class Tx_MyExt_ViewHelpers_UidViewHelper extends Tx_Fluid_Core_ViewHelper_AbstractViewHelper {

  /**
   * @var Tx_Extbase_Configuration_ConfigurationManagerInterface
   */
  protected $configurationManager;
  
  /**
   * @param Tx_Extbase_Configuration_ConfigurationManagerInterface An instance of the Configuration Manager
   * @return void
   */
  public function injectConfigurationManager(Tx_Extbase_Configuration_ConfigurationManagerInterface $configurationManager) {
    $this->configurationManager = $configurationManager;
  }

  /**
   * Set uid of the content element
   *
   * @return int $uid The uid of the content element
   */
  public function render() {
    // fallback
    $uid = uniqid();
    
    if ($this->templateVariableContainer->exists("contentObjectData")) {
      // this works for templates but not for partials
      $contentObjectData = $this->templateVariableContainer->get("contentObjectData");
      $uid = $contentObjectData['uid'];
    } else {
      // this should work in every circumstance
      $cObj = $this->configurationManager->getContentObject();
      $uid = $cObj->data['uid'];
    }
    
    return $uid;
  }
}