
      $value = decode_entities(trim($value));
      $value = strip_tags($value, variable_get('aggregator_allowed_html_tags', '<a> <b> <br> <dd> <dl> <dt> <em> <i> <li> <ol> <p> <strong> <u> <ul>'));
      $value = filter_xss($value);
      $item[$key] = $value;
    }

    /*
    ** Resolve the item's title.  If no title is found, we use
    ** up to 40 characters of the description ending at a word
    ** boundary but not splitting potential entities.
    */

    if ($item['TITLE']) {
      $title = $item['TITLE'];
    }
    else {
      $title = preg_replace('/^(.*)[^\w;&].*?$/', "\\1", truncate_utf8($item['DESCRIPTION'], 40));
    }

    /*
    ** Resolve the items link.
    */

    if ($item['LINK']) {
      $link = $item['LINK'];
    }
    elseif ($item['GUID'] && (strncmp($item['GUID'], 'http://', 7) == 0)) {
      $link = $item['GUID'];
    }
    else {
      $link = $feed['link'];
    }

    /**
     * Atom feeds have a CONTENT and/or SUMMARY tag instead of a DESCRIPTION tag
     */
    if ($item['CONTENT']) {
      $item['DESCRIPTION'] = $item['CONTENT'];
    }
    else if ($item['SUMMARY']) {
      $item['DESCRIPTION'] = $item['SUMMARY'];
    }

    /*
    ** Try to resolve and parse the item's publication date.  If no
    ** date is found, we use the current date instead.
    */

    if ($item['PUBDATE']) $date = $item['PUBDATE'];                        // RSS 2.0
    else if ($item['DC:DATE']) $date = $item['DC:DATE'];                   // Dublin core
    else if ($item['DCTERMS:ISSUED']) $date = $item['DCTERMS:ISSUED'];     // Dublin core
    else if ($item['DCTERMS:CREATED']) $date = $item['DCTERMS:CREATED'];   // Dublin core
    else if ($item['DCTERMS:MODIFIED']) $date = $item['DCTERMS:MODIFIED']; // Dublin core
    else if ($item['ISSUED']) $date = $item['ISSUED'];                     // Atom XML
    else if ($item['CREATED']) $date = $item['CREATED'];                   // Atom XML
    else if ($item['MODIFIED']) $date = $item['MODIFIED'];                 // Atom XML
    else $date = 'now';

    $timestamp = strtotime($date); // As of PHP 5.1.0, strtotime returns FALSE on failure instead of -1.
    if ($timestamp <= 0) {
      $timestamp = aggregator_parse_w3cdtf($date); // Returns FALSE on failure
      if (!$timestamp) {
        $timestamp = time(); // better than nothing
      }
    }

    /*
    ** Save this item.  Try to avoid duplicate entries as much as
    ** possible.  If we find a duplicate entry, we resolve it and
    ** pass along it's ID such that we can update it if needed.
    */

    if ($link && $link != $feed['link'] && $link != $feed['url']) {
      $entry = db_fetch_object(db_query("SELECT iid FROM {aggregator_item} WHERE fid = %d AND link = '%s'", $feed['fid'], $link));
    }
    else {
      $entry = db_fetch_object(db_query("SELECT iid FROM {aggregator_item} WHERE fid = %d AND title = '%s'", $feed['fid'], $title));
    }

    aggregator_save_item(array('iid' => $entry->iid, 'fid' => $feed['fid'], 'timestamp' => $timestamp, 'title' => $title, 'link' => $link, 'author' => $item['AUTHOR'], 'description' => $item['DESCRIPTION']));
  }

  /*
  ** Remove all items that are older than flush item timer:
  */

  $age = time() - variable_get('aggregator_clear', 9676800);
  $result = db_query('SELECT iid FROM {aggregator_item} WHERE fid = %d AND timestamp < %d', $feed['fid'], $age);

  if (db_num_rows($result)) {
    $items = array();
    while ($item = db_fetch_object($result)) {
      $items[] = $item->iid;
    }
    db_query('DELETE FROM {aggregator_category_item} WHERE iid IN ('. implode(', ', $items) .')');
    db_query('DELETE FROM {aggregator_item} WHERE fid = %d AND timestamp < %d', $feed['fid'], $age);
  }

