public function lookup(Request
$request): ?Response
{ $key =
$this->
getCacheKey($request);
if (!
$entries =
$this->
getMetadata($key)) { return null;
} // find a cached entry that matches the request.
$match = null;
foreach ($entries as $entry) { if ($this->
requestsMatch(isset($entry[1
]['vary'
][0
]) ?
implode(', ',
$entry[1
]['vary'
]) : '',
$request->headers->
all(),
$entry[0
])) { $match =
$entry;
break;
} } if (null ===
$match) { return null;
} $headers =
$match[1
];