druproid_notifications.module

<?php
/**
 * @file
 * Druproid Notifications functionality.
 */

/**
 * Constants Definition.
 */
//
// Device Types.
//
define('DRUPROID_NOTIFICATIONS_TYPE_ID_IOS', variable_get('druproid_notifications_type_id_ios', 0));
define('DRUPROID_NOTIFICATIONS_TYPE_ID_ANDROID', variable_get('druproid_notifications_type_id_anroid', 1));

//
// Apple Variables
//
// Apple Server
define('DRUPROID_NOTIFICATIONS_APNS_HOST', variable_get('druproid_notifications_apns_host', 'gateway.push.apple.com'));
// Apple Server port.
define('DRUPROID_NOTIFICATIONS_APNS_PORT', 2195);
// Apple Feedback Server, initially set to development server.
define('DRUPROID_NOTIFICATIONS_APNS_FEEDBACK_HOST', variable_get('druproid_notifications_apns_feedback_host', 'feedback.push.apple.com'));
// Apple Feedback Server port.
define('DRUPROID_NOTIFICATIONS_APNS_FEEDBACK_PORT', 2196);
// Name of certificate, initially set to development certificate.
define('DRUPROID_NOTIFICATIONS_APNS_CERTIFICATE', variable_get('druproid_notifications_apns_certificate', 'apns-production.pem'));
// Size limit for individual payload, in bytes.
define('DRUPROID_NOTIFICATIONS_APNS_PAYLOAD_SIZE_LIMIT', 255);
// Payload sound
define('DRUPROID_NOTIFICATIONS_APNS_NOTIFICATION_SOUND', variable_get('druproid_notifications_apns_notification_sound', 'default'));
// Boolean value to indicate wether Apple's feedback service should be called
// on cron to remove unused tokens from our database.
define('DRUPROID_NOTIFICATIONS_APNS_QUERY_FEEDBACK_SERVICE', variable_get('druproid_notifications_apns_query_feedback_service', 1));
// Maximum of messages to send per stream context.
define('DRUPROID_NOTIFICATIONS_APNS_STREAM_CONTEXT_LIMIT', variable_get('druproid_notifications_apns_stream_context_limit', 1));

//
// Google Variables
//
// Google Push Notification Types
// 0 => Cloud 2 Device Messaging
// 1 => Google Cloud Messaging
define('DRUPROID_NOTIFICATIONS_GOOGLE_TYPE_C2DM', 0);
define('DRUPROID_NOTIFICATIONS_GOOGLE_TYPE_GCM', 1);
define('DRUPROID_NOTIFICATIONS_GOOGLE_TYPE', variable_get('druproid_notifications_google_type', DRUPROID_NOTIFICATIONS_GOOGLE_TYPE_GCM));

//
// C2DM Variables
//
// C2DM Credentials.
define('DRUPROID_NOTIFICATIONS_C2DM_USERNAME', variable_get('druproid_notifications_c2dm_username', ''));
define('DRUPROID_NOTIFICATIONS_C2DM_PASSWORD', variable_get('druproid_notifications_c2dm_password', ''));
define('DRUPROID_NOTIFICATIONS_C2DM_CLIENT_LOGIN_ACTION_URL', variable_get('druproid_notifications_c2dm_client_login_action_url', 'https://www.google.com/accounts/ClientLogin'));
// C2DM Server Post URL
define('DRUPROID_NOTIFICATIONS_C2DM_SERVER_POST_URL', variable_get('druproid_notifications_c2dm_server_post_url', 'https://android.apis.google.com/c2dm/send'));

//
// GCM Variables
//
// set GCM API KEY 
define('DRUPROID_NOTIFICATIONS_GCM_API_KEY_SET', variable_set('druproid_notifications_gcm_api_key', 'AIzaSyAEc4e4oiAAmTaIE8Wy9azXbNCgOGBxWrA'));
// GCM API KEY Credentials.
define('DRUPROID_NOTIFICATIONS_GCM_API_KEY', variable_get('druproid_notifications_gcm_api_key', ''));
// GCM Server Post URL
define('DRUPROID_NOTIFICATIONS_GCM_SERVER_POST_URL', variable_get('druproid_notifications_gcm_server_post_url', 'https://android.googleapis.com/gcm/send'));


