sockets

<?php
function echoClients(array $clients) {
    if (count($clients) == 0) {
        echo "No clients connected.\n";
        return;
    }
    $names = array();
    foreach ($clients as $client) {
        if (!is_null($client['name']))
            $names[] = $client['name'];
    }
    echo "Clients connected: ".implode(', ', $names).".\n";
}
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_bind($socket, '127.0.0.1', 100);
socket_listen($socket);
$clients = array();
while (true) {
    $read = array($socket);
    foreach ($clients as $client) {
        $read[] = $client['socket'];
    }
    $ready = socket_select($read, $write = null, $except = null, null);
    if (in_array($socket, $read, true)) {
        $clients[] = array(
            'socket' => socket_accept($socket),
            'name' => null
        );
        socket_write($clients[count($clients)-1]['socket'], "Welcome to ChatServer!\nWrite your name: ");
        $ready--;
    }
    if ($ready == 0) continue;
    $num_clients = count($clients);
    for ($i = 0; $i < $num_clients; $i++) {
        if (in_array($clients[$i]['socket'], $read, true)) {
            $input = socket_read($clients[$i]['socket'], 256);
            if (empty($input)) {
                socket_close($clients[$i]['socket']);
                echo "--{$clients[$i]['name']} has left. ";
                unset($clients[$i]);
                echoClients($clients);
            }
            else {
                if (is_null($clients[$i]['name'])) {
                    $clients[$i]['name'] = trim(preg_replace('/\s/', ' ', $input));
                    echo "--{$clients[$i]['name']} has joined. ";
                    echoClients($clients);
                }
                else {
                    echo "{$clients[$i]['name']} says: $input";
                }
            }
        }
    }
    $clients = array_merge(array(), $clients);
}
socket_close($socket);
?>