varnish not generating 304 in case multiple etags are used.

[Harm Verhagen]

Hi,

I'm having a problem with the handling of http responses that contain
multiple etag headers.  I think varnish does not handle this case as
effecient as it can. (And therefor I suspect a bug in varnish).
What do you think?


steps to reproduce
==============
See request/response below. Force a reload of a cached item in browser:
Cache-Control: max-age=0

result
====
HTTP 200 is returned, varnish serves file content, varnish does NOT contact
backend.

expected result
============
HTTP 304 is returned, varnish does not server file content, varnish does NOT
contact backend.

NOTE
=====
This does work correct, in case  the reply contains a SINGLE  etag header.
-> all works as expected, I get a nice 304 instead of a 200.
As soon as the reply contains TWO etag headers, it seems varnish never
returns a 304. Which I think is incorrect. No ?

Note; This is not related to the vlc, as single etag headers are working
fine.  (I'm doing NOTHING  with headers, etag or others in my vlc).

request (anonimised)
=======

GET /dam/asset/download/uuid/121a8df4-4fe8-11e0-bd65-56167b3dc56d/variant/103/
HTTP/1.1
Host: X.X.X
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:2.0)
Gecko/20100101 Firefox/4.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: nl,en-us;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive
Cookie: __utma=1.1741069999.1296235686.1303504321.1303507491.8;
<snipped rest of cookie>
If-Modified-Since: Fri, 22 Apr 2011 13:00:00 GMT
If-None-Match: "d41d8cd98f00b204e9800998ecf8427e", "4a00e1-3ddf-4a1816f7a9400"
Cache-Control: max-age=0


reply

HTTP/1.1 200 OK
Server: Apache/2.2.14 (Ubuntu)
Content-Disposition: inline; filename="Seminar Speakers.jpg"
Expires: Sat, 23 Apr 2011 13:00:00 GMT
Etag: "d41d8cd98f00b204e9800998ecf8427e", "4a00e1-3ddf-4a1816f7a9400"
Cache-Control: max-age=86400
P3P: CP="IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT"
Last-Modified: Fri, 22 Apr 2011 13:00:00 GMT
Content-Type: image/jpeg;charset=utf-8
Content-Length: 15839
Date: Sat, 23 Apr 2011 12:07:39 GMT
X-Varnish: 2113947582 2113947501
Age: 58
Via: 1.1 varnish
Connection: keep-alive




version
======
varnish 2.1.5



Log transcript of a single request+response (varnishlog)
=================================
   11 SessionOpen  c X.X.X.220 50540 :80
   11 ReqStart     c X.X.X.220 50540 2113947582
   11 RxRequest    c GET
   11 RxURL        c
/dam/asset/download/uuid/121a8df4-4fe8-11e0-bd65-56167b3dc56d/variant/103/
   11 RxProtocol   c HTTP/1.1
   11 RxHeader     c Host: X.X.X
   11 RxHeader     c User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X
10.6; rv:2.0) Gecko/20100101 Firefox/4.0
   11 RxHeader     c Accept:
text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
   11 RxHeader     c Accept-Language: nl,en-us;q=0.7,en;q=0.3
   11 RxHeader     c Accept-Encoding: gzip, deflate
   11 RxHeader     c Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
   11 RxHeader     c Keep-Alive: 115
   11 RxHeader     c Connection: keep-alive
   11 RxHeader     c Cookie:
__utma=1.1741069999.1296235686.1303504321.1303507491.8;
__utmz=1.1303507491.8.8.utmcsr=senzio.com|utmccn=(referral)|utmcmd=referral|utmcct=/;
__utma=142895841.963436971.1296236932.1302872710.1303499754.14;
__utmz=142895841.1296236932.1.1.utmcsr=(d
   11 RxHeader     c If-Modified-Since: Fri, 22 Apr 2011 13:00:00 GMT
   11 RxHeader     c If-None-Match: "d41d8cd98f00b204e9800998ecf8427e",
"4a00e1-3ddf-4a1816f7a9400"
   11 RxHeader     c Cache-Control: max-age=0
   11 VCL_call     c recv
   11 VCL_return   c lookup
   11 VCL_call     c hash
   11 VCL_return   c hash
   11 Hit          c 2113947501
   11 VCL_call     c hit
   11 LostHeader   c X-Cache:
   11 VCL_return   c deliver
   11 VCL_call     c deliver
   11 VCL_return   c deliver
   11 TxProtocol   c HTTP/1.1
   11 TxStatus     c 200
   11 TxResponse   c OK
   11 TxHeader     c Server: Apache/2.2.14 (Ubuntu)
   11 TxHeader     c Content-Disposition: inline; filename="Seminar
Speakers.jpg"
   11 TxHeader     c Expires: Sat, 23 Apr 2011 13:00:00 GMT
   11 TxHeader     c ETag: "d41d8cd98f00b204e9800998ecf8427e"
   11 TxHeader     c Cache-Control: max-age=86400
   11 TxHeader     c P3P: CP="IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi
CONi HIS OUR IND CNT"
   11 TxHeader     c Last-Modified: Fri, 22 Apr 2011 13:00:00 GMT
   11 TxHeader     c ETag: "4a00e1-3ddf-4a1816f7a9400"
   11 TxHeader     c Content-Type: image/jpeg;charset=utf-8
   11 TxHeader     c Content-Length: 15839
   11 TxHeader     c Date: Sat, 23 Apr 2011 12:07:39 GMT
   11 TxHeader     c X-Varnish: 2113947582 2113947501
   11 TxHeader     c Age: 58
   11 TxHeader     c Via: 1.1 varnish
   11 TxHeader     c Connection: keep-alive
   11 Length       c 15839
   11 ReqEnd       c 2113947582 1303560459.219877005 1303560459.317925930
0.000497818 0.000181675 0.097867250
   11 Debug        c "herding"
    0 ExpKill      - 2113947483 -30
    0 CLI          - Rd ping
    0 CLI          - Wr 200 19 PONG 1303560459 1.0


Regards,
Harm Verhagen
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