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Document the order of the X-Cache header #6328

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mlibbey merged 1 commit into from
Feb 4, 2020
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Document the order of the X-Cache header #6328

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6 changes: 5 additions & 1 deletion doc/admin-guide/plugins/xdebug.en.rst
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Expand Up @@ -78,7 +78,7 @@ X-Cache-Key
key is being used.

X-Cache
The ``X-Cache`` header contains the results of any cache lookup.
The ``X-Cache`` header contains the results of any cache lookups.

========== ===========
Value Description
Expand All @@ -90,6 +90,10 @@ X-Cache
skipped The cache lookup was skipped.
========== ===========

If a request goes through multiple proxies, each one prepends its X-Cache header content
at the beginning of the existing X-Cache header. As a result, the order is reversed from
the Via: header.
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@zwoop zwoop Jan 16, 2020

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Nice. I wonder, since the behavior of the Via header is pretty darn well known (and defined), should we not adhere to this for X-Cache too ? What does Akamai do ?

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@mlibbey mlibbey Jan 16, 2020

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At least for us, Akamai does not expose multiple layers for their equivalent, X-cache and X-cache-remote -- both are single layer only.


X-Cache-Generation
The cache generation ID for this transaction, as specified by the
:ts:cv:`proxy.config.http.cache.generation` configuration variable.
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