itstructure / yii2-template-multilanguage

     *

     * @return $this

     */

    public function setExpires(\DateTime $date = null)

    {

        if (null === $date) {

            $this->headers->remove('Expires');

        } else {

            $date = clone $date;

            $date->setTimezone(new \DateTimeZone('UTC'));

            $this->headers->set('Expires', $date->format('D, d M Y H:i:s').' GMT');

        }

        return $this;

    }

    /**

     * Returns the number of seconds after the time specified in the response's Date

     *

     * @return $this

     */

    public function setLastModified(\DateTime $date = null)

    {

        if (null === $date) {

            $this->headers->remove('Last-Modified');

        } else {

            $date = clone $date;

            $date->setTimezone(new \DateTimeZone('UTC'));

            $this->headers->set('Last-Modified', $date->format('D, d M Y H:i:s').' GMT');

        }

        return $this;

    }

    /**

     * Returns the literal value of the ETag HTTP header.