浏览器不会缓存动态CSS - 响应返回200 OK而不是304 Not Modified
I have dynamic CSS file like this:
$Css = get_from($_u_6);
/* do stuff and other things here... */
$expires = 60*60*24;
header("Pragma: public");
header("Cache-Control: maxage=".$expires.", must-revalidate, public");
header('Expires: ' . gmdate('D, d M Y H:i:s', time()+$expires) . ' GMT');
header('Content-type: text/css');
echo $Css;
Headers are set correctly: http://i.imgur.com/MIH7j5U.png
But The server always responds with HTTP 200 OK (and the correct content), rather than with a HTTP 304 ( Not Modified).
How can I convince the browser and the server to cache these dynamic css files and to send 304 response?
我有这样的动态CSS文件： p>
$ Css = get_from（$ _ u_6）;
/ *在这里做东西和其他东西...... * /
$ expires = 60 * 60 * 24;
header（“Pragma：public”）;
header（“Cache-Control：maxage =”。$ expires。“，must-revalidate，public”）;
header（'Expires：'。gmdate（'D，d MYH） ：i：s'，time（）+ $ expires）。'GMT'）;
header（'Content-type：text / css'）;
echo $ Css;
code> pre>
标题设置正确：
http://i.imgur.com /MIH7j5U.png p>
但服务器始终以 HTTP 200 OK strong>（和正确的内容）响应，而不是使用 HTTP响应 304（未修改） strong>。 p>
如何说服浏览器和服务器缓存这些动态css文件并发送304响应？ p>
DIV>
The Expires: header tells the browser or cache server how long it can keep reusing the same resource without reloading it from the origin server.
If you want the browser to make a conditional request (eg. using If-Modified-Since: or If-None-Match:), you need to send a Last-Modified: and/or ETag: header, and you need to write code to test for these headers and produce the appropriate response (304 or 200).