Need to publish based on incoming message

[rts-ssoundar619]

I have tried to publish a message from the message() function and I am getting this error.

function message($message) {
$client->publish('MCON', 'jkhajkdfadfm,jka jkhkadf jklhadf ', 0, false);
    //topic payload
    echo '\n';
    print_r($message->topic);
    echo '\n';
    $topic = explode('/', $message->topic);
    if (sizeof($topic) > 2) {
        $topic[2]($message->payload);
    } else {
        $topic[0]($message->payload);
    }
}

and I am getting the following error. Please help me to sort out the requirement.

Subscribed to a topic
PHP Notice:  Undefined variable: client in /var/www/html/test.php on line 35
PHP Fatal error:  Uncaught Error: Call to a member function publish() on null in /var/www/html/test.php:35
Stack trace:
#0 [internal function]: message(Object(Mosquitto\Message))
#1 /var/www/html/test.php(17): Mosquitto\Client->loopForever()
#2 {main}

thrown in /var/www/html/test.php on line 35
Thanks.

[1biot]

try this:

$client->onMessage(
    function ($message) using ($client) {
        $client->publish('MCON', 'jkhajkdfadfm,jka jkhkadf jklhadf ', 0, false);
        //topic payload
        echo '\n';
        print_r($message->topic);
        echo '\n';
        $topic = explode('/', $message->topic);
        if (sizeof($topic) > 2) {
            $topic[2]($message->payload);
        } else {
            $topic[0]($message->payload);
        }
    }
});