Variables: generic prefix variables.

9 files changed, 266 insertions, 162 deletions

diff --git a/src/http/modules/ngx_http_rewrite_module.c b/src/http/modules/ngx_http_rewrite_module.c
index 6b2444cbd..a6f1fc820 100644
--- a/src/http/modules/ngx_http_rewrite_module.c
+++ b/src/http/modules/ngx_http_rewrite_module.c
@@ -917,7 +917,8 @@ ngx_http_rewrite_set(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
     value[1].len--;
     value[1].data++;
 
-    v = ngx_http_add_variable(cf, &value[1], NGX_HTTP_VAR_CHANGEABLE);
+    v = ngx_http_add_variable(cf, &value[1],
+                              NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_WEAK);
     if (v == NULL) {
         return NGX_CONF_ERROR;
     }
@@ -927,15 +928,7 @@ ngx_http_rewrite_set(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
         return NGX_CONF_ERROR;
     }
 
-    if (v->get_handler == NULL
-        && ngx_strncasecmp(value[1].data, (u_char *) "http_", 5) != 0
-        && ngx_strncasecmp(value[1].data, (u_char *) "sent_http_", 10) != 0
-        && ngx_strncasecmp(value[1].data, (u_char *) "upstream_http_", 14) != 0
-        && ngx_strncasecmp(value[1].data, (u_char *) "cookie_", 7) != 0
-        && ngx_strncasecmp(value[1].data, (u_char *) "upstream_cookie_", 16)
-           != 0
-        && ngx_strncasecmp(value[1].data, (u_char *) "arg_", 4) != 0)
-    {
+    if (v->get_handler == NULL) {
         v->get_handler = ngx_http_rewrite_var;
         v->data = index;
     }
diff --git a/src/http/ngx_http_core_module.h b/src/http/ngx_http_core_module.h
index 70e693a6b..5018da09a 100644
--- a/src/http/ngx_http_core_module.h
+++ b/src/http/ngx_http_core_module.h
@@ -158,7 +158,8 @@ typedef struct {
 
     ngx_hash_t                 variables_hash;
 
-    ngx_array_t                variables;       /* ngx_http_variable_t */
+    ngx_array_t                variables;         /* ngx_http_variable_t */
+    ngx_array_t                prefix_variables;  /* ngx_http_variable_t */
     ngx_uint_t                 ncaptures;
 
     ngx_uint_t                 server_names_hash_max_size;
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index 74a7c64b0..c59519416 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -162,6 +162,10 @@ static ngx_int_t ngx_http_upstream_response_time_variable(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_http_upstream_response_length_variable(
     ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data);
+static ngx_int_t ngx_http_upstream_header_variable(ngx_http_request_t *r,
+    ngx_http_variable_value_t *v, uintptr_t data);
+static ngx_int_t ngx_http_upstream_cookie_variable(ngx_http_request_t *r,
+    ngx_http_variable_value_t *v, uintptr_t data);
 
 static char *ngx_http_upstream(ngx_conf_t *cf, ngx_command_t *cmd, void *dummy);
 static char *ngx_http_upstream_server(ngx_conf_t *cf, ngx_command_t *cmd,
@@ -413,6 +417,12 @@ static ngx_http_variable_t  ngx_http_upstream_vars[] = {
 
 #endif
 
+    { ngx_string("upstream_http_"), NULL, ngx_http_upstream_header_variable,
+      0, NGX_HTTP_VAR_NOCACHEABLE|NGX_HTTP_VAR_PREFIX, 0 },
+
+    { ngx_string("upstream_cookie_"), NULL, ngx_http_upstream_cookie_variable,
+      0, NGX_HTTP_VAR_NOCACHEABLE|NGX_HTTP_VAR_PREFIX, 0 },
+
     { ngx_null_string, NULL, NULL, 0, 0, 0 }
 };
 
@@ -5391,7 +5401,7 @@ ngx_http_upstream_response_length_variable(ngx_http_request_t *r,
 }
 
 
-ngx_int_t
+static ngx_int_t
 ngx_http_upstream_header_variable(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data)
 {
@@ -5406,7 +5416,7 @@ ngx_http_upstream_header_variable(ngx_http_request_t *r,
 }
 