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

  $items['admin/config/services/druproid_notifications'] = array(
    'type' => MENU_NORMAL_ITEM,
    'title' => 'Druproid Notifications',
    'access arguments' => array('send druproid notifications'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('druproid_notifications_admin_overview_form'),
    'description' => 'Druproid Notifications Settings.',
    'file' => 'druproid_notifications.admin.inc',
    'file path' => drupal_get_path('module', 'druproid_notifications') . '/includes',
  );

  $items['admin/config/services/druproid_notifications/overview'] = array(
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'title' => 'Overview',
    'weight' => -50,
    'access arguments' => array('send druproid notifications'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('druproid_notifications_admin_overview_form'),
    'description' => 'Druproid Notifications Settings.',
    'file' => 'druproid_notifications.admin.inc',
    'file path' => drupal_get_path('module', 'druproid_notifications') . '/includes',
  );

  $items['admin/config/services/druproid_notifications/configure'] = array(
    'type' => MENU_LOCAL_TASK,
    'title' => 'Configuration',
    'access arguments' => array('administer site configuration'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('druproid_notifications_admin_form'),
    'description' => 'Druproid Notifications Settings.',
    'file' => 'druproid_notifications.admin.inc',
    'file path' => drupal_get_path('module', 'druproid_notifications') . '/includes',
  );

  $items['admin/config/services/druproid_notifications/message'] = array(
    'type' => MENU_LOCAL_TASK,
    'title' => 'Send druproid',
    'access arguments' => array('send druproid notifications'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('druproid_notifications_mass_druproid_form'),
    'description' => 'Send a Druproid Notification',
    'file' => 'druproid_notifications.admin.inc',
    'file path' => drupal_get_path('module', 'druproid_notifications') . '/includes',
  );

  return $items;
}



/**
 * Implements of hook_cron().
 */
function druproid_notifications_cron() {
  if (DRUPROID_NOTIFICATIONS_APNS_QUERY_FEEDBACK_SERVICE) {
    druproid_notifications_apns_feedback_service();
  }
}



/**
 * Implements hook_permission().
 */
function druproid_notifications_permission() {
  return array(
    'register device token' => array(
      'title' => t('Register Device Token'),
      'description' => t('Allows users to register a device token.'),
    ),
    'remove device token' => array(
      'title' => t('Remove Device Token'),
      'description' => t('Allows users to remove a device token.'),
    ),
    'send druproid notifications' => array(
      'title' => t('Send druproid notifications'),
      'description' => t('Allow users to send a druproid notification to devices'),
    ),
  );
}



/**
 * Implements hook_services_resources().
 */
function druproid_notifications_services_resources() {
  return array(
    'druproid_notifications' => array(
      'create' => array(
        'help' => 'Registers a device token. For type, pass \'ios\' for iOS devices and \'android\' for Android devices.',
        'callback' => '_druproid_notifications_service_create_device_token',
        'file' => array(
          'type' => 'inc',
          'module' => 'druproid_notifications',
          'name' => 'includes/druproid_notifications.service'
        ),
        'access arguments' => array('register device token'),
        'access arguments append' => FALSE,
        'args' => array(
          array(
            'name' => 'token',
            'type' => 'string',
            'description' => 'Device Token',
            'optional' => FALSE,
            'source' => 'data',
          ),
          array(
            'name' => 'type',
            'type' => 'string',
            'description' => 'Device Type',
            'optional' => FALSE,
            'source' => 'data',
          ),
          array(
            'name' => 'language',
            'type' => 'string',
            'description' => 'Language',
            'optional' => TRUE,
            'source' => 'data',
          ),
        ),
      ),
      'delete' => array(
        'help' => 'Removes a registered a device token. Only needs the token.',
        'callback' => '_druproid_notifications_service_delete_device_token',
        'file' => array(
          'type' => 'inc',
          'module' => 'druproid_notifications',
          'name' => 'includes/druproid_notifications.service'
        ),
        'access arguments' => array('remove device token'),
        'access arguments append' => FALSE,
        'args' => array(
          array(
            'name' => 'token',
            'type' => 'string',
            'description' => 'Device Token',
            'optional' => FALSE,
            'source' => array('path' => '0'),
          ),
        ),
      ),
    ),
  );
}



/**
* Implements hook_privatemsg_message_insert.
*/
function druproid_notifications_privatemsg_message_insert($message) {
  if (variable_get('druproidnotifications_privatemsg_integration', 0)) {
    // Compose the payload. If the body is empty, just use the subject line.
    // Otherwise, combine subject and body.
    $payload = (empty($message->body)) ? $message->subject : $message->subject . ' ' . $message->body;
    $payload = 'From ' . $message->author->name . ': ' . $payload;

