How to send command to player who clicked on another player?

How to send a command or event to the player who clicked on another player? Maybe DataPacketReceiveEvent ,can send me an example code?

 

PHP:

public function onInteract(EntityDamageEvent $event) {
    if($event instanceof EntityDamageByEntityEvent and $event->getEntity() instanceof Player and $event->getDamager() instanceof Player) {
        $this->getServer()->dispatchCommand($event->getPlayer(), "command to run here");
    }
}

 

Can you give me an example whit DataPacketSend? because i have whit EntityDamage cancelled on the world.

 

The event function should still be called even if the event is cancelled

 

It has an method to cancel players to pvp in each world and when click send this command?