 
-ngx_int_t
+static ngx_int_t
 ngx_http_upstream_cookie_variable(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data)
 {
diff --git a/src/http/ngx_http_upstream.h b/src/http/ngx_http_upstream.h
index 86e2ee223..7f601ee0b 100644
--- a/src/http/ngx_http_upstream.h
+++ b/src/http/ngx_http_upstream.h
@@ -402,11 +402,6 @@ typedef struct {
 } ngx_http_upstream_param_t;
 
 
-ngx_int_t ngx_http_upstream_cookie_variable(ngx_http_request_t *r,
-    ngx_http_variable_value_t *v, uintptr_t data);
-ngx_int_t ngx_http_upstream_header_variable(ngx_http_request_t *r,
-    ngx_http_variable_value_t *v, uintptr_t data);
-
 ngx_int_t ngx_http_upstream_create(ngx_http_request_t *r);
 void ngx_http_upstream_init(ngx_http_request_t *r);
 ngx_http_upstream_srv_conf_t *ngx_http_upstream_add(ngx_conf_t *cf,
diff --git a/src/http/ngx_http_variables.c b/src/http/ngx_http_variables.c
index 62006ba93..6138819dd 100644
--- a/src/http/ngx_http_variables.c
+++ b/src/http/ngx_http_variables.c
@@ -11,6 +11,9 @@
 #include <nginx.h>
 
 
+static ngx_http_variable_t *ngx_http_add_prefix_variable(ngx_conf_t *cf,
+    ngx_str_t *name, ngx_uint_t flags);
+
 static ngx_int_t ngx_http_variable_request(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
 #if 0
@@ -356,6 +359,18 @@ static ngx_http_variable_t  ngx_http_core_variables[] = {
       3, NGX_HTTP_VAR_NOCACHEABLE, 0 },
 #endif
 
+    { ngx_string("http_"), NULL, ngx_http_variable_unknown_header_in,
+      0, NGX_HTTP_VAR_PREFIX, 0 },
+
+    { ngx_string("sent_http_"), NULL, ngx_http_variable_unknown_header_out,
+      0, NGX_HTTP_VAR_PREFIX, 0 },
+
+    { ngx_string("cookie_"), NULL, ngx_http_variable_cookie,
+      0, NGX_HTTP_VAR_PREFIX, 0 },
+
+    { ngx_string("arg_"), NULL, ngx_http_variable_argument,
+      0, NGX_HTTP_VAR_NOCACHEABLE|NGX_HTTP_VAR_PREFIX, 0 },
+
     { ngx_null_string, NULL, NULL, 0, 0, 0 }
 };
 
@@ -384,6 +399,10 @@ ngx_http_add_variable(ngx_conf_t *cf, ngx_str_t *name, ngx_uint_t flags)
         return NULL;
     }
 
+    if (flags & NGX_HTTP_VAR_PREFIX) {
+        return ngx_http_add_prefix_variable(cf, name, flags);
+    }
+
     cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
 
     key = cmcf->variables_keys->keys.elts;
@@ -402,6 +421,8 @@ ngx_http_add_variable(ngx_conf_t *cf, ngx_str_t *name, ngx_uint_t flags)
             return NULL;
         }
 
+        v->flags &= flags | ~NGX_HTTP_VAR_WEAK;
+
         return v;
     }
 
@@ -440,6 +461,59 @@ ngx_http_add_variable(ngx_conf_t *cf, ngx_str_t *name, ngx_uint_t flags)
 }
 