    // Compose an array of recipients.
    $recipients = array();
    foreach ($message->recipients as $recipient) {
      $recipients[] = $recipient->uid;
    }

    druproid_notifications_send_message($recipients, $payload);
  }
}



/**
 * Determine if this user has already stored a token
 * in the database. The same device token can be
 * registered for multiple users, because multiple
 * users can login from the same device.
 *
 * @param $token
 *   Device Token.
 * @param $uid
 *   User ID.
 * @param $exclude
 *   Set this to true to find (at least one) other user(s) who have this
 *   token stored. Optional, defaults to false.
 *
 * @return
 *   User ID of token, if found.
 */
function druproid_notifications_find_token($token = '', $uid = '', $exclude = FALSE) {
  if ($token == '') {
    return FALSE;
  }

  $query = db_select('druproid_notifications_tokens', 'dnt');
  $query->fields('dnt', array('token'));
  $query->condition('dnt.token', $token);
  if ($exclude) {
    $query->condition('dnt.uid', $uid, '!=');
    $query->range(0, 1);
  }
  else {
    $query->condition('dnt.uid', $uid);
  }

  $result = $query->execute();
  return $result->fetchField();
}



/**
 * Store a token in the database.
 * Removes all spaces in the token.
 *
 * @param $token
 *   Device token.
 * @param $type_id
 *   Device type id.
 * @param $uid
 *   User ID.
 * @param $language
 *   Language that this token is registered for, optional.
 *
 * @return
 *   Failure to write a record will return FALSE, Otherwise SAVED_NEW.
 */
function druproid_notifications_store_token($token = '', $type_id = '', $uid = '', $language = '') {
   // Let modules modify the token before it is saved to the database.
  foreach(module_implements('druproid_notifications_store_token') as $module) {
    $function = $module . '_druproid_notifications_store_token';
    $function($token, $type_id, $uid);
  }

  if (!is_string($token) || !is_numeric($type_id) || !is_numeric($uid)) {
    return FALSE;
  }

  // Default language to site default.
  if ($language == '') {
    $default_language = language_default();
    $language = $default_language->language;
  }

  // Write record.
  $table = 'druproid_notifications_tokens';
  $record = new stdClass();
  $record->token = $token;
  $record->uid = $uid;
  $record->type = $type_id;
  $record->language = $language;
  $record->timestamp = time();
  return drupal_write_record($table, $record);
}



/**
 * Open an APNS connection.
 * Should be closed by calling fclose($connection) after usage.
 */
function druproid_notifications_open_apns() {
  // Determine the absolute path of the certificate.
  // @see http://stackoverflow.com/questions/809682
  $apns_cert = _druproid_notifications_get_apns_certificate();

  // Create a stream context.
  $stream_context = stream_context_create();
  // Set options on the stream context.
  stream_context_set_option($stream_context, 'ssl', 'local_cert', $apns_cert);

  //If the user has a passphrase stored, we use it.
  $passphrase = variable_get('druproid_notifications_apns_passphrase', '');
  if(strlen($passphrase)) {
    stream_context_set_option($stream_context, 'ssl', 'passphrase', $passphrase);
  }


  // Open an Internet socket connection.
  $apns = stream_socket_client('ssl://' . DRUPROID_NOTIFICATIONS_APNS_HOST . ':' . DRUPROID_NOTIFICATIONS_APNS_PORT, $error, $error_string, 2, STREAM_CLIENT_CONNECT, $stream_context);
  if (!$apns) {
    watchdog('druproid_notifications', 'Connection to Apple Notification Server failed.', NULL, WATCHDOG_ERROR);
    return FALSE;
  }
  else {
    return $apns;
  }
}



/**
 * Check size of a druproid notification payload.
 * Payload can't exceed DRUPROID_NOTIFICATIONS_APNS_PAYLOAD_SIZE_LIMIT.
 *
 * @param $payload
 *   Message.
 *
 * @return
 *   Returns true if message is below the limit, false otherwise.
 */
function druproid_notifications_check_payload_size($payload = '') {
  if ($payload == '') {
    return FALSE;
  }

  // JSON-encode the payload.
  $payload = json_encode($payload);

  // Verify that the payload doesn't exceed limit.
  $payload_size = mb_strlen($payload, '8bit');
  $size_valid = ($payload_size > DRUPROID_NOTIFICATIONS_APNS_PAYLOAD_SIZE_LIMIT) ? FALSE : TRUE;
  return $size_valid;
}



