/**
* Attempts to cache the sent entity by its last modification date.
* @param string|int|DateTime last modified time
* @param string strong entity tag validator
* @return bool
*/
public function isModified($lastModified = NULL, $etag = NULL)
{
if ($lastModified) {
$this->response->setHeader('Last-Modified', $this->response->date($lastModified));
}
if ($etag) {
$this->response->setHeader('ETag', '"' . addslashes($etag) . '"');
}
$ifNoneMatch = $this->request->getHeader('If-None-Match');
if ($ifNoneMatch === '*') {
$match = TRUE; // match, check if-modified-since
} elseif ($ifNoneMatch !== NULL) {
$etag = $this->response->getHeader('ETag');
if ($etag == NULL || strpos(' ' . strtr($ifNoneMatch, ",\t", ' '), ' ' . $etag) === FALSE) {
return TRUE;
} else {
$match = TRUE; // match, check if-modified-since
}
}
$ifModifiedSince = $this->request->getHeader('If-Modified-Since');
if ($ifModifiedSince !== NULL) {
$lastModified = $this->response->getHeader('Last-Modified');
if ($lastModified != NULL && strtotime($lastModified) <= strtotime($ifModifiedSince)) {
$match = TRUE;
} else {
return TRUE;
}
}
if (empty($match)) {
return TRUE;
}
$this->response->setCode(IHttpResponse::S304_NOT_MODIFIED);
return FALSE;
}