ngx_http_lua_ngx_response_time.patch

diff --git a/src/ngx_http_lua_hook.c b/src/ngx_http_lua_hook.c
index b36d751..2d8a017 100644
--- a/src/ngx_http_lua_hook.c
+++ b/src/ngx_http_lua_hook.c
@@ -1671,6 +1671,37 @@ ngx_http_lua_ngx_time(lua_State *L)
 
 
 int
+ngx_http_lua_ngx_response_time(lua_State *L)
+{
+    ngx_http_request_t      *r;
+    ngx_time_t              *tp;
+    ngx_msec_int_t          ms;
+
+    lua_getglobal(L, GLOBALS_SYMBOL_REQUEST);
+    r = lua_touserdata(L, -1);
+    lua_pop(L, 1);
+
+    if (r == NULL) {
+        return luaL_error(L, "no request object found");
+    }
+
+    if (lua_gettop(L) > 0) {
+        return luaL_error(L, "shouldn't have argument");
+    }
+
+    tp = ngx_timeofday();
+
+    ms = (ngx_msec_int_t)
+             ((tp->sec - r->start_sec) * 1000 + (tp->msec - r->start_msec));
+    ms = (ms >= 0) ? ms : 0;
+
+    lua_pushnumber(L, (lua_Number) ms);
+
+    return 1;
+}
+
+
+int
 ngx_http_lua_ngx_utctime(lua_State *L)
 {
     ngx_http_request_t      *r;