/**
* Send out druproid notifications, switch automatically between delivery method.
*
* @param $recipients
*   Array of user ids.
* @param $message
*   Payload to send.
*/
function druproid_notifications_send_message($recipients, $message) {
  if (!is_array($recipients) || !is_string($message)) {
    return FALSE;
  }

  // Let modules modify the message before it is sent.
  foreach(module_implements('druproid_notifications_send_message') as $module) {
    $function = $module . '_druproid_notifications_send_message';
    $function($message);
  }

  // Shorten the message to 255 characters / 8 bit.
  $message = truncate_utf8($message, DRUPROID_NOTIFICATIONS_APNS_PAYLOAD_SIZE_LIMIT, TRUE, TRUE);

  // Convert the payload into the correct format for delivery.
  $payload = array('alert' => $message);

  // Determine if any of the recipients have one or multiple tokens stored.
  $tokens = array();
  foreach ($recipients as $uid) {
    $user_tokens = druproid_notification_get_user_tokens($uid);
    if (!empty($user_tokens)) {
      $tokens = array_merge($tokens, $user_tokens);
    }
  }

  // Stop right here if none of these users have any tokens.
  if (empty($tokens)) {
    return FALSE;
  }

  // Group tokens into types.
  $tokens_ios = array();
  $tokens_android = array();
  foreach ($tokens as $token) {
    switch ($token['type']) {
      case DRUPROID_NOTIFICATIONS_TYPE_ID_IOS:
      $tokens_ios[] = $token['token'];
      break;

      case DRUPROID_NOTIFICATIONS_TYPE_ID_ANDROID:
      $tokens_android[] = $token['token'];
      break;
    }
  }

  // Send payload to iOS recipients.
  if (!empty($tokens_ios)) {
    // Convert the payload into the correct format for APNS.
    $payload_apns = array('aps' => $payload);
    $result = druproid_notifications_apns_send_message($tokens_ios, $payload_apns);
  }
  // Send payload to Android recipients if configured correctly.
  if (!empty($tokens_android) && ((DRUPROID_NOTIFICATIONS_C2DM_USERNAME && DRUPROID_NOTIFICATIONS_C2DM_PASSWORD) || DRUPROID_NOTIFICATIONS_GCM_API_KEY)) {
    // Determine which method to use for Google push notifications.
    switch (DRUPROID_NOTIFICATIONS_GOOGLE_TYPE) {
      case DRUPROID_NOTIFICATIONS_GOOGLE_TYPE_C2DM:
      $result = druproid_notifications_c2dm_send_message($tokens_android, $payload);
      break;

      case DRUPROID_NOTIFICATIONS_GOOGLE_TYPE_GCM:
      $result = druproid_notifications_gcm_send_message($tokens_android, $payload);
      break;
    }
  }
}



/**
 * Send out druproid notifications through APNS.
 *
 * @param $tokens
 *   Array of iOS tokens
 * @param $payload
 *   Payload to send. Minimum requirement
 *   is a nested array in this format:
 *   $payload = array(
 *     'aps' => array(
 *       'alert' => 'Druproid Notification Test',
 *     );
 *   );
 *
 * @return
 *   Array with the following keys:
 *   - count_attempted (# of attempted messages sent)
 *   - count_success   (# of successful sends)
 *   - success         (# boolean)
 *   - message         (Prepared result message)
 */
function druproid_notifications_apns_send_message($tokens, $payload) {
  if (!is_array($tokens) || empty($payload) || (is_array($tokens) && empty($tokens))) {
    return FALSE;
  }

  $payload_apns = array();

  // Allow for inclusion of custom payloads.
  foreach ($payload as $key => $value) {
    if ($key != 'aps') {
      $payload_apns[$key] = $value;
    }
  }

  // Add the default 'aps' key for the payload.
  $payload_apns['aps'] = $payload['aps'];

  // Set the default sound if no sound was set.
  if (!isset($payload_apns['aps']['sound'])) {
    $payload_apns['aps']['sound'] = DRUPROID_NOTIFICATIONS_APNS_NOTIFICATION_SOUND;
  }
  
  // JSON-encode the payload.
  $payload_apns = json_encode($payload_apns);

  $result = array(
    'count_attempted' => 0,
    'count_success' => 0,
    'success' => 0,
    'message' => '',
  );

