Upstream: different header lists for cached and uncached requests.

The upstream modules remove and alter a number of client headers
before sending the request to upstream.  This set of headers is
smaller or even empty when cache is disabled.

It's still possible that a request in a cache-enabled location is
uncached, for example, if cache entry counter is below min_uses.
In this case it's better to alter a smaller set of headers and
pass more client headers to backend unchanged.  One of the benefits
is enabling server-side byte ranges in such requests.

1 files changed, 34 insertions, 29 deletions

diff --git a/src/http/modules/ngx_http_fastcgi_module.c b/src/http/modules/ngx_http_fastcgi_module.c
index 1e0043175..cc93570b1 100644
--- a/src/http/modules/ngx_http_fastcgi_module.c
+++ b/src/http/modules/ngx_http_fastcgi_module.c
@@ -25,6 +25,9 @@ typedef struct {
     ngx_str_t                      index;
 
     ngx_http_fastcgi_params_t      params;
+#if (NGX_HTTP_CACHE)
+    ngx_http_fastcgi_params_t      params_cache;
+#endif
 
     ngx_array_t                   *params_source;
     ngx_array_t                   *catch_stderr;
@@ -156,7 +159,8 @@ static void *ngx_http_fastcgi_create_loc_conf(ngx_conf_t *cf);
 static char *ngx_http_fastcgi_merge_loc_conf(ngx_conf_t *cf,
     void *parent, void *child);
 static ngx_int_t ngx_http_fastcgi_init_params(ngx_conf_t *cf,
-    ngx_http_fastcgi_loc_conf_t *conf, ngx_http_fastcgi_params_t *params);
+    ngx_http_fastcgi_loc_conf_t *conf, ngx_http_fastcgi_params_t *params,
+    ngx_keyval_t *default_params);
 
 static ngx_int_t ngx_http_fastcgi_script_name_variable(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
@@ -795,7 +799,11 @@ ngx_http_fastcgi_create_request(ngx_http_request_t *r)
 
     flcf = ngx_http_get_module_loc_conf(r, ngx_http_fastcgi_module);
 
+#if (NGX_HTTP_CACHE)
+    params = r->upstream->cacheable ? &flcf->params_cache : &flcf->params;
+#else
     params = &flcf->params;
+#endif
 
     if (params->lengths) {
         ngx_memzero(&le, sizeof(ngx_http_script_engine_t));
@@ -2420,6 +2428,7 @@ ngx_http_fastcgi_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
     ngx_http_fastcgi_loc_conf_t *conf = child;
 
     size_t                        size;
+    ngx_int_t                     rc;
     ngx_hash_init_t               hash;
     ngx_http_core_loc_conf_t     *clcf;
 
@@ -2712,39 +2721,47 @@ ngx_http_fastcgi_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
 #endif
 
     if (conf->params_source == NULL) {
-        conf->params_source = prev->params_source;
-
+        conf->params = prev->params;
 #if (NGX_HTTP_CACHE)
-        if ((conf->upstream.cache == NULL) == (prev->upstream.cache == NULL))
+        conf->params_cache = prev->params_cache;
 #endif
-        {
-            conf->params = prev->params;
-        }
+        conf->params_source = prev->params_source;
     }
 
-    if (ngx_http_fastcgi_init_params(cf, conf, &conf->params) != NGX_OK) {
+    rc = ngx_http_fastcgi_init_params(cf, conf, &conf->params, NULL);
+    if (rc != NGX_OK) {
         return NGX_CONF_ERROR;
     }
 
+#if (NGX_HTTP_CACHE)
+
+    if (conf->upstream.cache) {
+        rc = ngx_http_fastcgi_init_params(cf, conf, &conf->params_cache,
+                                          ngx_http_fastcgi_cache_headers);
+        if (rc != NGX_OK) {
+            return NGX_CONF_ERROR;
+        }
+    }
+
+#endif
+
     return NGX_CONF_OK;
 }
 
 
 static ngx_int_t
 ngx_http_fastcgi_init_params(ngx_conf_t *cf, ngx_http_fastcgi_loc_conf_t *conf,
-    ngx_http_fastcgi_params_t *params)
+    ngx_http_fastcgi_params_t *params, ngx_keyval_t *default_params)
 {
     u_char                       *p;
     size_t                        size;
     uintptr_t                    *code;
     ngx_uint_t                    i, nsrc;
-    ngx_array_t                   headers_names;
-#if (NGX_HTTP_CACHE)
-    ngx_array_t                   params_merged;
-#endif
+    ngx_array_t                   headers_names, params_merged;
+    ngx_keyval_t                 *h;
     ngx_hash_key_t               *hk;
     ngx_hash_init_t               hash;
-    ngx_http_upstream_param_t    *src;
+    ngx_http_upstream_param_t    *src, *s;
     ngx_http_script_compile_t     sc;
     ngx_http_script_copy_code_t  *copy;
 
@@ -2752,12 +2769,7 @@ ngx_http_fastcgi_init_params(ngx_conf_t *cf, ngx_http_fastcgi_loc_conf_t *conf,
         return NGX_OK;
     }
 
-    if (conf->params_source == NULL
-#if (NGX_HTTP_CACHE)
-        && (conf->upstream.cache == NULL)
-#endif
-       )
-    {
+    if (conf->params_source == NULL && default_params == NULL) {
         params->hash.buckets = (void *) 1;
         return NGX_OK;
     }
@@ -2787,12 +2799,7 @@ ngx_http_fastcgi_init_params(ngx_conf_t *cf, ngx_http_fastcgi_loc_conf_t *conf,
         nsrc = 0;
     }
 
-#if (NGX_HTTP_CACHE)
-
-    if (conf->upstream.cache) {
-        ngx_keyval_t               *h;
-        ngx_http_upstream_param_t  *s;
-
+    if (default_params) {
         if (ngx_array_init(&params_merged, cf->temp_pool, 4,
                            sizeof(ngx_http_upstream_param_t))
             != NGX_OK)
@@ -2810,7 +2817,7 @@ ngx_http_fastcgi_init_params(ngx_conf_t *cf, ngx_http_fastcgi_loc_conf_t *conf,
             *s = src[i];
         }
 
-        h = ngx_http_fastcgi_cache_headers;
+        h = default_params;
 
         while (h->key.len) {
 
@@ -2841,8 +2848,6 @@ ngx_http_fastcgi_init_params(ngx_conf_t *cf, ngx_http_fastcgi_loc_conf_t *conf,
         nsrc = params_merged.nelts;
     }
 
-#endif
-
     for (i = 0; i < nsrc; i++) {
 
         if (src[i].key.len > sizeof("HTTP_") - 1