private function upgradeTransport()
{
$query = ['sid' => $this->session->id, 'EIO' => $this->options['version'], 'use_b64' => $this->options['use_b64'], 'transport' => static::TRANSPORT_WEBSOCKET];
$url = sprintf('/%s/?%s', trim($this->url['path'], '/'), http_build_query($query));
$key = base64_encode(sha1(uniqid(mt_rand(), true), true));
$origin = '*';
$headers = isset($this->context['headers']) ? (array) $this->context['headers'] : [];
foreach ($headers as $header) {
$matches = [];
if (preg_match('`^Origin:\\s*(.+?)$`', $header, $matches)) {
$origin = $matches[1];
break;
}
}
$request = "GET {$url} HTTP/1.1\r\n" . "Host: {$this->url['host']}\r\n" . "Upgrade: WebSocket\r\n" . "Connection: Upgrade\r\n" . "Sec-WebSocket-Key: {$key}\r\n" . "Sec-WebSocket-Version: 13\r\n" . "Origin: {$origin}\r\n";
if (!empty($this->cookies)) {
$request .= "Cookie: " . implode('; ', $this->cookies) . "\r\n";
}
$request .= "\r\n";
fwrite($this->stream, $request);
$result = fread($this->stream, 12);
if ('HTTP/1.1 101' !== $result) {
throw new UnexpectedValueException(sprintf('The server returned an unexpected value. Expected "HTTP/1.1 101", had "%s"', $result));
}
// cleaning up the stream
while ('' !== trim(fgets($this->stream))) {
}
$this->write(EngineInterface::UPGRADE);
//remove message '40' from buffer, emmiting by socket.io after receiving EngineInterface::UPGRADE
$this->read();
}