  // Send a druproid notification to every recipient.
  $stream_counter = 0;
  foreach ($tokens as $token) {
    // Open an apns connection, if necessary.
    if ($stream_counter == 0) {
      $apns = druproid_notifications_open_apns();
      if (!$apns) {
        $result['message'] = t('APNS connection could not be established. Check to make sure you are using a valid certificate file.');
        return $result;
      }
    }
    $stream_counter++;

    $result['count_attempted']++;
    $apns_message = chr(0) . chr(0) . chr(32) . pack('H*', $token) . chr(0) . chr(strlen($payload_apns)) . $payload_apns;
    // Write the payload to the currently active streaming connection.
    $success = fwrite($apns, $apns_message);
    if ($success) {
      $result['count_success']++;
    }
    elseif ($success == 0 || $success == FALSE || $success < strlen($apns_message)) {
      $error_message = array(
        'message' => t('APNS message could not be sent.'),
        'token' => 'Token: ' . $token,
        'data' => 'fwrite returned: ' . $success,
      );
      watchdog('druproid_notifications', implode($error_message, '<br />'));
    }

    // Reset the stream counter if no more messages should
    // be sent with the current stream context.
    // This results in the generation of a new stream context
    // at the beginning of this loop.
    if ($stream_counter >= DRUPROID_NOTIFICATIONS_APNS_STREAM_CONTEXT_LIMIT) {
      $stream_counter = 0;
    }
  }

  // Close the apns connection.
  fclose($apns);

  $result['message'] = t('Successfully sent !count_success iOS push messages (attempted to send !count messages).', array('!count_success' => $result['count_success'], '!count' => $result['count_attempted']));
  $result['success'] = TRUE;
  return $result;
}


/**
 * Determine the auth string from C2DM server.
 */
function druproid_notifications_c2dm_token() {
  $data = array(
    'Email'         => DRUPROID_NOTIFICATIONS_C2DM_USERNAME,
    'Passwd'        => DRUPROID_NOTIFICATIONS_C2DM_PASSWORD,
    'accountType'   => 'HOSTED_OR_GOOGLE',
    'source'        => 'Company-AppName-Version',
    'service'       => 'ac2dm',
  );

  $curl = curl_init();
  curl_setopt($curl, CURLOPT_URL, DRUPROID_NOTIFICATIONS_C2DM_CLIENT_LOGIN_ACTION_URL);
  curl_setopt($curl, CURLOPT_FOLLOWLOCATION, TRUE);
  curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, 0);
  curl_setopt($curl, CURLOPT_POST, TRUE);
  curl_setopt($curl, CURLOPT_RETURNTRANSFER, TRUE);
  curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
  $response = curl_exec($curl);
  curl_close($curl);

  // Get the auth token.
  preg_match("/Auth=([a-z0-9_\-]+)/i", $response, $matches);
  $auth_token = $matches[1];

  if (!$auth_token) {
    watchdog('druproid_notifications', 'Google C2DM Server did not provide an authentication token.', NULL, WATCHDOG_ERROR);
  }
  else {
    return $auth_token;
  }
}




/**
 * Send out druproid notifications through C2DM.
 *
 * @param $tokens
 *   Array of iOS tokens
 * @param $payload
 *   Payload to send.
 *
 * @return
 *   Array with the following keys:
 *   - count_attempted (# of attempted messages sent)
 *   - count_success   (# of successful sends)
 *   - success         (# boolean)
 *   - message         (Prepared result message)
 */
function druproid_notifications_c2dm_send_message($tokens, $payload) {
  if (!is_array($tokens) || empty($payload) || (is_array($tokens) && empty($tokens))) {
    return FALSE;
  }

  // Determine an updated authentication token.
  // Google is very vague about how often this token changes,
  // so we'll just get a new token every time.
  $auth_token = druproid_notifications_c2dm_token();
  if (!$auth_token) {
    $result['message'] = t('Google C2DM Server did not provide an authentication token. Check your C2DM credentials.');
    return $result;
  }

  // Define an array of result values.
  $result = array(
    'count_attempted' => 0,
    'count_success' => 0,
    'success' => 0,
    'message' => '',
  );

  // Define the header.
  $headers = array();
  $headers[] = 'Authorization: GoogleLogin auth=' . $auth_token;

  // Send a druproid notification to every recipient.
  foreach ($tokens as $token) {
    $result['count_attempted']++;

