CheckHash::onBeforeAction

public function onBeforeAction(Event $event)
{
	foreach($this->action->getArguments() as $name => $argument)
	{
		if($argument instanceof Document)
		{
			$this->document = $argument;
		}
		elseif($name == 'hash')
		{
			$this->hash = $argument;
		}
	}

	if($this->document && $this->hash)
	{
		$link = ExternalLinkTable::getByHash($this->hash);
		if($link && $link['DOCUMENT_ID'] == $this->document->ID)
		{
			return null;
		}
	}

	$this->errorCollection[] = new Error(
		'Wrong hash', static::WRONG_HASH
	);
	return new EventResult(EventResult::ERROR, null, null, $this);
}