>From d1701c99b24e2455c44566c29fe7d5a01140df64 Mon Sep 17 00:00:00 2001
From: Nils Goroll <[email protected]>
Date: Thu, 18 Dec 2014 13:18:55 +0100
Subject: [PATCH] expose response 304 status to VCL
---
bin/varnishd/cache/cache_fetch.c | 3 ++-
bin/varnishd/cache/cache_http.c | 4 ++--
bin/varnishtest/tests/b00039.vtc | 7 +++++++
doc/sphinx/users-guide/vcl-built-in-subs.rst | 16 +++++++++++++++-
4 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/bin/varnishd/cache/cache_fetch.c b/bin/varnishd/cache/cache_fetch.c
index 93d6ea7..c1d563b 100644
--- a/bin/varnishd/cache/cache_fetch.c
+++ b/bin/varnishd/cache/cache_fetch.c
@@ -404,7 +404,6 @@ vbf_stp_startfetch(struct worker *wrk, struct busyobj *bo)
}
http_Unset(bo->beresp, H_Content_Length);
HTTP_Merge(bo->wrk, bo->ims_oc, bo->beresp);
- assert(http_IsStatus(bo->beresp, 200));
do_ims = 1;
} else
do_ims = 0;
@@ -439,6 +438,8 @@ vbf_stp_startfetch(struct worker *wrk, struct busyobj *bo)
assert(bo->state == BOS_REQ_DONE);
+ if (do_ims && ! http_IsStatus(bo->beresp, 200))
+ http_SetStatus(bo->beresp, 200);
if (bo->do_esi)
bo->do_stream = 0;
if (bo->do_pass || bo->uncacheable)
diff --git a/bin/varnishd/cache/cache_http.c b/bin/varnishd/cache/cache_http.c
index e655fa0..fbfddf6 100644
--- a/bin/varnishd/cache/cache_http.c
+++ b/bin/varnishd/cache/cache_http.c
@@ -959,13 +959,13 @@ HTTP_Merge(struct worker *wrk, struct objcore *oc, struct http *to)
ptr = ObjGetattr(wrk, oc, OA_HEADERS, NULL);
AN(ptr);
- to->status = vbe16dec(ptr + 2);
+ /* Skip nhd and status */
ptr += 4;
+ /* skip HTTP_HDR_PROTO, HTTP_HDR_STATUS, HTTP_HDR_REASON */
for (u = 0; u < HTTP_HDR_FIRST; u++) {
if (u == HTTP_HDR_METHOD || u == HTTP_HDR_URL)
continue;
- http_SetH(to, u, ptr);
ptr = strchr(ptr, '\0') + 1;
}
while (*ptr != '\0') {
diff --git a/bin/varnishtest/tests/b00039.vtc b/bin/varnishtest/tests/b00039.vtc
index cf1e9dc..5417391 100644
--- a/bin/varnishtest/tests/b00039.vtc
+++ b/bin/varnishtest/tests/b00039.vtc
@@ -10,6 +10,10 @@ server s1 {
varnish v1 -vcl+backend {
sub vcl_backend_response {
+ if (bereq.http.If-Modified-Since &&
+ beresp.status != 304) {
+ return(abandon);
+ }
set beresp.ttl = 2s;
set beresp.grace = 20s;
set beresp.keep = 1m;
@@ -20,6 +24,7 @@ client c1 {
txreq
rxresp
expect resp.status == 200
+ expect resp.http.Last-Modified == "Wed, 11 Sep 2013 13:36:55 GMT"
expect resp.body == "Geoff Rules"
} -run
@@ -29,6 +34,7 @@ client c1 {
txreq
rxresp
expect resp.status == 200
+ expect resp.http.Last-Modified == "Wed, 11 Sep 2013 13:36:55 GMT"
expect resp.body == "Geoff Rules"
} -run
@@ -36,5 +42,6 @@ client c1 {
txreq
rxresp
expect resp.status == 200
+ expect resp.http.Last-Modified == "Wed, 11 Sep 2013 13:36:55 GMT"
expect resp.body == "Geoff Rules"
} -run
diff --git a/doc/sphinx/users-guide/vcl-built-in-subs.rst b/doc/sphinx/users-guide/vcl-built-in-subs.rst
index cd78355..864a99f 100644
--- a/doc/sphinx/users-guide/vcl-built-in-subs.rst
+++ b/doc/sphinx/users-guide/vcl-built-in-subs.rst
@@ -277,11 +277,25 @@ vcl_backend_response
Called after the response headers have been successfully retrieved from
the backend.
+For a 304 response, varnish core code amends ``beresp`` before calling
+`vcl_backend_response`:
+
+* If the gzip status changed, ``Content-Encoding`` is unset and any
+ ``Etag`` is weakened
+
+* Any headers not present in the 304 response are copied from the
+ existing cache object. ``Content-Length`` is copied if present in
+ the existing cache object and discarded otherwise.
+
The `vcl_backend_response` subroutine may terminate with calling
``return()`` with one of the following keywords:
``deliver``
- For a 304 response, create an updated cache object.
+ For a 304 response, set the status to 200 and create an updated
+ cache object. Conditional requests will be handled on the client
+ side, so clients may still receive a 304 response based on their
+ requst headers.
+
Otherwise, fetch the object body from the backend and initiate
delivery to any waiting client requests, possibly in parallel
(streaming).
--
2.1.3
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