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changeset 8041:0784ab86ad08

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Upstream: fixed X-Accel-Expires/Cache-Control/Expires handling. Previously, if caching was disabled due to Expires in the past, nginx failed to cache the response even if it was cacheable as per subsequently parsed Cache-Control header (ticket #964). Similarly, if caching was disabled due to Expires in the past, "Cache-Control: no-cache" or "Cache-Control: max-age=0", caching was not used if it was cacheable as per subsequently parsed X-Accel-Expires header. Fix is to avoid disabling caching immediately after parsing Expires in the past or Cache-Control, but rather set flags which are later checked by ngx_http_upstream_process_headers() (and cleared by "Cache-Control: max-age" and X-Accel-Expires). Additionally, now X-Accel-Expires does not prevent parsing of cache control extensions, notably stale-while-revalidate and stale-if-error. This ensures that order of the X-Accel-Expires and Cache-Control headers is not important. Prodded by Vadim Fedorenko and Yugo Horie.
author Maxim Dounin <mdounin@mdounin.ru>
date Tue, 07 Jun 2022 00:07:12 +0300
parents e0cfab501dd1
children c7e25324be11
files src/http/ngx_http_upstream.c src/http/ngx_http_upstream.h
diffstat 2 files changed, 25 insertions(+), 8 deletions(-) [+]
line wrap: on
line diff
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -2702,6 +2702,10 @@ ngx_http_upstream_intercept_errors(ngx_h
 
             if (r->cache) {
 
+                if (u->headers_in.no_cache || u->headers_in.expired) {
+                    u->cacheable = 0;
+                }
+
                 if (u->cacheable) {
                     time_t  valid;
 
@@ -2796,6 +2800,10 @@ ngx_http_upstream_process_headers(ngx_ht
 
     umcf = ngx_http_get_module_main_conf(r, ngx_http_upstream_module);
 
+    if (u->headers_in.no_cache || u->headers_in.expired) {
+        u->cacheable = 0;
+    }
+
     if (u->headers_in.x_accel_redirect
         && !(u->conf->ignore_headers & NGX_HTTP_UPSTREAM_IGN_XA_REDIRECT))
     {
@@ -4791,18 +4799,18 @@ ngx_http_upstream_process_cache_control(
         return NGX_OK;
     }
 
-    if (r->cache->valid_sec != 0 && u->headers_in.x_accel_expires != NULL) {
-        return NGX_OK;
-    }
-
     start = h->value.data;
     last = start + h->value.len;
 
+    if (r->cache->valid_sec != 0 && u->headers_in.x_accel_expires != NULL) {
+        goto extensions;
+    }
+
     if (ngx_strlcasestrn(start, last, (u_char *) "no-cache", 8 - 1) != NULL
         || ngx_strlcasestrn(start, last, (u_char *) "no-store", 8 - 1) != NULL
         || ngx_strlcasestrn(start, last, (u_char *) "private", 7 - 1) != NULL)
     {
-        u->cacheable = 0;
+        u->headers_in.no_cache = 1;
         return NGX_OK;
     }
 
@@ -4832,12 +4840,15 @@ ngx_http_upstream_process_cache_control(
         }
 
         if (n == 0) {
-            u->cacheable = 0;
+            u->headers_in.no_cache = 1;
             return NGX_OK;
         }
 
         r->cache->valid_sec = ngx_time() + n;
-    }
+        u->headers_in.expired = 0;
+    }
+
+extensions:
 
     p = ngx_strlcasestrn(start, last, (u_char *) "stale-while-revalidate=",
                          23 - 1);
@@ -4932,7 +4943,7 @@ ngx_http_upstream_process_expires(ngx_ht
     expires = ngx_parse_http_time(h->value.data, h->value.len);
 
     if (expires == NGX_ERROR || expires < ngx_time()) {
-        u->cacheable = 0;
+        u->headers_in.expired = 1;
         return NGX_OK;
     }
 
@@ -4996,6 +5007,8 @@ ngx_http_upstream_process_accel_expires(
 
         default:
             r->cache->valid_sec = ngx_time() + n;
+            u->headers_in.no_cache = 0;
+            u->headers_in.expired = 0;
             return NGX_OK;
         }
     }
@@ -5007,6 +5020,8 @@ ngx_http_upstream_process_accel_expires(
 
     if (n != NGX_ERROR) {
         r->cache->valid_sec = n;
+        u->headers_in.no_cache = 0;
+        u->headers_in.expired = 0;
     }
     }
 #endif
--- a/src/http/ngx_http_upstream.h
+++ b/src/http/ngx_http_upstream.h
@@ -293,6 +293,8 @@ typedef struct {
 
     unsigned                         connection_close:1;
     unsigned                         chunked:1;
+    unsigned                         no_cache:1;
+    unsigned                         expired:1;
 } ngx_http_upstream_headers_in_t;