WebSockets

Introduction#

Usage of socket extension implements a low-level interface to the socket communication functions based on the popular BSD sockets, providing the possibility to act as a socket server as well as a client.

Simple TCP/IP server

Minimal example based on PHP manual example found here: https://php.net/manual/en/sockets.examples.php

Create a websocket script that listens to Port 5000 Use putty, terminal to run telnet 127.0.0.1 5000 (localhost). This script replies with the message you sent (as a ping-back)

<?php
set_time_limit(0); // disable timeout
ob_implicit_flush(); // disable output caching 

// Settings    
$address = '127.0.0.1';
$port = 5000;


/*
    function socket_create ( int $domain , int $type , int $protocol )
    $domain can be AF_INET, AF_INET6 for IPV6 , AF_UNIX for Local communication protocol
    $protocol can be SOL_TCP, SOL_UDP  (TCP/UDP)
    @returns true on success
*/

if (($socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) === false) {
    echo "Couldn't create socket".socket_strerror(socket_last_error())."\n";
}


/*
    socket_bind ( resource $socket , string $address [, int $port = 0 ] )
    Bind socket to listen to address and port
*/

if (socket_bind($socket, $address, $port) === false) {
    echo "Bind Error ".socket_strerror(socket_last_error($sock)) ."\n";
}

if (socket_listen($socket, 5) === false) {
    echo "Listen Failed ".socket_strerror(socket_last_error($socket)) . "\n";
}

do {
    if (($msgsock = socket_accept($socket)) === false) {
        echo "Error: socket_accept: " . socket_strerror(socket_last_error($socket)) . "\n";
        break;
    }

    /* Send Welcome message. */
    $msg = "\nPHP Websocket \n";

    // Listen to user input
    do {
        if (false === ($buf = socket_read($msgsock, 2048, PHP_NORMAL_READ))) {
            echo "socket read error: ".socket_strerror(socket_last_error($msgsock)) . "\n";
            break 2;
        }
        if (!$buf = trim($buf)) {
            continue;
        }

        // Reply to user with their message
        $talkback = "PHP: You said '$buf'.\n";
        socket_write($msgsock, $talkback, strlen($talkback));
        // Print message in terminal
        echo "$buf\n";
        
    } while (true);
    socket_close($msgsock);
} while (true);

socket_close($socket);
?>