  return 1;
}

function aggregator_save_item($edit) {
  if ($edit['iid'] && $edit['title']) {
    db_query('UPDATE {aggregator_item} SET title = \'%s\', link = \'%s\', author = \'%s\', description = \'%s\' WHERE iid = %d', $edit['title'], $edit['link'], $edit['author'], $edit['description'], $edit['iid']);
  }
  else if ($edit['iid']) {
    db_query('DELETE FROM {aggregator_item} WHERE iid = %d', $edit['iid']);
    db_query('DELETE FROM {aggregator_category_item} WHERE iid = %d', $edit['iid']);
  }
  else if ($edit['title'] && $edit['link']) {
    $edit['iid'] = db_next_id('{aggregator_item}_iid');
    db_query('INSERT INTO {aggregator_item} (iid, fid, title, link, author, description, timestamp) VALUES (%d, %d, \'%s\', \'%s\', \'%s\', \'%s\', %d)', $edit['iid'], $edit['fid'], $edit['title'], $edit['link'], $edit['author'], $edit['description'], $edit['timestamp']);
    // file the items in the categories indicated by the feed
    $categories = db_query('SELECT cid FROM {aggregator_category_feed} WHERE fid = %d', $edit['fid']);
    while ($category = db_fetch_object($categories)) {
      db_query('INSERT INTO {aggregator_category_item} (cid, iid) VALUES (%d, %d)', $category->cid, $edit['iid']);
    }
  }
}

function aggregator_form_category($edit = array()) {
  $form['title'] = array('#type' => 'textfield', '#title' => t('Title'), '#default_value' => $edit['title'], '#maxlength' =>  64);
  $form['description'] = array('#type' => 'textarea', '#title' => t('Description'), '#default_value' => $edit['description']);
  $form['submit'] = array('#type' => 'submit', '#value' =>t('Submit'));

  if ($edit['cid']) {
    $form['delete'] = array('#type' => 'submit', '#value' =>t('Delete'));
    $form['cid'] = array('#type' => 'hidden', '#value' => $edit['cid']);
  }

  return drupal_get_form('aggregator_form_category', $form);
}

function aggregator_save_category($edit) {
  if ($edit['cid'] && $edit['title']) {
    db_query('UPDATE {aggregator_category} SET title = \'%s\', description = \'%s\' WHERE cid = %d', $edit['title'], $edit['description'], $edit['cid']);
  }
  else if ($edit['cid']) {
    db_query('DELETE FROM {aggregator_category} WHERE cid = %d', $edit['cid']);
  }
  else if ($edit['title']) {
    // a single unique id for bundles and feeds, to use in blocks
    $next_id = db_next_id('{aggregator_category}_cid');
    db_query('INSERT INTO {aggregator_category} (cid, title, description, block) VALUES (%d, \'%s\', \'%s\', 5)', $next_id, $edit['title'], $edit['description']);
  }
}

function aggregator_form_feed($edit = array()) {
  $period = drupal_map_assoc(array(900, 1800, 3600, 7200, 10800, 21600, 32400, 43200, 64800, 86400, 172800, 259200, 604800, 1209600, 2419200), 'format_interval');

  if ($edit['refresh'] == '') {
    $edit['refresh'] = 3600;
  }


  $form['title'] = array('#type' => 'textfield', '#title' => t('Title'), '#default_value' => $edit['title'], '#maxlength' =>  64, '#description' => t('The name of the feed; typically the name of the web site you syndicate content from.'));
  $form['url'] = array('#type' => 'textfield', '#title' => t('URL'), '#default_value' => $edit['url'], '#maxlength' => 255, '#description' => t('The fully-qualified URL of the feed.'));
  $form['refresh'] = array('#type' => 'select', '#title' => t('Update interval'), '#default_value' => $edit['refresh'], '#options' => $period, '#description' => t('The refresh interval indicating how often you want to update this feed.  Requires crontab.'));

  // Handling of categories:
  $options = array();
  $values = array();
  $categories = db_query('SELECT c.cid, c.title, f.fid FROM {aggregator_category} c LEFT JOIN {aggregator_category_feed} f ON c.cid = f.cid AND f.fid = %d ORDER BY title', $edit['fid']);
  while ($category = db_fetch_object($categories)) {
    $options[$category->cid] = $category->title;
    if ($category->fid) $values[] = check_plain($category->cid);
  }
  if ($options) {
    $form['category'] = array('#type' => 'checkboxes', '#title' => t('Categorize news items'), '#default_value' => $values, '#options' => $options, '#description' => t('New items in this feed will be automatically filed in the checked categories as they are received.'));
  }
  $form['submit'] = array('#type' => 'submit', '#value' =>t('Submit'));

  if ($edit['fid']) {
    $form['delete'] = array('#type' => 'submit', '#value' =>t('Delete'));
    $form['fid'] = array('#type' => 'hidden', '#value' => $edit['fid']);
  }

