必重新验证这一请求错头？ [英] Must-revalidate headers of this request wrong?

问题描述

我注意到，铬缓存的视频文件。我在服务器上另一个替换了它和Chrome保持服务从缓存中旧的（使用JW Flash播放器5）

I noticed that chrome cached a video file. I replaced it with another one on the server and chrome kept serving the old one from cache (using JW flash player 5)

请求看起来像这样的标题：

The headers of the request look like this:

joe@joe-desktop:~$ wget -O - -S --spider http://www.2xfun.de/files_geheimhihi14/20759.mp4
Spider mode enabled. Check if remote file exists.
--2011-05-15 22:40:56--  http://www.2xfun.de/files_geheimhihi14/20759.mp4
Resolving www.2xfun.de... 213.239.214.112
Connecting to www.2xfun.de|213.239.214.112|:80... connected.
HTTP request sent, awaiting response... 
  HTTP/1.1 200 OK
  Date: Sun, 15 May 2011 20:40:56 GMT
  Server: Apache
  Last-Modified: Sun, 15 May 2011 20:37:59 GMT
  ETag: "89b38-3bb227-4a35683b477c0"
  Accept-Ranges: bytes
  Content-Length: 3912231
  Cache-Control: max-age=29030400, public, must-revalidate
  Expires: Sun, 15 Apr 2012 20:40:56 GMT
  Connection: close
  Content-Type: video/mp4
Length: 3912231 (3.7M) [video/mp4]
Remote file exists.

我使用mod_headers中，并指定mod_expires在Apache2的是这样的：

I am using mod_headers and mod_expires in apache2 like this:

<FilesMatch "\.(flv|ico|pdf|avi|mov|ppt|doc|mp3|wmv|wav|mp4)$">
ExpiresDefault A29030400
Header append Cache-Control "public, must-revalidate"
</FilesMatch>

我有没有拼写错误重新验证什么？

Did I spell revalidate wrong or something?

编辑：

为了让用例明确：我要的文件被缓存，因为他们是相当大的，我想节省带宽。但在另一方面，我要的文件被重新验证。因此，客户端执行HEAD请求，并检查内容是否已经改变（多数民众赞成在ETAG是什么），只有重新获取，如果必要的。

To make the use case clear: I want the files to be cached, because they are rather big and I want to save bandwidth. But on the other hand I want the files to be re-validated. So the client does a HEAD request and checks whether the content has changed (thats what the etag is for), and only re-fetches if necessary.

推荐答案

您的问题是必须 - 重新验证只踢一次缓存条目已经不再新鲜，但你标记的响应作为缓存为29000000秒。 缓存控制：最大年龄= 0，必重新验证可能更接近你想要什么，如果你想允许缓存，但需要在每次使用重新验证。

Your problem is that must-revalidate only kicks in once a cache entry is no longer fresh, but you've marked the response as cacheable for 29 million seconds. 'Cache-Control: max-age=0, must-revalidate' may be closer to what you want, if you want to allow caching but require revalidation on each use.

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