function HttpCache::lookup

Lookups a Response from the cache for the given Request.

When a matching cache entry is found and is fresh, it uses it as the response without forwarding any request to the backend. When a matching cache entry is found but is stale, it attempts to "validate" the entry with the backend using conditional GET. When no matching cache entry is found, it triggers "miss" processing.

Parameters

bool $catch Whether to process exceptions:

Throws

\Exception

2 calls to HttpCache::lookup()

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

Handles a Request to convert it to a Response.

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

Locks a Request during the call to the backend.

File

vendor/symfony/http-kernel/HttpCache/HttpCache.php, line 318

Class

HttpCache

Cache provides HTTP caching.

Namespace

Symfony\Component\HttpKernel\HttpCache

Code

protected function lookup(Request $request, bool $catch = false) : Response {
    try {
        $entry = $this->store
            ->lookup($request);
    } catch (\Exception $e) {
        $this->record($request, 'lookup-failed');
        if ($this->options['debug']) {
            throw $e;
        }
        return $this->pass($request, $catch);
    }
    if (null === $entry) {
        $this->record($request, 'miss');
        return $this->fetch($request, $catch);
    }
    if (!$this->isFreshEnough($request, $entry)) {
        $this->record($request, 'stale');
        return $this->validate($request, $entry, $catch);
    }
    if ($entry->headers
        ->hasCacheControlDirective('no-cache')) {
        return $this->validate($request, $entry, $catch);
    }
    $this->record($request, 'fresh');
    $entry->headers
        ->set('Age', $entry->getAge());
    return $entry;
}