MEDIUM: cache: Change caching conditions
Do not cache responses that do not have an explicit expiration time
(s-maxage or max-age Cache-Control directives or Expires header) or a
validator (ETag or Last-Modified headers) anymore, as suggested in
RFC 7234#3.
The TX_FLAG_IGNORE flag is used instead of the TX_FLAG_CACHEABLE so as
not to change the behavior of the checkcache option.
diff --git a/reg-tests/cache/caching_rules.vtc b/reg-tests/cache/caching_rules.vtc
new file mode 100644
index 0000000..1abd924
--- /dev/null
+++ b/reg-tests/cache/caching_rules.vtc
@@ -0,0 +1,150 @@
+varnishtest "Caching rules test"
+# A respnse will not be cached unless it has an explicit age (Cache-Control max-age of s-maxage, Expires, Last-Modified headers, or ETag)
+
+#REQUIRE_VERSION=1.9
+
+feature ignore_unknown_macro
+
+server s1 {
+ rxreq
+ expect req.url == "/max-age"
+ txresp -hdr "Cache-Control: max-age=5" \
+ -bodylen 150
+
+ rxreq
+ expect req.url == "/s-maxage"
+ txresp -hdr "Cache-Control: s-maxage=5" \
+ -bodylen 160
+
+ rxreq
+ expect req.url == "/last-modified"
+ txresp -hdr "Last-Modified: Thu, 22 Oct 2020 16:51:12 GMT" \
+ -bodylen 180
+
+ rxreq
+ expect req.url == "/etag"
+ txresp -hdr "ETag: \"etag\"" \
+ -bodylen 190
+
+ rxreq
+ expect req.url == "/uncacheable"
+ txresp \
+ -bodylen 200
+
+ rxreq
+ expect req.url == "/uncacheable"
+ txresp \
+ -bodylen 210
+} -start
+
+server s2 {
+ rxreq
+ expect req.url == "/expires"
+ # Expires header is filled directly by the expires_be backend"
+ txresp \
+ -bodylen 170
+} -start
+
+haproxy h1 -conf {
+ defaults
+ mode http
+ ${no-htx} option http-use-htx
+ timeout connect 1s
+ timeout client 1s
+ timeout server 1s
+
+ frontend fe
+ bind "fd@${fe}"
+ use_backend expires_be if { path_beg /expires }
+ default_backend test
+
+ backend expires_be
+ http-request cache-use my_cache
+ server www ${s2_addr}:${s2_port}
+ http-response set-header X-Cache-Hit %[res.cache_hit]
+ # Expires value set in the future (current_time+5s)
+ http-response set-header Expires %[date(5),http_date]
+ http-response cache-store my_cache
+
+ backend test
+ http-request cache-use my_cache
+ server www ${s1_addr}:${s1_port}
+ http-response cache-store my_cache
+ http-response set-header X-Cache-Hit %[res.cache_hit]
+
+ cache my_cache
+ total-max-size 3
+ max-age 20
+ max-object-size 3072
+} -start
+
+
+client c1 -connect ${h1_fe_sock} {
+ txreq -url "/max-age"
+ rxresp
+ expect resp.status == 200
+ expect resp.bodylen == 150
+
+ txreq -url "/max-age"
+ rxresp
+ expect resp.status == 200
+ expect resp.bodylen == 150
+ expect resp.http.X-Cache-Hit == 1
+
+ txreq -url "/s-maxage"
+ rxresp
+ expect resp.status == 200
+ expect resp.bodylen == 160
+
+ txreq -url "/s-maxage"
+ rxresp
+ expect resp.status == 200
+ expect resp.bodylen == 160
+ expect resp.http.X-Cache-Hit == 1
+
+ txreq -url "/expires"
+ rxresp
+ expect resp.status == 200
+ expect resp.bodylen == 170
+
+ txreq -url "/expires"
+ rxresp
+ expect resp.status == 200
+ expect resp.bodylen == 170
+ expect resp.http.X-Cache-Hit == 1
+
+ txreq -url "/last-modified"
+ rxresp
+ expect resp.status == 200
+ expect resp.bodylen == 180
+
+ txreq -url "/last-modified"
+ rxresp
+ expect resp.status == 200
+ expect resp.bodylen == 180
+ expect resp.http.X-Cache-Hit == 1
+
+ txreq -url "/etag"
+ rxresp
+ expect resp.status == 200
+ expect resp.bodylen == 190
+
+ txreq -url "/etag"
+ rxresp
+ expect resp.status == 200
+ expect resp.bodylen == 190
+ expect resp.http.X-Cache-Hit == 1
+
+ # The next response should not be cached
+ txreq -url "/uncacheable"
+ rxresp
+ expect resp.status == 200
+ expect resp.bodylen == 200
+
+ txreq -url "/uncacheable"
+ rxresp
+ expect resp.status == 200
+ expect resp.bodylen == 210
+ expect resp.http.X-Cache-Hit == 0
+
+} -run