title: How can I check modified date of file in nginx lua script?
body: <p>all</p>
  
  <p>I'm creating a simple service to return content of a file. This is very straightforward except that the service should return 404 if the file is outdated. I'm thinking to use Nginx Lua script to check the file date. Unfortunately, I didn't see such API to get modified date of file in <a href="http://www.lua.org/manual/5.3/manual.html#6.8" rel="nofollow">standard IO module</a> </p>
  
  <p>Please let me know if there is a way to do it in Nginx. Thanks!</p>