/**
* 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 = $response->getAge();
// Check the request's max-age header against the age of the response
if ($request->hasCacheControlDirective('max-age') && $responseAge > $request->getCacheControlDirective('max-age')) {
return false;
}
// Check the response's max-age header
if ($response->isFresh() === false) {
$maxStale = $request->getCacheControlDirective('max-stale');
if (null !== $maxStale) {
if ($maxStale !== true && $response->getFreshness() < -1 * $maxStale) {
return false;
}
} elseif ($response->hasCacheControlDirective('max-age') && $responseAge > $response->getCacheControlDirective('max-age')) {
return false;
}
}
// Only revalidate GET requests
if ($request->getMethod() == RequestInterface::GET) {
// Check if the response must be validated against the origin server
if ($request->getHeader('Pragma') == 'no-cache' || $request->hasCacheControlDirective('no-cache') || $request->hasCacheControlDirective('must-revalidate') || $response->hasCacheControlDirective('must-revalidate') || $response->hasCacheControlDirective('no-cache')) {
// no-cache: When no parameters are present, always revalidate
// When parameters are present in no-cache and the request includes those same parameters, then the
// response must re-validate. I'll need an example of what fields look like in order to implement a
// smarter version of no-cache
// Requests can decline to revalidate against the origin server by setting the cache.revalidate param:
// - never - To never revalidate and always contact the origin server
// - skip - To skip revalidation and just use what is in cache
switch ($request->getParams()->get('cache.revalidate')) {
case 'never':
return false;
case 'skip':
return true;
default:
return $this->revalidation->revalidate($request, $response);
}
}
}
return true;
}
/**
* @covers Guzzle\Http\Message\Response::getFreshness
* @covers Guzzle\Http\Message\Response::isFresh
*/
public function testCalculatesFreshness()
{
$response = new Response(200);
$this->assertNull($response->isFresh());
$this->assertNull($response->getFreshness());
$response->addCacheControlDirective('max-age', 120);
$response->setHeader('Age', 100);
$this->assertEquals(20, $response->getFreshness());
$this->assertTrue($response->isFresh());
$response->setHeader('Age', 150);
$this->assertEquals(-30, $response->getFreshness());
$this->assertFalse($response->isFresh());
}
/**
* Add the plugin's headers to a response
*
* @param RequestInterface $request Request
* @param Response $response Response to add headers to
*/
protected function addResponseHeaders(RequestInterface $request, Response $response)
{
$params = $request->getParams();
$response->setHeader('Via', sprintf('%s GuzzleCache/%s', $request->getProtocolVersion(), Version::VERSION));
$lookup = ($params['cache.lookup'] === true ? 'HIT' : 'MISS') . ' from GuzzleCache';
if ($header = $response->getHeader('X-Cache-Lookup')) {
// Don't add duplicates
$values = $header->toArray();
$values[] = $lookup;
$response->setHeader('X-Cache-Lookup', array_unique($values));
} else {
$response->setHeader('X-Cache-Lookup', $lookup);
}
if ($params['cache.hit'] === true) {
$xcache = 'HIT from GuzzleCache';
} elseif ($params['cache.hit'] == 'error') {
$xcache = 'HIT_ERROR from GuzzleCache';
} else {
$xcache = 'MISS from GuzzleCache';
}
if ($header = $response->getHeader('X-Cache')) {
// Don't add duplicates
$values = $header->toArray();
$values[] = $xcache;
$response->setHeader('X-Cache', array_unique($values));
} else {
$response->setHeader('X-Cache', $xcache);
}
if ($response->isFresh() === false) {
$response->addHeader('Warning', sprintf('110 GuzzleCache/%s "Response is stale"', Version::VERSION));
if ($params['cache.hit'] === 'error') {
$response->addHeader('Warning', sprintf('111 GuzzleCache/%s "Revalidation failed"', Version::VERSION));
}
}
}
/**
* Add the plugin's headers to a response
*
* @param string $cacheKey Cache key
* @param RequestInterface $request Request
* @param Response $response Response to add headers to
*/
protected function addResponseHeaders($cacheKey, RequestInterface $request, Response $response)
{
if (!$response->hasHeader('X-Guzzle-Cache')) {
$response->setHeader('X-Guzzle-Cache', "key={$cacheKey}");
}
$response->addHeader('Via', sprintf('%s GuzzleCache/%s', $request->getProtocolVersion(), Version::VERSION));
if ($this->debugHeaders) {
if ($request->getParams()->get('cache.lookup') === true) {
$response->addHeader('X-Cache-Lookup', 'HIT from GuzzleCache');
} else {
$response->addHeader('X-Cache-Lookup', 'MISS from GuzzleCache');
}
if ($request->getParams()->get('cache.hit') === true) {
$response->addHeader('X-Cache', 'HIT from GuzzleCache');
} elseif ($request->getParams()->get('cache.hit') === 'error') {
$response->addHeader('X-Cache', 'HIT_ERROR from GuzzleCache');
} else {
$response->addHeader('X-Cache', 'MISS from GuzzleCache');
}
}
if ($response->isFresh() === false) {
$response->addHeader('Warning', sprintf('110 GuzzleCache/%s "Response is stale"', Version::VERSION));
if ($request->getParams()->get('cache.hit') === 'error') {
$response->addHeader('Warning', sprintf('111 GuzzleCache/%s "Revalidation failed"', Version::VERSION));
}
}
}