  return drupal_get_form('aggregator_form_feed', $form);
}

function aggregator_save_feed($edit) {
  if ($edit['fid']) {
    // an existing feed is being modified, delete the category listings
    db_query('DELETE FROM {aggregator_category_feed} WHERE fid = %d', $edit['fid']);
  }
  if ($edit['fid'] && $edit['title']) {
    db_query('UPDATE {aggregator_feed} SET title = \'%s\', url = \'%s\', refresh = %d WHERE fid = %d', $edit['title'], $edit['url'], $edit['refresh'], $edit['fid']);
  }
  else if ($edit['fid']) {
    $result = db_query('SELECT iid FROM {aggregator_item} WHERE fid = %d', $edit['fid']);
    while ($item = db_fetch_object($result)) {
      $items[] = "iid = $item->iid";
    }
    if ($items) {
      db_query('DELETE FROM {aggregator_category_item} WHERE '. implode(' OR ', $items));
    }
    db_query('DELETE FROM {aggregator_feed} WHERE fid = %d', $edit['fid']);
    db_query('DELETE FROM {aggregator_item} WHERE fid = %d', $edit['fid']);
  }
  else if ($edit['title']) {
    // a single unique id for bundles and feeds, to use in blocks
    $edit['fid'] = db_next_id('{aggregator_feed}_fid');
    db_query('INSERT INTO {aggregator_feed} (fid, title, url, refresh, block) VALUES (%d, \'%s\', \'%s\', %d, 5)', $edit['fid'], $edit['title'], $edit['url'], $edit['refresh']);
  }
  if ($edit['title']) {
    // the feed is being saved, save the categories as well
    if ($edit['category']) {
      foreach ($edit['category'] as $cid => $value) {
        db_query('INSERT INTO {aggregator_category_feed} (fid, cid) VALUES (%d, %d)', $edit['fid'], $cid);
      }
    }
  }
}

function aggregator_get_feed($fid) {
  return db_fetch_array(db_query('SELECT * FROM {aggregator_feed} WHERE fid = %d', $fid));
}

function aggregator_get_category($cid) {
  return db_fetch_array(db_query('SELECT * FROM {aggregator_category} WHERE cid = %d', $cid));
}

function aggregator_view() {
  $result = db_query('SELECT f.*, COUNT(i.iid) AS items FROM {aggregator_feed} f LEFT JOIN {aggregator_item} i ON f.fid = i.fid GROUP BY f.fid, f.title, f.url, f.refresh, f.checked, f.link, f.description, f.etag, f.modified, f.image, f.block ORDER BY f.title');

  $output .= '<h3>'. t('Feed overview') .'</h3>';

  $header = array(t('Title'), t('Items'), t('Last update'), t('Next update'), array('data' => t('Operations'), 'colspan' => '3'));
  $rows = array();
  while ($feed = db_fetch_object($result)) {
    $rows[] = array(l($feed->title, "aggregator/sources/$feed->fid"), format_plural($feed->items, '1 item', '%count items'), ($feed->checked ? t('%time ago', array('%time' => format_interval(time() - $feed->checked))) : t('never')), ($feed->checked ? t('%time left', array('%time' => format_interval($feed->checked + $feed->refresh - time()))) : t('never')), l(t('edit'), "admin/aggregator/edit/feed/$feed->fid"), l(t('remove items'), "admin/aggregator/remove/$feed->fid"), l(t('update items'), "admin/aggregator/update/$feed->fid"));
  }
  $output .= theme('table', $header, $rows);

  $result = db_query('SELECT c.cid, c.title, count(ci.iid) as items FROM {aggregator_category} c LEFT JOIN {aggregator_category_item} ci ON c.cid = ci.cid GROUP BY c.cid, c.title ORDER BY title');

  $output .= '<h3>'. t('Category overview') .'</h3>';

  $header = array(t('Title'), t('Items'), t('Operations'));
  $rows = array();
  while ($category = db_fetch_object($result)) {
    $rows[] = array(l($category->title, "aggregator/categories/$category->cid"), format_plural($category->items, '1 item', '%count items'), l(t('edit'), "admin/aggregator/edit/category/$category->cid"));
  }
  $output .= theme('table', $header, $rows);

  return $output;
}

function aggregator_edit() {
  if ($_POST['op'] == t('Submit')) {
    if (arg(1) == 'categories') {
      aggregator_save_category($_POST['edit']);
      drupal_set_message(t('The category has been updated.'));
    }
    else {
      aggregator_save_feed($_POST['edit']);
      drupal_set_message(t('The feed has been updated.'));
    }

    menu_rebuild();
    drupal_goto($_GET['q']);
  }
  else if ($_POST['op'] == t('Delete')) {
    // Unset the title:
    unset($_POST['edit']['title']);

    if (arg(1) == 'categories') {
      aggregator_save_category($_POST['edit']);
      drupal_set_message(t('The category has been deleted.'));
    }
    else {
      aggregator_save_feed($_POST['edit']);
      drupal_set_message(t('The feed has been deleted.'));
    }

    menu_rebuild();
    drupal_goto('aggregator/'. arg(1));
  }

  if (arg(1) == 'categories') {
    $output = aggregator_form_category(aggregator_get_category(arg(2)));
  }
  else {
    $output = aggregator_form_feed(aggregator_get_feed(arg(2)));
  }

  return $output;
}


/**
 * Menu callback; displays the category edit form, or saves changes and
 * redirects to the overview page.