Re: [Tails-dev] Server-side caching settings of IDF

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Author: intrigeri
Date:  
To: Giorgio Maone
CC: The Tails public development discussion list
Subject: Re: [Tails-dev] Server-side caching settings of IDF
Hi Giorgio,

Giorgio Maone wrote (25 Apr 2016 17:31:01 GMT) :
> On 25/04/2016 18:18, intrigeri wrote:
>>> Right. The server now sets both Cache-Control and Expires headers to
>>> "last access time + 2 hours", for IDFs.
>>> How can I verify, from the client side, that DAVE honors these?
>>> Using some Firefox developer tool, perhaps?
>>
> Yep, ctrl+k, "Net" tab.


I've navigated through a few pages of our Installation Assistant, and
it seems to me that DAVE fetches the body every time.

The response header always includes:

Cache-Control: max-age=7200, must-revalidate
Last-Modified: Fri, 20 May 2016 21:11:45 GMT

... and:

Date: Tue, 24 May 2016 14:40:00 GMT
Expires: Tue, 24 May 2016 16:40:00 GMT

+ a few seconds for both, corresponding to when I've loaded the
new page.

FWIW, the request headers always include:

Pragma: no-cache
Cache-Control: no-cache

If I use "Edit and resend" to remove these two headers twice, the next
request still downloads the body and presumably caches it, since the
next request takes the body from the cache.

It seems to me that the whole point of enabling server-side caching
was to enable DAVE to avoid fetching latest.yml for every visited
page, but apparently that's not enough. So perhaps DAVE should not
send these two headers? Or did I miss something?

Cheers,
--
intrigeri