    // Convert the payload into the correct format for C2DM payloads.
    // Prefill an array with values from other modules first.
    $data = array();
    foreach ($payload as $key => $value) {
      if ($key != 'alert') {
        $data['data.' . $key] = $value;
      }
    }
    // Fill the default values required for each payload.
    $data['registration_id'] = $token;
    $data['collapse_key'] = time();
    $data['data.message'] = $payload['alert'];

    $curl = curl_init();
    curl_setopt($curl, CURLOPT_URL, druproid_NOTIFICATIONS_C2DM_SERVER_POST_URL);
    curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE);
    curl_setopt($curl, CURLOPT_POST, TRUE);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, TRUE);
    curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
    $response = curl_exec($curl);
    $info = curl_getinfo($curl);
    curl_close($curl);

    // If Google's server returns a reply, but that reply includes an error, log the error message.
    if ($info['http_code'] == 200 && (isset($response) && preg_match('/Error/', $response))) {
      watchdog('druproid_notifications', "Google's Server returned an error: " . $response, NULL, WATCHDOG_ERROR);

      // If the device token is invalid or not registered (anymore because the user
      // has uninstalled the application), remove this device token.
      if (preg_match('/InvalidRegistration/', $response) || preg_match('/NotRegistered/', $response)) {
        druproid_notifications_purge_token($token);
        watchdog('daddyhunt_apns', 'C2DM token not valid anymore. Removing token ' . $token);
      }
    }

    // Success if the http response status is 200 and the response
    // data does not containt the word "Error".
    if ($info['http_code'] == 200 && (isset($response) && !preg_match('/Error/', $response))) {
      $result['count_success']++;
    }
  }

  $result['message'] = t('Successfully sent !count_success Android push messages (attempted to send !count messages).', array('!count_success' => $result['count_success'], '!count' => $result['count_attempted']));
  $result['success'] = TRUE;
  return $result;
}

/**
 * Send out druproid notifications through GCM.
 *
 * @link http://developer.android.com/guide/google/gcm/index.html
 *
 * @param $tokens
 *   Array of gcm tokens
 * @param $payload
 *   Payload to send.
 *
 * @return
 *   Array with the following keys:
 *   - count_attempted (# of attempted messages sent)
 *   - count_success   (# of successful sends)
 *   - success         (# boolean)
 *   - message         (Prepared result message)
 */
function druproid_notifications_gcm_send_message($tokens, $payload) {
  if (!is_array($tokens) || empty($payload) || (is_array($tokens) && empty($tokens))) {
    return FALSE;
  }

  // Define an array of result values.
  $result = array(
    'count_attempted' => 0,
    'count_success' => 0,
    'success' => 0,
    'message' => '',
  );

  // Define the header.
  $headers = array();
  $headers[] = 'Content-Type:application/json';
  $headers[] = 'Authorization:key=' . DRUPROID_NOTIFICATIONS_GCM_API_KEY;


  // Check of many token bundles can be build.
  $token_bundles = ceil(count($tokens) / 1000);
  $result['count_attempted'] = count($tokens);

  // Send a druproid notification to every recipient.
  for ($i = 0; $i < $token_bundles; $i++) {
    // Create a token bundle.
    $bundle_tokens = array_slice($tokens, $i * 1000, 1000, FALSE);

    // Convert the payload into the correct format for C2DM payloads.
    // Prefill an array with values from other modules first.
    $data = array();
    foreach ($payload as $key => $value) {
      if ($key != 'alert') {
        $data['data'][$key] = $value;
      }
    }
    // Fill the default values required for each payload.
    $data['registration_ids'] = $bundle_tokens;
    $data['collapse_key'] = (string) time();
    $data['data']['message'] = $payload['alert'];

    $curl = curl_init();
    curl_setopt($curl, CURLOPT_URL, DRUPROID_NOTIFICATIONS_GCM_SERVER_POST_URL);
    curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE);
    curl_setopt($curl, CURLOPT_POST, TRUE);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, TRUE);
    curl_setopt($curl, CURLOPT_POSTFIELDS, json_encode($data));
    $response_raw = curl_exec($curl);
    $info = curl_getinfo($curl);
    curl_close($curl);

    $response = FALSE;
    if (isset($response_raw)) {
      $response = json_decode($response_raw);
    }

    // If Google's server returns a reply, but that reply includes an error,
    // log the error message.
    if ($info['http_code'] == 200 && (!empty($response->failure))) {
      watchdog('druproid_notifications', "Google's Server returned an error: " . $response_raw, NULL, WATCHDOG_ERROR);