 
+static ngx_http_variable_t *
+ngx_http_add_prefix_variable(ngx_conf_t *cf, ngx_str_t *name, ngx_uint_t flags)
+{
+    ngx_uint_t                  i;
+    ngx_http_variable_t        *v;
+    ngx_http_core_main_conf_t  *cmcf;
+
+    cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
+
+    v = cmcf->prefix_variables.elts;
+    for (i = 0; i < cmcf->prefix_variables.nelts; i++) {
+        if (name->len != v[i].name.len
+            || ngx_strncasecmp(name->data, v[i].name.data, name->len) != 0)
+        {
+            continue;
+        }
+
+        v = &v[i];
+
+        if (!(v->flags & NGX_HTTP_VAR_CHANGEABLE)) {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                               "the duplicate \"%V\" variable", name);
+            return NULL;
+        }
+
+        v->flags &= flags | ~NGX_HTTP_VAR_WEAK;
+
+        return v;
+    }
+
+    v = ngx_array_push(&cmcf->prefix_variables);
+    if (v == NULL) {
+        return NULL;
+    }
+
+    v->name.len = name->len;
+    v->name.data = ngx_pnalloc(cf->pool, name->len);
+    if (v->name.data == NULL) {
+        return NULL;
+    }
+
+    ngx_strlow(v->name.data, name->data, name->len);
+
+    v->set_handler = NULL;
+    v->get_handler = NULL;
+    v->data = 0;
+    v->flags = flags;
+    v->index = 0;
+
+    return v;
+}
+
+
 ngx_int_t
 ngx_http_get_variable_index(ngx_conf_t *cf, ngx_str_t *name)
 {
@@ -573,6 +647,8 @@ ngx_http_get_flushed_variable(ngx_http_request_t *r, ngx_uint_t index)
 ngx_http_variable_value_t *
 ngx_http_get_variable(ngx_http_request_t *r, ngx_str_t *name, ngx_uint_t key)
 {
+    size_t                      len;
+    ngx_uint_t                  i, n;
     ngx_http_variable_t        *v;
     ngx_http_variable_value_t  *vv;
     ngx_http_core_main_conf_t  *cmcf;
@@ -610,64 +686,22 @@ ngx_http_get_variable(ngx_http_request_t *r, ngx_str_t *name, ngx_uint_t key)
         return NULL;
     }
 
-    if (name->len >= 5 && ngx_strncmp(name->data, "http_", 5) == 0) {
-
-        if (ngx_http_variable_unknown_header_in(r, vv, (uintptr_t) name)
-            == NGX_OK)
-        {
-            return vv;
-        }
-
-        return NULL;
-    }
-
-    if (name->len >= 10 && ngx_strncmp(name->data, "sent_http_", 10) == 0) {
-
-        if (ngx_http_variable_unknown_header_out(r, vv, (uintptr_t) name)
-            == NGX_OK)
-        {
-            return vv;
-        }
-
-        return NULL;
-    }
-
-    if (name->len >= 14 && ngx_strncmp(name->data, "upstream_http_", 14) == 0) {
-
-        if (ngx_http_upstream_header_variable(r, vv, (uintptr_t) name)
-            == NGX_OK)
-        {
-            return vv;
-        }
-
-        return NULL;
-    }
-
-    if (name->len >= 7 && ngx_strncmp(name->data, "cookie_", 7) == 0) {
-
-        if (ngx_http_variable_cookie(r, vv, (uintptr_t) name) == NGX_OK) {
-            return vv;
-        }
-
-        return NULL;
-    }
+    len = 0;
 
-    if (name->len >= 16
-        && ngx_strncmp(name->data, "upstream_cookie_", 16) == 0)
-    {
+    v = cmcf->prefix_variables.elts;
+    n = cmcf->prefix_variables.nelts;
 
-        if (ngx_http_upstream_cookie_variable(r, vv, (uintptr_t) name)
-            == NGX_OK)
+    for (i = 0; i < cmcf->prefix_variables.nelts; i++) {
+        if (name->len >= v[i].name.len && name->len > len
+            && ngx_strncmp(name->data, v[i].name.data, v[i].name.len) == 0)
         {
-            return vv;
+            len = v[i].name.len;
+            n = i;
         }
-
-        return NULL;
     }
 
-    if (name->len >= 4 && ngx_strncmp(name->data, "arg_", 4) == 0) {
-
-        if (ngx_http_variable_argument(r, vv, (uintptr_t) name) == NGX_OK) {
+    if (n != cmcf->prefix_variables.nelts) {
+        if (v[n].get_handler(r, vv, (uintptr_t) name) == NGX_OK) {
             return vv;
         }
 
