<?xml version="1.0" encoding="ISO-8859-1"?>
<slide fontsize="6em">
	<title>Squid</title>

	<list effect="slide" fontsize="5em">
		<bullet>transparent caching</bullet>
		<bullet>caches HTTP and FTP</bullet>
	</list>
	<blurb> </blurb>

	<blurb fontsize="3em">Some effort to use with PHP:</blurb>
	<example fontsize="1.7em"><![CDATA[<?php
$tsstring = gmdate("D, d M Y H:i:s ", $timestamp)."GMT";

if ($_SERVER["HTTP_IF_MODIFIED_SINCE"] == $tsstring) {
    /* The UA has the exact same page we have. */
    header("HTTP/1.1 304 Not Modified");
    exit();
} else {
    header("Last-Modified: ".$tsstring);
}
? >]]></example>
</slide>
