When Last-Modified is unknown, you can still use ETags, but you need a short
string that is unique for that content. In the worst case, you have to generate
all the content first, then instantiate HTTP_ConditionalGet, setting
the array key contentHash to the output of a hash function of the
content. Since we have the full content, we might as well also use
setContentLength(strlen($content)) in the case where we need to
send it.
This script emulates a document that changes every ' .$every. ' seconds.
This is version: ' . date('r', $lastModified) . '
';
require '_include.php';
$content = get_content(array(
'title' => $title
,'explain' => $explain
));
$cg = new HTTP_ConditionalGet(array(
'contentHash' => substr(md5($content), 7)
));
if ($cg->cacheIsValid) {
$cg->sendHeaders();
// we're done
exit();
}
$cg->setContentLength(strlen($content));
$cg->sendHeaders();
send_slowly($content);