web socket example

server.php

<?php

session_start();

require 'constants.php';
require ROOTPATH . 'web-socket/WebSocket.php';
require ROOTPATH . 'libs/classes/DB.php';

$_SESSION['company_db'] = 'erp_clients';

$address = gethostbyname('localhost');
$port = '9000';

$socket = new WebSocket($address, $port, 0.1);

$socket->start();

socket.js

const address = '127.0.0.1';
    const port = '9000';
    let uri = "token=GhqMrFYIt2SH1bSaDTPa3x944v70kZ5CPAHs77jCpG37O1YSPlsRNdFR2TxP---1";

    const websocket = new WebSocket(`ws://${address}:${port}?${uri}`);

    websocket.onopen = (res) => {
        console.log(res.data);
    }

    websocket.onerror = (res) => {
        console.log('websocket.error');
        listGroups();
    };

    websocket.onclose = (res) => {
        console.log('websocket.onclose');
    };

    websocket.onmessage = (res) => {
        const response = JSON.parse(res.data);

        let selectGroup = document.querySelector('div[data-group-id="' + response.data[0].group_id + '"]');

        listGroups();
        if (selectGroup) {
            group_conversation_list(selectGroup);
        } else {
            if (selectGroup) {
                selectGroup = document.querySelector('div[data-group-id="' + response.data[0].group_id + '"]');
                group_conversation_list(selectGroup);
            }
        }
    };

WebSocket.php

<?php

class WebSocket
{
    private array $clients = [];

    private $server;

    private int $sleep = 0;

    public function __construct(string $address, int $port, int $sleep)
    {
        //Create TCP/IP stream socket
        if (!$server = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) {
            $error_code = socket_last_error();
            $error_message = socket_strerror($error_code);

            die("Couldn't create socket: [$error_code] $error_message \n");
        }
        echo "Socket: created ws://$address:$port \n";

        socket_set_option($server, SOL_SOCKET, SO_REUSEADDR, 1);

        //bind socket to specified host
        if (!socket_bind($server, $address, $port)) {
            $error_code = socket_last_error();
            $error_message = socket_strerror($error_code);

            die("Could not bind socket : [$error_code] $error_message \n");
        }
        echo "Socket: bind $address:$port \n";

        if (!socket_listen($server)) {
            $error_code = socket_last_error();
            $error_message = socket_strerror($error_code);

            die("Could not listen on socket : [$error_code] $error_message \n");
        }
        echo "Socket: listen $port \n";

        $this->server = $server;

        //create & add listening socket to the list
        $this->clients = [$this->server];

        $this->sleep = $sleep;
    }

    public function start(): void
    {
        try {
            //start endless loop, so that our script doesn't stop
            while (true) {
                // manage multiple connections
                $changed = $this->clients;

                // returns the socket resources in $changed array
                socket_select($changed, $write, $except, 1, 10);

                // check for new socket
                if (in_array($this->server, $changed)) {
                    $server_new = socket_accept($this->server); // accept new socket

                    $request = socket_read($server_new, 1024); //read data sent by the socket

                    $headers = $this->getHeaders($request);
                    $upgrade = $this->handshaking($headers); //perform websocket handshake
                    $ip = $this->getIP($server_new);

                    list($id, $authorizer, $token, $device_id) = self::AuthHeaders($request);

                    if ($token == NULL) {
                        echo 'Socket: denied ' . $ip . ' because not have [Authorization Token] ' . PHP_EOL;
                    } /*else if ($device_id == NULL) {
                        echo 'Socket: denied ' . $ip . ' because not have [Device Token] ' . PHP_EOL;
                    } */ else if ($this->approved($id, $authorizer, $token, $device_id) === true) {

                        $this->clients[$id] = $server_new; // add socket to client array
                        @socket_write($server_new, $upgrade, strlen($upgrade));

                        // notify all users about new connection
                        $this->send('system', [$ip . ' connected'], $this->clients);

                        echo 'Socket: Connect ' . $ip . ' with auth-token ' . $id . PHP_EOL;

                    } else {
                        echo 'Socket: denied ' . $ip . ' with auth-token ' . ((string)$id) . PHP_EOL;
                    }

                    // make room for new socket
                    $found_socket = array_search($this->server, $changed);
                    unset($changed[$found_socket]);
                }

                // loop through all connected sockets
                foreach ($changed as $token => $changed_socket) {
                    // check for any incoming data
                    while (socket_recv($changed_socket, $buf, 1024, 0) >= 1) {
                        //prepare data to be sent to client
                        $client_res = json_decode($this->unmask($buf));
                        if (($client_res->receiver_to ?? false) && isset($client_res->data)) {

                            $client_res->receiver_to = array_unique((array)$client_res->receiver_to);
                            if (($req_collection = array_intersect_key($this->clients, array_flip($client_res->receiver_to))) !== []) {
                                $this->send('client', [$client_res->data], $req_collection);
                            } else {
                                echo 'Socket: not send data ' . PHP_EOL;
                            }

                        } else {
                            $this->send('system', ['{"receiver_to": ["###id","###id",...],"data": [...]}'], [$this->clients[$token]]);
                            echo 'Socket: not set sender information attribute' . PHP_EOL;
                        }
                        break 2;
                    }

                    $buf = @socket_read($changed_socket, 1024, PHP_NORMAL_READ);
                    if ($buf === false) {

