function HttpCache::validate

Validates that a cache entry is fresh.

The original request is used as a template for a conditional GET request with the backend.

Parameters

bool $catch Whether to process exceptions:

1 call to HttpCache::validate()

HttpCache::lookup in vendor/symfony/http-kernel/HttpCache/HttpCache.php

Lookups a Response from the cache for the given Request.

File

vendor/symfony/http-kernel/HttpCache/HttpCache.php, line 363

Class

HttpCache

Cache provides HTTP caching.

Namespace

Symfony\Component\HttpKernel\HttpCache

Code

protected function validate(Request $request, Response $entry, bool $catch = false) : Response {
    $subRequest = clone $request;
    // send no head requests because we want content
    if ('HEAD' === $request->getMethod()) {
        $subRequest->setMethod('GET');
    }
    // add our cached last-modified validator
    if ($entry->headers
        ->has('Last-Modified')) {
        $subRequest->headers
            ->set('If-Modified-Since', $entry->headers
            ->get('Last-Modified'));
    }
    // Add our cached etag validator to the environment.
    // We keep the etags from the client to handle the case when the client
    // has a different private valid entry which is not cached here.
    $cachedEtags = $entry->getEtag() ? [
        $entry->getEtag(),
    ] : [];
    $requestEtags = $request->getETags();
    if ($etags = array_unique(array_merge($cachedEtags, $requestEtags))) {
        $subRequest->headers
            ->set('If-None-Match', implode(', ', $etags));
    }
    $response = $this->forward($subRequest, $catch, $entry);
    if (304 == $response->getStatusCode()) {
        $this->record($request, 'valid');
        // return the response and not the cache entry if the response is valid but not cached
        $etag = $response->getEtag();
        if ($etag && \in_array($etag, $requestEtags, true) && !\in_array($etag, $cachedEtags, true)) {
            return $response;
        }
        $entry = clone $entry;
        $entry->headers
            ->remove('Date');
        foreach ([
            'Date',
            'Expires',
            'Cache-Control',
            'ETag',
            'Last-Modified',
        ] as $name) {
            if ($response->headers
                ->has($name)) {
                $entry->headers
                    ->set($name, $response->headers
                    ->get($name));
            }
        }
        $response = $entry;
    }
    else {
        $this->record($request, 'invalid');
    }
    if ($response->isCacheable()) {
        $this->store($request, $response);
    }
    return $response;
}