      // Analyze the failure.
      foreach ($response->results as $token_index => $message_result) {
        if (!empty($message_result->error)) {
          // If the device token is invalid or not registered (anymore because the user
          // has uninstalled the application), remove this device token.
          if ($message_result->error == 'NotRegistered' || $message_result->error == 'InvalidRegistration') {
            druproid_notifications_purge_token($bundle_tokens[$token_index]);
            watchdog('druproid_notifications', 'GCM token not valid anymore. Removing token ' . $bundle_tokens[$token_index]);
          }
        }
      }
    }

    // Count the successful sent druproid notifications if there are any.
    if ($info['http_code'] == 200 && !empty($response->success)) {
      $result['count_success'] += $response->success;
    }
  }

  $result['message'] = t('Successfully sent !count_success Android push messages (attempted to send !count messages).', array('!count_success' => $result['count_success'], '!count' => $result['count_attempted']));
  $result['success'] = TRUE;
  return $result;
}


/**
  * Determine all recipients from a specific device type.
  *
  * @param $type_id
  *   Device Type ID.
  * @param $language
  *   Language code, optional.
  * @param $raw
  *   Boolean, set true to retrieve the raw query results.
  *
  * @return
  *   Array of results, null if no entries.
  */
function druproid_notifications_get_tokens($type_id = '', $language = FALSE, $raw = FALSE) {
  // Make sure this type_id is supported.
  $valid_type_ids = array(DRUPROID_NOTIFICATIONS_TYPE_ID_IOS, DRUPROID_NOTIFICATIONS_TYPE_ID_ANDROID);
  if (!in_array($type_id, $valid_type_ids)) {
    return FALSE;
  }

  // Select all tokens for this type id.
  $query = db_select('druproid_notifications_tokens', 'dnt');
  $query->fields('dnt', array('token'));
  $query->condition('dnt.type', $type_id);
  // If language code is passed, limit the results by language.
  if ($language) {
    $query->condition('dnt.language', $language);
  }
  $result = $query->execute();

  // Return raw result, if needed.
  if ($raw) {
    return $result;
  }
  // Otherwise, create an array of tokens.
  else {
    $tokens = array();
    foreach ($result as $record) {
      $tokens[] = $record->token;
    }
    return $tokens;
  }
}



/**
* Determine all tokens for a specfic user.
*
* @param @uid
*   User ID.
*
* @return
*   Nested array of tokens, with user id, druproid notification type
*   and token.
*/
function druproid_notification_get_user_tokens($uid = '') {
  if ($uid == '' || !is_numeric($uid)) {
    return FALSE;
  }

  // Select all tokens for this user.
  $query = db_select('druproid_notifications_tokens', 'dnt');
  $query->fields('dnt', array('token', 'uid', 'type'));
  $query->condition('dnt.uid', $uid);
  $result = $query->execute();

  $tokens = array();
  foreach ($result as $record) {
    $tokens[$record->token] = array(
      'token' => $record->token,
      'uid' => $record->uid,
      'type' => $record->type,
    );
  }

  return $tokens;
}



/**
 * Determine any languages used in the push
 * notifications table.
 */
function druproid_notifications_used_languages() {
  $query = db_select('druproid_notifications_tokens', 'dnt');
  $query->fields('dnt', array('language'));
  $query->distinct();
  $result = $query->execute();

  // Convert the records into an array with
  // full language code available.
  include_once DRUPAL_ROOT . '/includes/iso.inc';
  $languages = _locale_get_predefined_list();

  $used_languages = array();
  foreach ($result as $record) {
    $used_languages[$record->language] = $languages[$record->language][0];
  }

  if (!empty($used_languages)) {
    // Sort the languages alphabetically.
    $used_langauges = asort($used_languages);
    // Add an "All" option.
    array_unshift($used_languages, 'All Recipients');
  }

  return $used_languages;
}



/**
 * Delete a token.
 *
 * @param $token
 */
function druproid_notifications_purge_token($token = '') {
  if ($token == '' || !is_string($token)) {
    return FALSE;
  }

  $query = db_delete('druproid_notifications_tokens');
  $query->condition('token', $token);
  return $query->execute();
}