@@ -2502,7 +2536,6 @@ ngx_http_regex_exec(ngx_http_request_t *r, ngx_http_regex_t *re, ngx_str_t *s)
 ngx_int_t
 ngx_http_variables_add_core_vars(ngx_conf_t *cf)
 {
-    ngx_int_t                   rc;
     ngx_http_variable_t        *cv, *v;
     ngx_http_core_main_conf_t  *cmcf;
 
@@ -2523,27 +2556,20 @@ ngx_http_variables_add_core_vars(ngx_conf_t *cf)
         return NGX_ERROR;
     }
 
+    if (ngx_array_init(&cmcf->prefix_variables, cf->pool, 8,
+                       sizeof(ngx_http_variable_t))
+        != NGX_OK)
+    {
+        return NGX_ERROR;
+    }
+
     for (cv = ngx_http_core_variables; cv->name.len; cv++) {
-        v = ngx_palloc(cf->pool, sizeof(ngx_http_variable_t));
+        v = ngx_http_add_variable(cf, &cv->name, cv->flags);
         if (v == NULL) {
             return NGX_ERROR;
         }
 
         *v = *cv;
-
-        rc = ngx_hash_add_key(cmcf->variables_keys, &v->name, v,
-                              NGX_HASH_READONLY_KEY);
-
-        if (rc == NGX_OK) {
-            continue;
-        }
-
-        if (rc == NGX_BUSY) {
-            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
-                               "conflicting variable name \"%V\"", &v->name);
-        }
-
-        return NGX_ERROR;
     }
 
     return NGX_OK;
@@ -2553,10 +2579,11 @@ ngx_http_variables_add_core_vars(ngx_conf_t *cf)
 ngx_int_t
 ngx_http_variables_init_vars(ngx_conf_t *cf)
 {
+    size_t                      len;
     ngx_uint_t                  i, n;
     ngx_hash_key_t             *key;
     ngx_hash_init_t             hash;
-    ngx_http_variable_t        *v, *av;
+    ngx_http_variable_t        *v, *av, *pv;
     ngx_http_core_main_conf_t  *cmcf;
 
     /* set the handlers for the indexed http variables */
@@ -2564,6 +2591,7 @@ ngx_http_variables_init_vars(ngx_conf_t *cf)
     cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
 
     v = cmcf->variables.elts;
+    pv = cmcf->prefix_variables.elts;
     key = cmcf->variables_keys->keys.elts;
 
     for (i = 0; i < cmcf->variables.nelts; i++) {
@@ -2584,7 +2612,9 @@ ngx_http_variables_init_vars(ngx_conf_t *cf)
 
                 av->index = i;
 
-                if (av->get_handler == NULL) {
+                if (av->get_handler == NULL
+                    || (av->flags & NGX_HTTP_VAR_WEAK))
+                {
                     break;
                 }
 
@@ -2592,68 +2622,34 @@ ngx_http_variables_init_vars(ngx_conf_t *cf)
             }
         }
 
-        if (v[i].name.len >= 5
-            && ngx_strncmp(v[i].name.data, "http_", 5) == 0)
-        {
-            v[i].get_handler = ngx_http_variable_unknown_header_in;
-            v[i].data = (uintptr_t) &v[i].name;
-
-            continue;
-        }
-
-        if (v[i].name.len >= 10
-            && ngx_strncmp(v[i].name.data, "sent_http_", 10) == 0)
-        {
-            v[i].get_handler = ngx_http_variable_unknown_header_out;
-            v[i].data = (uintptr_t) &v[i].name;
-
-            continue;
-        }
-
-        if (v[i].name.len >= 14
-            && ngx_strncmp(v[i].name.data, "upstream_http_", 14) == 0)
-        {
-            v[i].get_handler = ngx_http_upstream_header_variable;
-            v[i].data = (uintptr_t) &v[i].name;
-            v[i].flags = NGX_HTTP_VAR_NOCACHEABLE;
-
-            continue;
-        }
-
-        if (v[i].name.len >= 7
-            && ngx_strncmp(v[i].name.data, "cookie_", 7) == 0)
-        {
-            v[i].get_handler = ngx_http_variable_cookie;
-            v[i].data = (uintptr_t) &v[i].name;
+        len = 0;
+        av = NULL;
 
