CheckChatAccess.php

<?php
 
namespace Bitrix\Im\V2\Controller\Filter;
 
use Bitrix\Im\V2\Chat;
use Bitrix\Im\V2\Message;
use Bitrix\Im\V2\MessageCollection;
use Bitrix\Main\Engine\ActionFilter\Base;
use Bitrix\Main\Event;
use Bitrix\Main\EventResult;
 
class CheckChatAccess extends Base
{
    public function onBeforeAction(Event $event)
    {
        if (!$this->hasAccess())
        {
            $this->addError(new Chat\ChatError(Chat\ChatError::ACCESS_DENIED));
 
            return new EventResult(EventResult::ERROR, null, null, $this);
        }
 
        return null;
    }
 
    private function hasAccess(): bool
    {
        foreach ($this->getAction()->getArguments() as $argument)
        {
            if ($argument instanceof Message)
            {
                return $argument->getChat()->hasAccess();
            }
            if ($argument instanceof MessageCollection)
            {
                return $this->hasAccessToMessages($argument);
            }
            if ($argument instanceof Chat)
            {
                return $argument->hasAccess();
            }
        }
 
        return true;
    }
 
    private function hasAccessToMessages(MessageCollection $messages): bool
    {
        $commonChatId = $messages->getCommonChatId();
 
        if ($commonChatId !== null)
        {
            return Chat::getInstance($commonChatId)->hasAccess();
        }
 
        foreach ($messages as $message)
        {
            if (!$message->getChat()->hasAccess())
            {
                return false;
            }
        }
 
        return true;
    }
}