/**
* Negotiate permessage-deflate WebSocket extensio if supported by the clientn.
*
* @param HttpRequest $request
* @return PerMessageDeflate Or null when not supported by client / server or invalid window sizes are specified.
*/
protected function negotiatePerMessageDeflate(HttpRequest $request)
{
static $zlib;
$extension = null;
if ($zlib ?? ($zlib = \function_exists('inflate_init'))) {
foreach ($request->getHeaderTokens('Sec-WebSocket-Extensions') as $ext) {
if (\strtolower($ext->getValue()) === 'permessage-deflate') {
$extension = $ext;
break;
}
}
}
if ($extension === null) {
return;
}
try {
return PerMessageDeflate::fromHeaderToken($extension);
} catch (\OutOfRangeException $e) {
return;
}
}
/**
* Get the HTTP host as forwarded by a proxy.
*
* @param HttpRequest $request
* @return string Or null when no proxy header is found.
*/
public function getHost(HttpRequest $request)
{
foreach ($this->hostHeaders as $name) {
if ($request->hasHeader($name)) {
return $request->getHeaderTokens($name)[0]->getValue();
}
}
}
