library/Rediska/PubSub/Connections.php
public function hasChannel($channel)
    {
        $connection = $this->getConnectionByChannelName($channel);

        return isset($this->_channelsByConnections[$connection->getAlias()])
            && in_array($channel, $this->_channelsByConnections[$connection->getAlias()]);
    }
public function hasChannel($channel)
    {
        $connection = $this->getConnectionByChannelName($channel);

        return isset($this->_channelsByConnections[$connection->getAlias()])
            && in_array($channel, $this->_channelsByConnections[$connection->getAlias()]);
    }
Has channel?

@param string $channel
@return boolean