-            continue;
+        for (n = 0; n < cmcf->prefix_variables.nelts; n++) {
+            if (v[i].name.len >= pv[n].name.len && v[i].name.len > len
+                && ngx_strncmp(v[i].name.data, pv[n].name.data, pv[n].name.len)
+                   == 0)
+            {
+                av = &pv[n];
+                len = pv[n].name.len;
+            }
         }
 
-        if (v[i].name.len >= 16
-            && ngx_strncmp(v[i].name.data, "upstream_cookie_", 16) == 0)
-        {
-            v[i].get_handler = ngx_http_upstream_cookie_variable;
+        if (av) {
+            v[i].get_handler = av->get_handler;
             v[i].data = (uintptr_t) &v[i].name;
-            v[i].flags = NGX_HTTP_VAR_NOCACHEABLE;
+            v[i].flags = av->flags;
 
-            continue;
+            goto next;
         }
 
-        if (v[i].name.len >= 4
-            && ngx_strncmp(v[i].name.data, "arg_", 4) == 0)
-        {
-            v[i].get_handler = ngx_http_variable_argument;
-            v[i].data = (uintptr_t) &v[i].name;
-            v[i].flags = NGX_HTTP_VAR_NOCACHEABLE;
+        if (v[i].get_handler == NULL) {
+            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
+                          "unknown \"%V\" variable", &v[i].name);
 
-            continue;
+            return NGX_ERROR;
         }
 
-        ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
-                      "unknown \"%V\" variable", &v[i].name);
-
-        return NGX_ERROR;
-
     next:
         continue;
     }
diff --git a/src/http/ngx_http_variables.h b/src/http/ngx_http_variables.h
index 829fab31e..df337defc 100644
--- a/src/http/ngx_http_variables.h
+++ b/src/http/ngx_http_variables.h
@@ -30,6 +30,8 @@ typedef ngx_int_t (*ngx_http_get_variable_pt) (ngx_http_request_t *r,
 #define NGX_HTTP_VAR_NOCACHEABLE  2
 #define NGX_HTTP_VAR_INDEXED      4
 #define NGX_HTTP_VAR_NOHASH       8
+#define NGX_HTTP_VAR_WEAK         16
+#define NGX_HTTP_VAR_PREFIX       32
 
 
 struct ngx_http_variable_s {
diff --git a/src/stream/ngx_stream.h b/src/stream/ngx_stream.h
index 9e4169c38..814e3b99a 100644
--- a/src/stream/ngx_stream.h
+++ b/src/stream/ngx_stream.h
@@ -153,7 +153,8 @@ typedef struct {
 
     ngx_hash_t                     variables_hash;
 
-    ngx_array_t                    variables;   /* ngx_stream_variable_t */
+    ngx_array_t                    variables;        /* ngx_stream_variable_t */
+    ngx_array_t                    prefix_variables; /* ngx_stream_variable_t */
     ngx_uint_t                     ncaptures;
 
     ngx_uint_t                     variables_hash_max_size;
diff --git a/src/stream/ngx_stream_variables.c b/src/stream/ngx_stream_variables.c
index 9dc93ee57..5d15f3a6d 100644
--- a/src/stream/ngx_stream_variables.c
+++ b/src/stream/ngx_stream_variables.c
@@ -10,6 +10,8 @@
 #include <ngx_stream.h>
 #include <nginx.h>
 
+static ngx_stream_variable_t *ngx_stream_add_prefix_variable(ngx_conf_t *cf,
+    ngx_str_t *name, ngx_uint_t flags);
 
 static ngx_int_t ngx_stream_variable_binary_remote_addr(
     ngx_stream_session_t *s, ngx_stream_variable_value_t *v, uintptr_t data);
@@ -137,6 +139,10 @@ ngx_stream_add_variable(ngx_conf_t *cf, ngx_str_t *name, ngx_uint_t flags)
         return NULL;
     }
 
