/** * Check if a cache response satisfies a request's caching constraints * * @param RequestInterface $request Request to validate * @param Response $response Response to validate * * @return bool */ public function canResponseSatisfyRequest(RequestInterface $request, Response $response) { $responseAge = $response->calculateAge(); $reqc = $request->getHeader('Cache-Control'); $resc = $response->getHeader('Cache-Control'); // Check the request's max-age header against the age of the response if ($reqc && $reqc->hasDirective('max-age') && $responseAge > $reqc->getDirective('max-age')) { return false; } // Check the response's max-age header if ($response->isFresh() === false) { $maxStale = $reqc ? $reqc->getDirective('max-stale') : null; if (null !== $maxStale) { if ($maxStale !== true && $response->getFreshness() < -1 * $maxStale) { return false; } } elseif ($resc && $resc->hasDirective('max-age') && $responseAge > $resc->getDirective('max-age')) { return false; } } if ($this->revalidation->shouldRevalidate($request, $response)) { try { return $this->revalidation->revalidate($request, $response); } catch (CurlException $e) { $request->getParams()->set('cache.hit', 'error'); return $this->canResponseSatisfyFailedRequest($request, $response); } } return true; }
/** * Check if a cache response satisfies a request's caching constraints * * @param RequestInterface $request Request to validate * @param Response $response Response to validate * * @return bool */ public function canResponseSatisfyRequest(RequestInterface $request, Response $response) { $responseAge = $response->calculateAge(); $reqc = $request->getHeader('Cache-Control'); $resc = $response->getHeader('Cache-Control'); // Check the request's max-age header against the age of the response if ($reqc && $reqc->hasDirective('max-age') && $responseAge > $reqc->getDirective('max-age')) { return false; } // Check the response's max-age header if ($response->isFresh() === false) { $maxStale = $reqc ? $reqc->getDirective('max-stale') : null; if (null !== $maxStale) { if ($maxStale !== true && $response->getFreshness() < -1 * $maxStale) { return false; } } elseif ($resc && $resc->hasDirective('max-age') && $responseAge > $resc->getDirective('max-age')) { return false; } } // Only revalidate GET requests if ($request->getMethod() == RequestInterface::GET) { // Check if the response must be validated against the origin server if ($request->getHeader('Pragma') == 'no-cache' || $reqc && ($reqc->hasDirective('no-cache') || $reqc->hasDirective('must-revalidate')) || $resc && ($resc->hasDirective('no-cache') || $resc->hasDirective('must-revalidate'))) { // no-cache: When no parameters are present, always revalidate // When parameters are present in no-cache and the request includes those same parameters, then the // response must re-validate. I'll need an example of what fields look like in order to implement a // smarter version of no-cache // Requests can decline to revalidate against the origin server by setting the cache.revalidate param: // - never - To never revalidate and always contact the origin server // - skip - To skip revalidation and just use what is in cache switch ($request->getParams()->get('cache.revalidate')) { case 'never': return false; case 'skip': return true; default: return $this->revalidation->revalidate($request, $response); } } } return true; }