<?php

/**
 * @file
 * Minimal crawler to regenerate the cache as pages are expired.
 */

/**
 * Implements hook_menu().
 */
function boost_crawler_menu() {
  $items = array();

  $items['admin/config/system/boost/crawler'] = array(
    'title' => 'Crawler',
    'description' => 'Configuration for the Boost crawler.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('boost_crawler_admin_settings'),
    'access arguments' => array('administer site configuration'),
    'type' => MENU_LOCAL_TASK,
    'file' => 'boost_crawler.admin.inc',
  );

  return $items;
}

/**
 * Implements hook_cron_queue_info()
 */
function boost_crawler_cron_queue_info() {
  $queues['boost_crawler'] = array(
    'worker callback' => 'boost_crawler_run',
    'time' => variable_get('boost_crawl_queue_seconds', 30), // max run time to claim per cron run (in seconds).
  );

  return $queues;
}

/**
 * Implements hook_expire_cache (from the 'expire' module)
 */
function boost_crawler_expire_cache($urls) {
  global $base_root;

  if (variable_get('boost_crawl_on_cron', FALSE)) {
    foreach ($urls as $url) {
      // Put URLs in a queue for processing by cron
      // http://drupal.org/node/1074080#comment-4590150
      $queue = DrupalQueue::get('boost_crawler');
 
      // Check if the URL to be flushed matches our base URL
      if (strpos($base_root, $url) == 0) {
        $queue->createItem($url);
      }
    }
  }
}

/**
 * Worker Callback for the boost_crawler cron queue.
 */
function boost_crawler_run($url) {
  // Not doing async requests in order not to kill the server
  // and also for the 'time' limit of the queue to make sense.
  $options = array(
    'headers' => array(
      'Pragma' => 'no-cache',
    ),
  );

  httprl_request($url, $options);
  $request = httprl_send_request();

  boost_log('Crawler fetched !url', array('!url' => $url), WATCHDOG_DEBUG);
}