async.php

<?php

// async php client
$request = '';
$request .= "GET / HTTP/1.1\r\n";
$request .= "Host: google.com\r\n";
$request .= "Connection: Close\r\n\r\n";

$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_set_nonblock($socket);

$waited  = 0;
$timeout = 1000;
while (true) {
    @socket_connect($socket, 'google.com', 80);
    $error = socket_last_error();
    //echo $error . '=>' . socket_strerror($error) . PHP_EOL;
    if ($error == SOCKET_EINPROGRESS || $error == SOCKET_EALREADY) {
        usleep(5);
        $waited += 5;
        if ($waited > $timeout) {
            throw new RuntimeException('Timeout reached , waited ' . $waited . 'ms');
        }
        continue;
    }
    if ($error == SOCKET_EISCONN) {
        echo 'connected after ' . $waited . 'ms' . PHP_EOL;
        break;
    }
    throw new RuntimeException('unknown error ' . $error . ':' . socket_strerror($error));
}
socket_write($socket, $request);
socket_close($socket);