/**
* Answer true if the content has modified since the cache was last
* updated, false otherwise.
*
* Based on info from:
* Simon Willison - http://simonwillison.net/2003/Apr/23/conditionalGet/
* http://fishbowl.pastiche.org/archives/001132.html
*
*
* @param object DateAndTime $timestamp
* @param string $eTag
* @return boolean
* @access private
* @since 5/13/08
*/
private function changed(DateAndTime $timestamp, $eTag)
{
if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
$clientTimestamp = DateAndTime::fromString(stripslashes($_SERVER['HTTP_IF_MODIFIED_SINCE']));
}
if (isset($_SERVER['HTTP_IF_NONE_MATCH'])) {
$clientETag = trim($_SERVER['HTTP_IF_NONE_MATCH']);
$eTag = trim($eTag);
}
// Check the HTTP 1.1 ETag/If None Match parts first.
if (isset($clientETag) && $clientETag == $eTag) {
return false;
}
// Check the HTTP 1.0 Modification date
if (isset($clientTimestamp) && $timestamp->isLessThanOrEqual($clientTimestamp)) {
return false;
}
return true;
}