stream.php

<?php
/** @noinspection PhpUnhandledExceptionInspection */

use App\MboxReader;

include(__DIR__ . "/src/init.php");

$mboxPath = '/var/mail/root';

$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_set_option($socket, SOL_SOCKET, SO_REUSEADDR, 1);
socket_bind($socket, '0.0.0.0', 81);
socket_listen($socket);

while ($connection = socket_accept($socket)) {
    $pid = pcntl_fork();
    if ($pid === -1) {
        exit("Could not fork");
    } elseif ($pid) {
        echo "Created child process $pid\n";
        continue;
    } else {
        echo "Accepted new connection\n";
        break;
    }
}

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

$f = null;
$reader = new MboxReader();
if (!file_exists($mboxPath)) {
    file_put_contents($mboxPath, '');
    chmod($mboxPath, 0666);
}

function frame($message): string
{
    $frame = chr(129);
    if (strlen($message) < 126) {
        $frame .= chr(strlen($message));
    } elseif (strlen($message) < 2 ** 16) {
        $frame .= chr(126) . pack('n', strlen($message));
    } else {
        $frame .= chr(127) . pack('Q', strlen($message));
    }
    $frame .= $message;
    return $frame;
}

$messages = $reader->read($mboxPath);
$result = socket_write($connection, frame(json_encode($messages)));
if ($result === false) throw new Exception("Write error");

while (true) {
    exec("inotifywait -e modify -e create ${mboxPath}", $_, $return);
    if ($return !== 0) continue;

    $messages = $reader->read($mboxPath);

    $result = socket_write($connection, frame(json_encode($messages)));
    if ($result === false) throw new Exception("Write error");
}

socket_close($connection);