# HG changeset patch
# User Vadim Fedorenko <vadim.fedorenko@cdnnow.ru>
# Date 1649889268 -10800
# Thu Apr 14 01:34:28 2022 +0300
# Node ID ed7a2c031475bcb252952a467c184c94652b926a
# Parent a736a7a613ea6e182ff86fbadcb98bb0f8891c0b
Upstream: prioritise Cache-Control over Expires.

RFC7234 explicitly says that cache recipient MUST ignore Expires
header if response includes Cache-Control header with max-age or
s-maxage directives. Previously Cache-Control was ignored if it
was after Expires in reply headers.

At the same time this patch makes more stable behaviour of using
latest value of header Cache-Control even if previous value was 0.
Ticket #964 for more information.
---
src/http/ngx_http_upstream.c | 25 +++++++++++++++++++++++++
src/http/ngx_http_upstream.h | 15 +++++++++++++++
2 files changed, 40 insertions(+)

diff -r a736a7a613ea -r ed7a2c031475 src/http/ngx_http_upstream.c
--- a/src/http/ngx_http_upstream.c Tue Feb 08 17:35:27 2022 +0300
+++ b/src/http/ngx_http_upstream.c Thu Apr 14 01:34:28 2022 +0300
@@ -868,6 +868,7 @@
}

u->cacheable = 1;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_DEFAULT;

c = r->cache;

@@ -970,6 +971,7 @@
case NGX_HTTP_CACHE_SCARCE:

u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_SCARCE;

break;

@@ -992,6 +994,7 @@

if (ngx_http_upstream_cache_check_range(r, u) == NGX_DECLINED) {
u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_RANGE;
}

r->cached = 0;
@@ -3105,6 +3108,7 @@

case NGX_DECLINED:
u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_NO_CACHE;
break;

default: /* NGX_OK */
@@ -3165,6 +3169,7 @@

} else {
u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_INVALID;
}
}

@@ -4690,6 +4695,7 @@
#if (NGX_HTTP_CACHE)
if (!(u->conf->ignore_headers & NGX_HTTP_UPSTREAM_IGN_SET_COOKIE)) {
u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_COOKIE;
}
#endif

@@ -4747,6 +4753,7 @@
|| ngx_strlcasestrn(start, last, (u_char *) "private", 7 - 1) != NULL)
{
u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_NO_CACHE;
return NGX_OK;
}

@@ -4772,15 +4779,21 @@
}

u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_CACHECTRL0;
return NGX_OK;
}

if (n == 0) {
u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_CACHECTRL0;
return NGX_OK;
}

r->cache->valid_sec = ngx_time() + n;
+ u->cacheable_reason &= ~(NGX_HTTP_CACHEABLE_CACHECTRL0|NGX_HTTP_CACHEABLE_EXPIRES);
+ if (u->cacheable_reason == NGX_HTTP_CACHEABLE_DEFAULT) {
+ u->cacheable = 1;
+ }
}

p = ngx_strlcasestrn(start, last, (u_char *) "stale-while-revalidate=",
@@ -4800,9 +4813,13 @@
}

u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_CACHECTRL1;
return NGX_OK;
}

+ if (u->cacheable_reason == NGX_HTTP_CACHEABLE_DEFAULT) {
+ u->cacheable = 1;
+ }
r->cache->updating_sec = n;
r->cache->error_sec = n;
}
@@ -4823,10 +4840,15 @@
}

u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_CACHECTRL2;
return NGX_OK;
}

r->cache->error_sec = n;
+ u->cacheable_reason &= ~NGX_HTTP_CACHEABLE_EXPIRES;
+ if (u->cacheable_reason == NGX_HTTP_CACHEABLE_DEFAULT) {
+ u->cacheable = 1;
+ }
}
}
#endif
@@ -4864,6 +4886,7 @@

if (expires == NGX_ERROR || expires < ngx_time()) {
u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_EXPIRES;
return NGX_OK;
}

@@ -4907,6 +4930,7 @@
switch (n) {
case 0:
u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_XACCEL;
/* fall through */

case NGX_ERROR:
@@ -5067,6 +5091,7 @@
|| (h->value.len == 1 && h->value.data[0] == '*'))
{
u->cacheable = 0;
+ u->cacheable_reason |= NGX_HTTP_CACHEABLE_VARY;
}

r->cache->vary = h->value;
diff -r a736a7a613ea -r ed7a2c031475 src/http/ngx_http_upstream.h
--- a/src/http/ngx_http_upstream.h Tue Feb 08 17:35:27 2022 +0300
+++ b/src/http/ngx_http_upstream.h Thu Apr 14 01:34:28 2022 +0300
@@ -320,6 +320,20 @@
ngx_http_upstream_t *u);


+#define NGX_HTTP_CACHEABLE_DEFAULT 0x80000000
+#define NGX_HTTP_CACHEABLE_SCARCE 0x00000001
+#define NGX_HTTP_CACHEABLE_RANGE 0x00000002
+#define NGX_HTTP_CACHEABLE_INVALID 0x00000004
+#define NGX_HTTP_CACHEABLE_NO_CACHE 0x00000010
+#define NGX_HTTP_CACHEABLE_EXPIRES 0x00000020
+#define NGX_HTTP_CACHEABLE_COOKIE 0x00000040
+#define NGX_HTTP_CACHEABLE_CACHECTRL0 0x00000100
+#define NGX_HTTP_CACHEABLE_CACHECTRL1 0x00000200
+#define NGX_HTTP_CACHEABLE_CACHECTRL2 0x00000400
+#define NGX_HTTP_CACHEABLE_XACCEL 0x00001000
+#define NGX_HTTP_CACHEABLE_VARY 0x00002000
+
+
struct ngx_http_upstream_s {
ngx_http_upstream_handler_pt read_event_handler;
ngx_http_upstream_handler_pt write_event_handler;
@@ -384,6 +398,7 @@

ngx_http_cleanup_pt *cleanup;

+ ngx_uint_t cacheable_reason;
unsigned store:1;
unsigned cacheable:1;
unsigned accel:1;
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