+    if (flags & NGX_STREAM_VAR_PREFIX) {
+        return ngx_stream_add_prefix_variable(cf, name, flags);
+    }
+
     cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
 
     key = cmcf->variables_keys->keys.elts;
@@ -155,6 +161,8 @@ ngx_stream_add_variable(ngx_conf_t *cf, ngx_str_t *name, ngx_uint_t flags)
             return NULL;
         }
 
+        v->flags &= flags | ~NGX_STREAM_VAR_WEAK;
+
         return v;
     }
 
@@ -193,6 +201,60 @@ ngx_stream_add_variable(ngx_conf_t *cf, ngx_str_t *name, ngx_uint_t flags)
 }
 
 
+static ngx_stream_variable_t *
+ngx_stream_add_prefix_variable(ngx_conf_t *cf, ngx_str_t *name,
+    ngx_uint_t flags)
+{
+    ngx_uint_t                    i;
+    ngx_stream_variable_t        *v;
+    ngx_stream_core_main_conf_t  *cmcf;
+
+    cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
+
+    v = cmcf->prefix_variables.elts;
+    for (i = 0; i < cmcf->prefix_variables.nelts; i++) {
+        if (name->len != v[i].name.len
+            || ngx_strncasecmp(name->data, v[i].name.data, name->len) != 0)
+        {
+            continue;
+        }
+
+        v = &v[i];
+
+        if (!(v->flags & NGX_STREAM_VAR_CHANGEABLE)) {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                               "the duplicate \"%V\" variable", name);
+            return NULL;
+        }
+
+        v->flags &= flags | ~NGX_STREAM_VAR_WEAK;
+
+        return v;
+    }
+
+    v = ngx_array_push(&cmcf->prefix_variables);
+    if (v == NULL) {
+        return NULL;
+    }
+
+    v->name.len = name->len;
+    v->name.data = ngx_pnalloc(cf->pool, name->len);
+    if (v->name.data == NULL) {
+        return NULL;
+    }
+
+    ngx_strlow(v->name.data, name->data, name->len);
+
+    v->set_handler = NULL;
+    v->get_handler = NULL;
+    v->data = 0;
+    v->flags = flags;
+    v->index = 0;
+
+    return v;
+}
+
+
 ngx_int_t
 ngx_stream_get_variable_index(ngx_conf_t *cf, ngx_str_t *name)
 {
@@ -327,6 +389,8 @@ ngx_stream_variable_value_t *
 ngx_stream_get_variable(ngx_stream_session_t *s, ngx_str_t *name,
     ngx_uint_t key)
 {
+    size_t                        len;
+    ngx_uint_t                    i, n;
     ngx_stream_variable_t        *v;
     ngx_stream_variable_value_t  *vv;
     ngx_stream_core_main_conf_t  *cmcf;
@@ -365,6 +429,28 @@ ngx_stream_get_variable(ngx_stream_session_t *s, ngx_str_t *name,
         return NULL;
     }
 
+    len = 0;
+
+    v = cmcf->prefix_variables.elts;
+    n = cmcf->prefix_variables.nelts;
+
+    for (i = 0; i < cmcf->prefix_variables.nelts; i++) {
+        if (name->len >= v[i].name.len && name->len > len
+            && ngx_strncmp(name->data, v[i].name.data, v[i].name.len) == 0)
+        {
+            len = v[i].name.len;
+            n = i;
+        }
+    }
+
+    if (n != cmcf->prefix_variables.nelts) {
+        if (v[n].get_handler(s, vv, (uintptr_t) name) == NGX_OK) {
+            return vv;
+        }
+
+        return NULL;
+    }
+
     vv->not_found = 1;
 
     return vv;
@@ -1000,7 +1086,6 @@ ngx_stream_regex_exec(ngx_stream_session_t *s, ngx_stream_regex_t *re,
 ngx_int_t
 ngx_stream_variables_add_core_vars(ngx_conf_t *cf)
 {
-    ngx_int_t                     rc;
     ngx_stream_variable_t        *cv, *v;
     ngx_stream_core_main_conf_t  *cmcf;
 
@@ -1021,27 +1106,20 @@ ngx_stream_variables_add_core_vars(ngx_conf_t *cf)
         return NGX_ERROR;
     }
 
