diff --git a/lualib/http/httpd.lua b/lualib/http/httpd.lua
index 66431894..c19d4bae 100644
--- a/lualib/http/httpd.lua
+++ b/lualib/http/httpd.lua
@@ -1,6 +1,7 @@
 local internal = require "http.internal"
 
 local table = table
+local string = string
 
 local httpd = {}