protected function computeCacheControlValue()
    {
        if (!$this->cacheControl && !$this->has('ETag') && !$this->has('Last-Modified') && !$this->has('Expires')) {
            return 'no-cache, private';
        }

        if (!$this->cacheControl) {
            // conservative by default
            return 'private, must-revalidate';
        }

        $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 $header;
    }
protected function computeCacheControlValue()
    {
        if (!$this->cacheControl && !$this->has('ETag') && !$this->has('Last-Modified') && !$this->has('Expires')) {
            return 'no-cache, private';
        }

        if (!$this->cacheControl) {
            // conservative by default
            return 'private, must-revalidate';
        }

        $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;
    }
protected function computeCacheControlValue ( ) { if ( ! $ this -> cacheControl && ! $ this -> has ( 'ETag' ) && ! $ this -> has ( 'Last-Modified' ) && ! $ this -> has ( 'Expires' ) ) { return 'no-cache, private' ; } if ( ! $ this -> cacheControl ) { // conservative by default return 'private, must-revalidate' ; } $ 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 ; }
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.

@return string
Returns the calculated value of the cache - control header .