nginx 0.7.48 *) Feature: the "proxy_cache_key" directive. *) Bugfix: now nginx takes into account the "X-Accel-Expires", "Expires", and "Cache-Control" header lines in a backend response. *) Bugfix: now nginx caches responses for the GET requests only. *) Bugfix: the "fastcgi_cache_key" directive was not inherited. *) Bugfix: the $arg_... variables did not work with SSI subrequests. Thanks to Maxim Dounin. *) Bugfix: nginx could not be built with uclibc library. Thanks to Timothy Redaelli. *) Bugfix: nginx could not be built on OpenBSD; the bug had appeared in 0.7.46.

--- a/src/http/modules/ngx_http_fastcgi_module.c
+++ b/src/http/modules/ngx_http_fastcgi_module.c
@@ -2064,6 +2064,10 @@ ngx_http_fastcgi_merge_loc_conf(ngx_conf
     ngx_conf_merge_ptr_value(conf->upstream.cache_valid,
                              prev->upstream.cache_valid, NULL);
 
+    if (conf->cache_key.value.data == NULL) {
+        conf->cache_key = prev->cache_key;
+    }
+
 #endif
 
     ngx_conf_merge_value(conf->upstream.pass_request_headers,