                        // remove client for $clients array
                        $found_socket = array_search($changed_socket, $this->clients);

                        $ip = $this->getIP($changed_socket);

                        unset($this->clients[$found_socket]);

                        // notify all users about disconnected connection
                        $this->send('system', [$ip . 'disconnected'], $this->clients);
                        echo 'Socket: sleep socket for ' . $ip . PHP_EOL;
                    }

                    echo 'Socket: socket is running ' . PHP_EOL;
                    echo 'Socket: selected ' . count($changed) . PHP_EOL;
                }

                //echo 'Socket: listing ' . count($this->clients) . PHP_EOL;
                sleep($this->sleep);
            }
        } catch (Exception $e) {
            echo $e->getMessage();
            socket_close($this->server);
        }
    }

    private function send(string $type, array $response, array $clients): void
    {
        $msg = $this->mask($type, $response);

        foreach ($clients as $token => $changed_socket) {
            @socket_write($changed_socket, $msg, strlen($msg));
            echo 'Socket: sending... data to ' . $token . PHP_EOL;
        }
    }

    // Unmask incoming framed message
    private function unmask(string $buffer): string
    {
        $length = ord($buffer[1]) & 127;
        if ($length == 126) {
            $masks = substr($buffer, 4, 4);
            $data = substr($buffer, 8);
        } elseif ($length == 127) {
            $masks = substr($buffer, 10, 4);
            $data = substr($buffer, 14);
        } else {
            $masks = substr($buffer, 2, 4);
            $data = substr($buffer, 6);
        }
        $buffer = '';
        for ($i = 0; $i < strlen($data); ++$i) {
            $buffer .= $data[$i] ^ $masks[$i % 4];
        }
        return $buffer;
    }

    // Encode message for transfer to client.
    private function mask(string $type, array $response): string
    {
        $b1 = 0x80 | (0x1 & 0x0f);
        $res = json_encode(['type' => $type, 'data' => $response]);
        $length = strlen($res);

        if ($length <= 125)
            $header = pack('CC', $b1, $length);
        elseif ($length > 125 && $length < 65536)
            $header = pack('CCn', $b1, 126, $length);
        elseif ($length >= 65536)
            $header = pack('CCNN', $b1, 127, $length);

        return $header . $res;
    }

    public function getHeaders(string $received_header): array
    {
        $lines = preg_split("/\r\n/", $received_header);
        foreach ($lines as $line) {
            $line = chop($line);
            if (preg_match('/\A(\S+): (.*)\z/', $line, $matches)) {
                $headers[$matches[1]] = $matches[2];
            }
        }

        return $headers ?? [];
    }

    private function handshaking($received_header): string
    {
        $secKey = $received_header['Sec-WebSocket-Key'] ?? '';
        $secAccept = base64_encode(pack('H*', sha1($secKey . '258EAFA5-E914-47DA-95CA-C5AB0DC85B11')));
        //hand shaking header
        return "HTTP/1.1 101 Web Socket Protocol Handshake\r\n" .
            "Upgrade: websocket\r\n" .
            "Connection: Upgrade\r\n" .
            "Sec-WebSocket-Accept:$secAccept\r\n\r\n";
    }

    private function getIP(Socket $socket)
    {
        socket_getpeername($socket, $ip);
        return $ip;
    }

    function approved(string $id, string $authorizer, string $token, string $device_id = null)
    {
        $allow_user_privilege = [
            '####' => 'customers',
            '###' => 'employee_master',
        ];

        $table = $allow_user_privilege[$authorizer] ?? false;

        try {
            $_SESSION['company_db'] = 'erp_clients';
            $db = new DB();

            $db_name = $db->getRecord("select `db_name` from `tokens` where `token` = '$token'");

            $_SESSION['company_db'] = $db_name['db_name'];
            $db = new DB();

            $id = str_replace('#', '', $id);
            $in_user = $db->getRecord("select sno from `$table` where `sno` = '$id'");

            if ($in_user['sno'] ?? false)
                return true;

        } catch (Exception $e) {
            echo $e->getMessage() . PHP_EOL;
            return false;
        }

        return false;
    }

    public function AuthHeaders(string $request): array
    {
        // if incoming request have headers
        $headers = $this->getHeaders($request);

        if (isset($headers['token'])) {
            $token = $headers['token'] ?? '';

            preg_match('([#]+[0-9]+)', $token, $id);
            $token = str_replace($id[0], '', $token);

            preg_match('/([#]+)/', $id[0], $authorizer);

            return [$id[0] ?? null, $authorizer[0] ?? null, $token ?? null, $headers['device_id'] ?? null];
        }

        // if incoming request have query-string
        preg_match('/token=([^(&\s)]*)/', $request, $client_token);
        preg_match('/device_id=([^(&\s)]*)/', $request, $device_id);

        if ($client_token[1] ?? false) {
            preg_match('([-]+[0-9]+)', $client_token[1], $id);

            $token = str_replace($id[0], '', $client_token[1]);

            preg_match('([-]+)', $id[0], $authorizer);

            $id = str_replace('-', '#', $id[0] ?? '');
            $authorizer = str_replace('-', '#', $authorizer[0] ?? '');
        }

        return [$id ?? null, $authorizer ?? null, $token ?? null, $device_id[1] ?? null];
    }
}