pixel_pusher.module

<?php

/**
 * Pixel Pusher
 *
 * Integrates with Pixel Ping, a pixel-tracking service from Pro Publica
 * and DocumentCloud that runs on Node.js.
 *
 * http://documentcloud.github.com/pixel-ping/
 * http://www.propublica.org/nerds/item/pixel-ping-a-nodejs-stats-tracker
 *
 * Requires json_decode(), and thus either PHP 5.2 or the json PECL
 * extension.
 */

/**
 * Implementation of hook_menu().
 */
function pixel_pusher_menu() {
  $items = array();

  $items['pixel_pusher/save_hits'] = array(
    'title' => t('Pixel Ping flush callback'),
    'page callback' => 'pixel_pusher_save_hits',
    'type' => MENU_CALLBACK,
    'access arguments' => array('access content'),
  );

  $items['admin/settings/pixel_pusher'] = array(
    'title' => t('Pixel Pusher settings'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('pixel_pusher_admin_settings'),
    'type' => MENU_NORMAL_ITEM,
    'access arguments' => array('administer pixel_pusher'),
  );

  return $items;
}

/**
 * Implementation of hook_perm().
 */
function pixel_pusher_perm() {
  return array('administer pixel_pusher');
}

/**
 * Admin settings form.
 */
function pixel_pusher_admin_settings() {
  $form['pixel_ping'] = array(
    '#type' => 'fieldset',
    '#title' => t('Pixel Ping integration'),
    '#collapsible' => TRUE,
  );

  $form['pixel_ping']['pixel_pusher_remote'] = array(
    '#type' => 'textfield',
    '#title' => t('Pixel Ping server'),
    '#default_value' => variable_get('pixel_pusher_remote', 'http://127.0.0.1'),
    '#description' => 'The base URL where the pixel will be served.  Do not include <em>/pixel.gif</em> or a trailing slash; for instance, enter <em>http://something.com:9000</em>.',
  );

  $form['pixel_pusher_debug'] = array(
    '#type' => 'checkbox',
    '#title' => t('Enable verbose logging'),
    '#default_value' => variable_get('pixel_pusher_debug', 0),
    '#description' => t('<strong>Not recommended for production environments:</strong> Activate this option if you want many debug messages sent to Watchdog.'),
  );

  return system_settings_form($form);
}

/**
 * Implementation of hook_block().
 */
function pixel_pusher_block($op = 'list', $delta = 0, $edit = array()) {
  switch ($op) {
    case 'list':
      $blocks[0] = array(
        'info' => t('Pixel Counter tracker pixel'),
        'weight' => 0,
        'cache' => BLOCK_CACHE_PER_PAGE,
      );

      return $blocks;

    case 'view':
      $block = array();

      switch ($delta) {
        case 0:
          if (!empty($_GET['q'])) {
            $nid = str_replace('node/', '', $_GET['q']);
            $node = new stdClass();
            $node->nid = $nid;
          }
          else {
            $node = menu_get_object('node');
          }

          if (!empty($node) && is_null(arg(2))) {
            $block['subject'] = FALSE;
            $server_url = variable_get('pixel_pusher_remote', 'http://127.0.0.1');
            $block['content'] = '<img src="' . $server_url . '/pixel.gif?key=node,' . $node->nid . '" width="1" height="1" alt="" />';
          }
          return $block;
      }
  }
}

/**
 * Callback for Pixel Ping's flush request.  A 'json'
 * object should be posted with keys and hit counts.
 */
function pixel_pusher_save_hits() {
  if (!empty($_REQUEST['json'])) {
    $results = json_decode($_REQUEST['json'], TRUE);
    if ($results) {
      pixel_pusher_write_hits($results);
      if (variable_get('pixel_pusher_debug', 0)) {
        watchdog('Pixel Ping', '@var' , array('@var' => print_r($results, TRUE)), WATCHDOG_DEBUG);
      }
    }
  }
  else {
    watchdog('Pixel Ping', 'No "json" object received.  Raw data: @var', array('@var' => print_r($_REQUEST, TRUE)), WATCHDOG_WARNING);
  }
}

/**
 * Given a parsed $results array from pixel_pusher_save_hits, increment
 * the appropriate nodes.
 *
 * Almost all of this code is copied, with gratitude, from the excellent
 * boost_stats.php script that ships with the Boost module.
 */
function pixel_pusher_write_hits($results) {

  if (!empty($results)) {
    foreach ($results as $key => $val) {

      $path = split(',', $key);

      if ('node' == $path[0] && !empty($path[1])) {

        // Mimic the "node view" event.
        db_query('UPDATE {node_counter} SET daycount = daycount + %d, totalcount = totalcount + %d, timestamp = %d WHERE nid = %d',
          $val, $val, time(), $path[1]);

        // If we affected 0 rows, this is the first time viewing the node.
        if (!db_affected_rows()) {

          // We must create a new row to store counters for the new node.
          db_query('INSERT INTO {node_counter} (nid, daycount, totalcount, `timestamp`) VALUES (%d, %d, %d, %d)',
            $path[1], $val, $val, time());
        }

        if (variable_get('pixel_pusher_debug', 0)) {
          watchdog('Pixel Pusher', 'Updated node nid=@node by @amount', array('@node' => $path[1], '@amount' => $val));
        }
      }

    }
  }
}