Re: [squid-users] Caching dynamic content, trading between HTTP versions

From: Andrea Aime <>
Date: Tue, 30 Apr 2013 12:45:58 +0200

Thanks for the prompt reply. Comments inline.

On Tue, Apr 30, 2013 at 12:21 PM, Amos Jeffries <> wrote:
>> So basically, we need the cache to talk HTTP 1.1 with the webapp.
> Both If-Modified-Since and If-None-Modified are optional features. There is
> no requirement in HTTP for any of the client, gateway or server to use
> either of them.

Yes, that was my understanding as well. However, I thought major browsers
support them, and assumed (wrongly it seems) that Squid would also support them.
By your mail it seems Squid does not support validation towards the dynamic
webapp via If-None-Modified.
Out of curiosity, does it support If-Modified-Since instead?

>> So far so good. Now enter a second level of caching, a CDN made with
>> cloudfront,
>> and here is the gotcha: cloudfront only supports HTTP 1.0 requests towards
>> the
>> origin, which in this case would be Squid.
> That is unfortunate. A missing feature in CloudFront. Even more
> unfortunately it coincides with Squid missing the same feature ...

Unfortunately CloudFront is not open source, so nothing I can do about it:
(besides eventually looking into another CDN solution)

>> Any other suggestion about how this could be handled?
> Adding the If-None-Modified feature to either CloudFront or Squid is
> probably a good solution. I believe have a project
> underway to add it to Squid. You may want to contact Alex there about
> getting access or sponsoring further progress.

Thanks for letting me know.
However, would it do me any good if CloudFront does not support


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Received on Tue Apr 30 2013 - 10:46:14 MDT

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