Re: Cookie inspection

[Omar Kilani]

On 5/29/07, Poul-Henning Kamp [EMAIL PROTECTED] wrote:
 In message [EMAIL PROTECTED], Omar
  Kilani writes:

 Doing something like req.http.Cookie.LANGUAGE *could* theoretically do
 the right thing (and use http_GetHdrField, although some browsers can
 send multiple values for the same cookie name... :) and *looks* right,
 but obviously has a very different meaning in VCL where it compiles
 to:

 The Planned syntax is:
 req.http.Cookie[language]

 and just as for http headers, the headers will be read sequentially
 and the last found value is used.

That makes a lot more sense. :)

Out of curiosity, are things like this documented on Trac or somewhere else?

I probably missed it searching the tickets - has this work been started?

 http://treehou.se/~omar/cookie-inspection-1.patch

 Not bad :-)

Hehe - I really just meant to illustrate what I was getting at with
the patch. ;)

It took longer to write the email than to code up the patch, which I
think says a lot about the hackability of the code and how easy it is
to understand.

 The other thing I'd like to be able to do is have some sort of 'first
 match over an array of header values' VCL construct, so you could vary
 the hash by whatever languages in Accept-Language your site supports

 Does your backend include a proper Vary: header when it selects on
 language ?

Yes, but I'm not sure how Vary on Accept-Language is supposed to work
- does it just add the entire value to the hash key or?

Wouldn't the hit rate be low on the cached content if this was the case?

For example, I'd serve en-US to all these browsers (whose language
settings I haven't changed):

Opera (which sends the following Accept-Language value):

en,ja;q=0.9,fr;q=0.8,de;q=0.7,es;q=0.6,it;q=0.5,nl;q=0.4,sv;q=0.3,nb;q=0.2,da;q=0.1,fi;q=0.1,pt;q=0.1,lv;q=0.1,zh-CN;q=0.1,zh-TW;q=0.1,ko;q=0.1,en;q=0.1

Safari:

en

Camino:

en,ja;q=0.9,fr;q=0.9,de;q=0.8,es;q=0.8,it;q=0.7,nl;q=0.6,sv;q=0.6,nb;q=0.5,da;q=0.4,fi;q=0.4,pt;q=0.3,lv;q=0.3,zh-Hans;q=0.2,zh-Hant;q=0.1,ko;q=0.1

But would they all be cached independently and served different
versions of the same document?

Thanks.

Regards,
Omar
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Cookie inspection

[Omar Kilani]

Hi there,

I have a web application which supports a bunch of interface/website
languages via Accept-Language headers and/or a user-overridden cookie
value.

I'd like to modify req.hash in vcl_hash to take into account the value
of this particular cookie (similar to what Denis does with
Accept-Encoding here:
http://projects.linpro.no/pipermail/varnish-misc/2007-May/000407.html
-- neat! :)

From looking through the varnish-cache code, I don't think this type
of operation is supported, and I'm not sure what the best way to
represent this in VCL is.

Including the entire req.http.Cookie in the hash key is suboptimal as
there are a bunch of other cookies set (session cookies, etc)
depending on other variables.

Doing something like req.http.Cookie.LANGUAGE *could* theoretically do
the right thing (and use http_GetHdrField, although some browsers can
send multiple values for the same cookie name... :) and *looks* right,
but obviously has a very different meaning in VCL where it compiles
to:

VRT_GetHdr(sp, 1, \020Cookie.LANGUAGE:)

I've created a small patch:

http://treehou.se/~omar/cookie-inspection-1.patch

Which implements VRT_GetHdrField and cookie inspection.

This should be a lot more general, but is this something that varnish
could potentially support?

The other thing I'd like to be able to do is have some sort of 'first
match over an array of header values' VCL construct, so you could vary
the hash by whatever languages in Accept-Language your site supports
-- but the cookie thing would be workable too.

Thanks!

Regards,
Omar
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