BUG/MEDIUM: cache: Fix hash collision in `accept-encoding` handling for `Vary`
This patch fixes GitHub Issue #988. Commit ce9e7b25217c46db1ac636b2c885a05bf91ae57e
was not sufficient, because it fell back to a hash comparison if the bitmap
of known encodings was not acceptable instead of directly returning the the
cached response is not compatible.
This patch also extends the reg-test to test the hash collision that was
mentioned in #988.
Vary handling is 2.4, no backport needed.
diff --git a/reg-tests/cache/vary.vtc b/reg-tests/cache/vary.vtc
index a840799..be79b6a 100644
--- a/reg-tests/cache/vary.vtc
+++ b/reg-tests/cache/vary.vtc
@@ -5,7 +5,8 @@
feature ignore_unknown_macro
server s1 {
- # Response varying on "accept-encoding"
+ # Response varying on "accept-encoding" with
+ # an unacceptable content-encoding
rxreq
expect req.url == "/accept-encoding"
txresp -hdr "Content-Encoding: gzip" \
@@ -16,6 +17,15 @@
# Response varying on "accept-encoding"
rxreq
expect req.url == "/accept-encoding"
+ txresp -hdr "Content-Encoding: gzip" \
+ -hdr "Vary: accept-encoding" \
+ -hdr "Cache-Control: max-age=5" \
+ -bodylen 45
+
+ # Response varying on "accept-encoding" with
+ # no content-encoding
+ rxreq
+ expect req.url == "/accept-encoding"
txresp -hdr "Content-Type: text/plain" \
-hdr "Vary: accept-encoding" \
-hdr "Cache-Control: max-age=5" \
@@ -57,7 +67,7 @@
expect req.url == "/referer-accept-encoding"
txresp -hdr "Vary: referer,accept-encoding" \
-hdr "Cache-Control: max-age=5" \
- -hdr "Content-Encoding: gzip" \
+ -hdr "Content-Encoding: br" \
-bodylen 54
rxreq
@@ -72,14 +82,14 @@
expect req.url == "/multiple_headers"
txresp -hdr "Vary: accept-encoding" \
-hdr "Cache-Control: max-age=5" \
- -hdr "Content-Encoding: gzip" \
+ -hdr "Content-Encoding: br" \
-bodylen 155
rxreq
expect req.url == "/multiple_headers"
txresp -hdr "Vary: accept-encoding" \
-hdr "Cache-Control: max-age=5" \
- -hdr "Content-Encoding: gzip" \
+ -hdr "Content-Encoding: br" \
-bodylen 166
@@ -163,6 +173,16 @@
expect resp.http.content-encoding == "gzip"
expect resp.bodylen == 45
+ # The response for the first request had an unacceptable `content-encoding`
+ # which might happen if that's the only thing the server supports, but
+ # we must not cache that and instead defer to the server.
+ txreq -url "/accept-encoding" -hdr "Accept-Encoding: first_value"
+ rxresp
+ expect resp.status == 200
+ expect resp.http.content-encoding == "gzip"
+ expect resp.bodylen == 45
+ expect resp.http.X-Cache-Hit == 0
+
txreq -url "/accept-encoding" -hdr "Accept-Encoding: second_value"
rxresp
expect resp.status == 200
@@ -170,11 +190,15 @@
expect resp.http.content-type == "text/plain"
expect resp.http.X-Cache-Hit == 0
+ # This request matches the cache entry for the request above, despite
+ # matching the `accept-encoding` of the first request because the
+ # request above only has the `identity` encoding which is implicitly
+ # added, unless explicitely forbidden.
txreq -url "/accept-encoding" -hdr "Accept-Encoding: first_value"
rxresp
expect resp.status == 200
- expect resp.bodylen == 45
- expect resp.http.content-encoding == "gzip"
+ expect resp.bodylen == 48
+ expect resp.http.content-type == "text/plain"
expect resp.http.X-Cache-Hit == 1
txreq -url "/accept-encoding" -hdr "Accept-Encoding: second_value"
@@ -227,7 +251,7 @@
# Mixed Vary (Accept-Encoding + Referer)
txreq -url "/referer-accept-encoding" \
- -hdr "Accept-Encoding: first_value,second_value" \
+ -hdr "Accept-Encoding: br, gzip" \
-hdr "Referer: referer"
rxresp
expect resp.status == 200
@@ -235,7 +259,7 @@
expect resp.http.X-Cache-Hit == 0
txreq -url "/referer-accept-encoding" \
- -hdr "Accept-Encoding: first_value" \
+ -hdr "Accept-Encoding: br" \
-hdr "Referer: other-referer"
rxresp
expect resp.status == 200
@@ -243,7 +267,7 @@
expect resp.http.X-Cache-Hit == 0
txreq -url "/referer-accept-encoding" \
- -hdr "Accept-Encoding: second_value" \
+ -hdr "Accept-Encoding: gzip" \
-hdr "Referer: other-referer"
rxresp
expect resp.status == 200
@@ -252,14 +276,14 @@
txreq -url "/referer-accept-encoding" \
-hdr "Referer: referer" \
- -hdr "Accept-Encoding: second_value,first_value"
+ -hdr "Accept-Encoding: gzip, br"
rxresp
expect resp.status == 200
expect resp.bodylen == 51
expect resp.http.X-Cache-Hit == 1
txreq -url "/referer-accept-encoding" \
- -hdr "Accept-Encoding: first_value" \
+ -hdr "Accept-Encoding: br" \
-hdr "Referer: other-referer"
rxresp
expect resp.status == 200
@@ -267,7 +291,7 @@
expect resp.http.X-Cache-Hit == 1
txreq -url "/referer-accept-encoding" \
- -hdr "Accept-Encoding: second_value" \
+ -hdr "Accept-Encoding: gzip" \
-hdr "Referer: other-referer"
rxresp
expect resp.status == 200
@@ -277,16 +301,16 @@
# Multiple Accept-encoding headers
txreq -url "/multiple_headers" \
- -hdr "Accept-Encoding: first_encoding" \
- -hdr "Accept-Encoding: second_encoding,third_encoding"
+ -hdr "Accept-Encoding: gzip" \
+ -hdr "Accept-Encoding: br, deflate"
rxresp
expect resp.status == 200
expect resp.bodylen == 155
expect resp.http.X-Cache-Hit == 0
txreq -url "/multiple_headers" \
- -hdr "Accept-Encoding: third_encoding" \
- -hdr "Accept-Encoding: second_encoding,first_encoding"
+ -hdr "Accept-Encoding: deflate" \
+ -hdr "Accept-Encoding: br,gzip"
rxresp
expect resp.status == 200
expect resp.bodylen == 155