diff --git a/nginx/nginx.conf b/nginx/nginx.conf
index 99c4899b1d0e7c31ad61f42ba2f5f1b38b4ffb30..9b85d572ab7322bfc2f5b45d1937d28f89c93ef0 100644
--- a/nginx/nginx.conf
+++ b/nginx/nginx.conf
@@ -8,6 +8,18 @@ events {
     worker_connections  1024;
 }
 
+map $time_iso8601 $year {
+    default '0000';
+    "~^(\d{4})-(\d{2})-(\d{2})" $1;
+}
+map $time_iso8601 $month {
+    default '00';
+    "~^(\d{4})-(\d{2})-(\d{2})" $2;
+}
+map $time_iso8601 $day {
+    default '00';
+    "~^(\d{4})-(\d{2})-(\d{2})" $3;
+}
 
 http {
     proxy_temp_path /tmp/proxy_temp;