main.c

std::vector<Player> players (MAX_CONNECTIONS);

// pull out the type of messages sent by our config
typedef server::message_ptr message_ptr;

// Define a callback to handle incoming messages
void on_message(server* s, websocketpp::connection_hdl hdl, message_ptr msg) {
    std::cout << "on_message called with hdl: " << hdl.lock().get()
              << " and message: " << msg->get_payload()
              << std::endl;

	// Craete player if there are no players
	if (players.size() == 0){
		// First PLayer
		players.push_back(Player(hdl, "#6666ff"));
	}

	else {
		// Check if player exists
		for (int i = 0; i < players.size(); i++) {
			if (players[i].GetConnection() == hdl) {
				std:: cout << "player exits: " << hdl.lock().get();
			}
		}
	}


    // check for a special command to instruct the server to stop listening so
    // it can be cleanly exited.
    if (msg->get_payload() == "stop-listening") {
        s->stop_listening();
        return;
    }

    try {
        s->send(hdl, msg->get_payload(), msg->get_opcode());
    } catch (const websocketpp::lib::error_code& e) {
        std::cout << "Echo failed because: " << e
                  << "(" << e.message() << ")" << std::endl;
    }
}

player.hpp

#ifndef PLAYER_H
#define PLAYER_H

#include <iostream>
#include <websocketpp/server.hpp>

#include "game.hpp"

class Player {
	private:
		Position pos;
		std::string color;
		websocketpp::connection_hdl con;

	public:
		Position GetPosition() {
			return pos;
		}

		void SetPosition(Position pos)
		{
			this->pos = pos;
		}

		websocketpp::connection_hdl GetConnection()
		{
			return con;
		}

		Player();

		Player(websocketpp::connection_hdl, std::string);
};

#endif