How to identify sender from websocket (PHP) - websocket

Question

I try to build a website with WebSocket (JS+PHP) and i would like to get the socket from the sender. For example, if a client 'A' send a message to my server, how can I get the socket from the client 'A'.
I've search on google but the only thing i found is that socket_select wait for a communication and return the number of socket changed, but i can't get the socket itself.
My PHP code is below
<?php
$host = 'localhost'; //host
$port = '9000'; //port
$null = NULL; //null var
//Create TCP/IP sream socket
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
//reuseable port
socket_set_option($socket, SOL_SOCKET, SO_REUSEADDR, 1);
//bind socket to specified host
socket_bind($socket, 0, $port);
//listen to port
socket_listen($socket);
//create & add listning socket to the list
$sockets = array($socket);
$users = array();
$validActions = array('init');
//start endless loop, so that our script doesn't stop
while (true) {
//manage multipal connections
$changed = $sockets;
//returns the socket resources in $changed array
socket_select($changed, $null, $null, 0, 10);
//check for new socket
if (in_array($socket, $changed)) {
$socket_new = socket_accept($socket); //accept new socket
$sockets[] = $socket_new; //add socket to client array
$header = socket_read($socket_new, 1024); //read data sent by the socket
perform_handshaking($header, $socket_new, $host, $port); //perform websocket handshake
socket_getpeername($socket_new, $ip); //get ip address of connected socket
$response = mask(json_encode(array('type' => 'system', 'message' => $ip . ' connected'))); //prepare json data
send_message($response); //notify all users about new connection
//make room for new socket
$found_socket = array_search($socket, $changed);
unset($changed[$found_socket]);
}
$received_text = unmask($buf); //unmask data
$received_msg = json_decode($received_text); //json decode
//check for any incomming data
while (socket_recv($changed_socket, $buf, 1024, 0) >= 1) {
$received_text = unmask($buf); //unmask data
$tst_msg = json_decode($received_text); //json decode
// I HAVE TO GIVE $socket FROM THE CLIENT TO THE process() FUNCTION
process($received_msg);
... MORE CODE ....
}
}
// close the listening socket
socket_close($sock);

Answer 1

I think that I have to use socket_select, I've read the documentation but i still don't find to right way to get the socket from the sender of a message...