function ResponseHeaderBag::computeCacheControlValue

Returns the calculated value of the cache-control header.

This considers several other headers and calculates or modifies the cache-control header to a sensible, conservative value.

1 call to ResponseHeaderBag::computeCacheControlValue()

ResponseHeaderBag::set in vendor/symfony/http-foundation/ResponseHeaderBag.php

Sets a header by name.

File

vendor/symfony/http-foundation/ResponseHeaderBag.php, line 243

Class

ResponseHeaderBag

ResponseHeaderBag is a container for Response HTTP headers.

Namespace

Symfony\Component\HttpFoundation

Code

protected function computeCacheControlValue() : string {
    if (!$this->cacheControl) {
        if ($this->has('Last-Modified') || $this->has('Expires')) {
            return 'private, must-revalidate';
            // allows for heuristic expiration (RFC 7234 Section 4.2.2) in the case of "Last-Modified"
        }
        // conservative by default
        return 'no-cache, private';
    }
    $header = $this->getCacheControlHeader();
    if (isset($this->cacheControl['public']) || isset($this->cacheControl['private'])) {
        return $header;
    }
    // public if s-maxage is defined, private otherwise
    if (!isset($this->cacheControl['s-maxage'])) {
        return $header . ', private';
    }
    return $header;
}