/**
* Sets http headers for proper caching with 304-code according to the file's change data.
*
* @param ojbect $fileObject the fileObject who's change date should be compared against the
* browser's cache-timestsamp
*
* @return bool indicating if file is cached in browser
*/
private function _setHttpCacheHeaders($fileObject)
{
# Do not force 304 caching if disabled by config
if (static::$_aggressiveCaching !== true) {
return false;
}
# Collect some information about file requested and file in browser's cache
$fileModifiedTimestamp = $fileObject->getMTime();
$fileName = $fileObject->getFileName();
$browserModifiedTimestamp = isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) ? strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) : null;
# Makes the browser respond with HTTP_IF_MODIFIED_SINCE and If-None-Match for E-Tag validation
header('Last-Modified: ' . gmdate("D, d M Y H:i:s", $fileModifiedTimestamp) . " GMT");
header('ETag: "' . md5($fileModifiedTimestamp . $fileName) . '"');
header('Cache-Control: public');
# Now check if file content needs to be send
if ($browserModifiedTimestamp !== null && $fileModifiedTimestamp <= $browserModifiedTimestamp) {
http_response_code(304);
return true;
}
return false;
}