+    if (ngx_array_init(&cmcf->prefix_variables, cf->pool, 8,
+                       sizeof(ngx_stream_variable_t))
+        != NGX_OK)
+    {
+        return NGX_ERROR;
+    }
+
     for (cv = ngx_stream_core_variables; cv->name.len; cv++) {
-        v = ngx_palloc(cf->pool, sizeof(ngx_stream_variable_t));
+        v = ngx_stream_add_variable(cf, &cv->name, cv->flags);
         if (v == NULL) {
             return NGX_ERROR;
         }
 
         *v = *cv;
-
-        rc = ngx_hash_add_key(cmcf->variables_keys, &v->name, v,
-                              NGX_HASH_READONLY_KEY);
-
-        if (rc == NGX_OK) {
-            continue;
-        }
-
-        if (rc == NGX_BUSY) {
-            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
-                               "conflicting variable name \"%V\"", &v->name);
-        }
-
-        return NGX_ERROR;
     }
 
     return NGX_OK;
@@ -1051,10 +1129,11 @@ ngx_stream_variables_add_core_vars(ngx_conf_t *cf)
 ngx_int_t
 ngx_stream_variables_init_vars(ngx_conf_t *cf)
 {
+    size_t                        len;
     ngx_uint_t                    i, n;
     ngx_hash_key_t               *key;
     ngx_hash_init_t               hash;
-    ngx_stream_variable_t        *v, *av;
+    ngx_stream_variable_t        *v, *av, *pv;
     ngx_stream_core_main_conf_t  *cmcf;
 
     /* set the handlers for the indexed stream variables */
@@ -1062,6 +1141,7 @@ ngx_stream_variables_init_vars(ngx_conf_t *cf)
     cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
 
     v = cmcf->variables.elts;
+    pv = cmcf->prefix_variables.elts;
     key = cmcf->variables_keys->keys.elts;
 
     for (i = 0; i < cmcf->variables.nelts; i++) {
@@ -1082,7 +1162,9 @@ ngx_stream_variables_init_vars(ngx_conf_t *cf)
 
                 av->index = i;
 
-                if (av->get_handler == NULL) {
+                if (av->get_handler == NULL
+                    || (av->flags & NGX_STREAM_VAR_WEAK))
+                {
                     break;
                 }
 
@@ -1090,10 +1172,32 @@ ngx_stream_variables_init_vars(ngx_conf_t *cf)
             }
         }
 
-        ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
-                      "unknown \"%V\" variable", &v[i].name);
+        len = 0;
+        av = NULL;
 
-        return NGX_ERROR;
+        for (n = 0; n < cmcf->prefix_variables.nelts; n++) {
+            if (v[i].name.len >= pv[n].name.len && v[i].name.len > len
+                && ngx_strncmp(v[i].name.data, pv[n].name.data, pv[n].name.len)
+                   == 0)
+            {
+                av = &pv[n];
+                len = pv[n].name.len;
+            }
+        }
+
+        if (av) {
+            v[i].get_handler = av->get_handler;
+            v[i].data = (uintptr_t) &v[i].name;
+            v[i].flags = av->flags;
+
+            goto next;
+         }
+
+        if (v[i].get_handler == NULL) {
+            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
+                          "unknown \"%V\" variable", &v[i].name);
+            return NGX_ERROR;
+        }
 
     next:
         continue;
diff --git a/src/stream/ngx_stream_variables.h b/src/stream/ngx_stream_variables.h
index e4151e224..815511154 100644
--- a/src/stream/ngx_stream_variables.h
+++ b/src/stream/ngx_stream_variables.h
@@ -30,6 +30,8 @@ typedef ngx_int_t (*ngx_stream_get_variable_pt) (ngx_stream_session_t *s,
 #define NGX_STREAM_VAR_NOCACHEABLE  2
 #define NGX_STREAM_VAR_INDEXED      4
 #define NGX_STREAM_VAR_NOHASH       8
+#define NGX_STREAM_VAR_WEAK         16
+#define NGX_STREAM_VAR_PREFIX       32
 
 
 struct ngx_stream_variable_s {