Patrick Lucas created FLINK-5843:
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Summary: Website/docs missing Cache-Control HTTP header, can serve
stale data
Key: FLINK-5843
URL: https://issues.apache.org/jira/browse/FLINK-5843
Project: Flink
Issue Type: Bug
Components: Project Website
Reporter: Patrick Lucas
When Flink 1.2.0 was released, I found that the [Flink downloads
page|https://flink.apache.org/downloads.html] was out-of-date until I forced my
browser to refresh the page. Upon investigation, I found that the principle
pages of the website are served with only the following headers that relate to
caching: Date, Last-Modified, and ETag.
Since there is no Cache-Control header (or the older Expires or Pragma
headers), browsers are left to their own heuristics as to how long to cache
this content, which varies browser to browser. In some browsers, this heuristic
is 10% of the difference between Date and Last-Modified headers. I take this to
mean that, if the content were last modified 90 days ago, and I last accessed
it 5 days ago, my browser will serve a cached response for a further 3.5 days
(10% * (90 days - 5 days) = 8.5 days, 5 days have elapsed leaving 3.5 days).
I'm not sure who at the ASF we should talk to about this, but I recommend we
add the following header to any responses served from the Flink project website
or official documentation website\[1]:
{code}Cache-Control: max-age=0, must-revalidate{code}
(Note this will only make browser revalidate their caches; if the ETag of the
cached content matches what the server still has, the server will return 304
Not Modified and omit the actual content)
\[1] Both the website hosted at flink.apache.org and the documentation hosted
at ci.apache.org are affected.
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