/**
 * Connect to Apple's feedback server to remove unused device tokens.
 * Connection modeled after daddyhunt_apns_send_notifications function.
 *
 * @see http://stackoverflow.com/questions/4774681/php-script-for-apple-push-notification-feedback-service-gets-timeout-every-time
 * @see http://stackoverflow.com/questions/1278834/php-technique-to-query-the-apns-feedback-server/2298882#2298882
 */
function druproid_notifications_apns_feedback_service() {
  // Create a Stream context and open an Internet socket connection.
  $stream_context = stream_context_create();
  $apns_cert = _druproid_notifications_get_apns_certificate();
  stream_context_set_option($stream_context, 'ssl', 'local_cert', $apns_cert);
  $apns = stream_socket_client('ssl://' . DRUPROID_NOTIFICATIONS_APNS_FEEDBACK_HOST . ':' . DRUPROID_NOTIFICATIONS_APNS_FEEDBACK_PORT, $error, $error_string, 2, STREAM_CLIENT_CONNECT, $stream_context);
  if (!$apns) {
    return;
  }

  // Gather expired tokens in an array
  $tokens = array();
    while (!feof($apns)) {
    $data = fread($apns, 38);
    if (strlen($data)) {
      $tokens[] = unpack("N1timestamp/n1length/H*devtoken", $data);
    }
  }

  // Close connection.
  fclose($apns);

  if (empty($tokens)) {
    watchdog('druproid_notifications', 'Apple\'s feedback service returned no tokens to be removed.');
    return;
  }

  // Remove all tokens that are not valid anymore.
  $counter = 0;
  foreach ($tokens as $token) {
    druproid_notifications_purge_token($token['devtoken']);
    $counter++;
  }

  // Give some feedback after the process finished.
  watchdog('druproid_notifications', '!count were removed after pulling the Apple feedback service.', array('!count' => $counter));

}

/**
 * Get the full path to the APNS certificate.
 *
 * @return string
 *   The path to the certificate file on the server.
 */
function _druproid_notifications_get_apns_certificate() {
  $path = variable_get('druproid_notifications_apns_certificate_folder', '');

  if (empty($path)) {
    $path = dirname(__FILE__) . DIRECTORY_SEPARATOR . 'certificates' . DIRECTORY_SEPARATOR;
  }

  $path .= DRUPROID_NOTIFICATIONS_APNS_CERTIFICATE;

  if (!file_exists($path)) {
    watchdog('druproid_notifications', 'Cannot find apns certificate file at @path', array('@path' => $path), WATCHDOG_WARNING, l(t('settings'), 'admin/config/services/druproid_notifications/configure'));
  }

  return $path;
}

/**
 *  Send Notification to register android device for new user created
 */
 function druproid_notifications_user_insert(&$edit, $account, $category)
  {
     $tokens_android = druproid_notifications_get_tokens(DRUPROID_NOTIFICATIONS_TYPE_ID_ANDROID, false);
     global $base_url;
     $payload['alert']['site_url'] = $base_url;
     $payload['alert']['action'] = "user";

     $user['uid'] = $account->uid;
     $user['name'] = $account->name;
     $user['mail'] = $account->mail;
     $user['status'] = $account->status;
    
     $payload['alert']['data'] = $user;
     druproid_notifications_gcm_send_message($tokens_android, $payload);
  }  

/**
 *  Send Notification to register android device for new node created
 */
  function druproid_notifications_node_insert($node) 
  {
     
     $tokens_android = druproid_notifications_get_tokens(DRUPROID_NOTIFICATIONS_TYPE_ID_ANDROID, false);
     global $base_url;
     $payload['alert']['site_url'] = $base_url;
     $payload['alert']['action'] = "node";

     $node_data['nid'] = $node->nid;
     $node_data['title'] = $node->title;
     $node_data['type'] = $node->type;
     $node_data['uid'] = $node->uid;
     $node_data['name'] = $node->name;

     $payload['alert']['data'] = $node_data;
     druproid_notifications_gcm_send_message($tokens_android, $payload);
  }
/**
 *  Send Notification to register android device for new comment created
 */
  function druproid_notifications_comment_insert($comment) 
  {
    $tokens_android = druproid_notifications_get_tokens(DRUPROID_NOTIFICATIONS_TYPE_ID_ANDROID, false);
    global $base_url;
    $payload['alert']['site_url'] = $base_url;
    $payload['alert']['action'] = "comment";

    $comment_data['cid'] = $comment->cid; 
    $comment_data['subject'] = $comment->subject;
    $comment_data['status'] = $comment->status;
    $comment_data['nid'] = $comment->nid;
    $comment_data['uid'] = $comment->uid;
    $comment_data['name'] = $comment->name;

    $payload['alert']['data'] = $comment_data;
    druproid_notifications_gcm_send_message($tokens_android, $payload);
  }