how to get socket_read value to plain text sent from javascript in PHP websocket

Question

i am trying to make my small websocket php class in which i wanted to make functions like onopen onmessage etc like node js [i know there are other libraries out there but i wanted to learn it myself].so far i am able to successfully recieve message from js websocket to php with this code below

<?php 
$host = "localhost";
$port = 8001;
$sockets=array();

function sendAll($connections,$msg){
    foreach ($connections as $each) {
        send($each,$msg);
    }
}

function send($client,$msg){
    $msg = chr(129) . chr(strlen($msg)) . $msg;
    socket_write($client,$msg,strlen($msg));
}


function handshake($client){
    $request = socket_read($client, 5000);
    preg_match('#Sec-WebSocket-Key: (.*)
#', $request, $matches);
    $key = base64_encode(pack(
        'H*',
        sha1($matches[1] . '258EAFA5-E914-47DA-95CA-C5AB0DC85B11')
    ));
    $headers = "HTTP/1.1 101 Switching Protocols
";
    $headers .= "Upgrade: websocket
";
    $headers .= "Connection: Upgrade
";
    $headers .= "Sec-WebSocket-Version: 13
";
    $headers .= "Sec-WebSocket-Accept: $key

";
    socket_write($client, $headers, strlen($headers));
}

// Create WebSocket.
$server = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_set_option($server, SOL_SOCKET, SO_REUSEADDR, 1);
socket_set_nonblock($server);
socket_bind($server, $host, $port);
socket_listen($server);    


while(true){

    $client = socket_accept($server);
    if($client != false){
        usleep(100);
        handshake($client);
        array_push($sockets,$client);
        print_r($sockets); 
    }
    else{
        if(count($sockets) > 0){
            foreach ($sockets as $each) {
                $msg = socket_read($each,5000);
                if($msg != false){
                    filter($msg);
                    // send($each,"testing");
                }
            }
        }
    }


}



function filter($msg){
    $msg = unpack("c*",$msg);
    foreach ($msg as $value) {
        echo chr($value);
    }
    // print_r($msg);
}
?>

after some research i found that websocket sends message in binary. i cant convert that message into plain text. i dont know which language or format that data is sent into.tell me please which format is it and how to read it as plain text sample picture below

question from:https://stackoverflow.com/questions/65644666/how-to-get-socket-read-value-to-plain-text-sent-from-javascript-in-php-websocket

Answer 1

finally i find the way to decode from this website

its actually masked which needed to be unmasked . here i found a function from a website all i have to do is to read that scarmled text is unmask with below custom function

function unmask($text) {
    $length = ord($text[1]) & 127;
    if($length == 126) {
    $masks = substr($text, 4, 4);
    $data = substr($text, 8);
    }
    elseif($length == 127) {
    $masks = substr($text, 10, 4);
    $data = substr($text, 14);
    }
    else {
    $masks = substr($text, 2, 4);
    $data = substr($text, 6);
    }
    $text = "";
    for ($i = 0; $i < strlen($data); ++$i) {
    $text .= $data[$i] ^ $masks[$i%4];
    }
    return $text;
    }