farmOS/farm_sensor.module

<?php
/**
 * @file
 * Code for the Farm Sensor feature.
 */

include_once 'farm_sensor.features.inc';

/**
 * Implements hook_entity_load().
 */
function farm_sensor_entity_load($entities, $type) {

  // Only act on farm_asset entities.
  if ($type != 'farm_asset') {
    return;
  }

  // Iterate through the loaded assets...
  foreach ($entities as $entity) {

    // Only act on sensors...
    if ($entity->type != 'sensor') {
      continue;
    }

    // Load the sensor information from the {farm_sensor} database.
    $query = db_select('farm_sensor', 's');
    $query->fields('s');
    $query->condition('id', $entity->id);
    $result = $query->execute();
    $sensor_info = $result->fetchAssoc();

    // Only continue if sensor info was returned.
    if (empty($sensor_info)) {
      continue;
    }

    // Assign the entity's sensor type.
    $entity->sensor_type = $sensor_info['type'];

    // Assign the entity's sensor settings.
    $entity->sensor_settings = unserialize($sensor_info['settings']);
  }
}

/**
 * Implements hook_entity_insert().
 */
function farm_sensor_entity_insert($entity, $type) {
  _farm_sensor_entity_save($entity, $type);
}

/**
 * Implements hook_entity_update().
 */
function farm_sensor_entity_update($entity, $type) {
  _farm_sensor_entity_save($entity, $type);
}

/**
 * Helper function for saving farm sensor information on entity insert and update.
 *
 * @param $entity
 *   The entity being saved.
 * @param $type
 *   The type of entity being saved.
 */
function _farm_sensor_entity_save($entity, $type) {

  // Only act on farm asset entities.
  if ($type != 'farm_asset') {
    return;
  }

  // Only act on sensor assets.
  if ($entity->type != 'sensor') {
    return;
  }

  // Only act if a sensor type is set.
  if (empty($entity->sensor_type)) {
    return;
  }

  // Save the sensor record.
  farm_sensor_save($entity->id, $entity->sensor_type, $entity->sensor_settings);
}

/**
 * Implements hook_entity_delete().
 */
function farm_sensor_entity_delete($entity, $type) {

  // Only act on farm asset entities.
  if ($type != 'farm_asset') {
    return;
  }

  // Only act on sensor assets.
  if ($entity->type != 'sensor') {
    return;
  }

  // Delete sensor record.
  farm_sensor_delete($entity->id);
}

/**
 * Implements hook_farm_sensor_type_info().
 */
function farm_sensor_farm_sensor_type_info() {
  return array(
    'none' => array(
      'label' => t('None'),
      'description' => t('No sensor type.'),
    ),
  );
}

/**
 * Get farm sensor types.
 *
 * @return array
 *   Returns an array of sensors type information provided by other modules.
 */
function farm_sensor_types() {

  // Gather type information from other modules.
  $sensor_types = module_invoke_all('farm_sensor_type_info');

  // Return it.
  return $sensor_types;
}

/**
 * Helper function for saving farm sensor information.
 *
 * @param int $id
 *   The farm sensor asset id.
 * @param string $type
 *   The sensor type.
 * @param array $settings
 *   An array of sensor settings.
 */
function farm_sensor_save($id, $type, $settings = array()) {

  // Delete any existing
  farm_sensor_delete($id);

  // Insert a new record.
  $record = array(
    'id' => $id,
    'type' => $type,
    'settings' => $settings,
  );
  drupal_write_record('farm_sensor', $record);
}

/**
 * Helper function for deleting farm sensor information.
 *
 * @param int $id
 *   The farm sensor asset id.
 */
function farm_sensor_delete($id) {
  db_delete('farm_sensor')->condition('id', $id)->execute();
}