module Roda::RodaPlugins::TimestampPublic::InstanceMethods

so this should not be called with untrusted input.
This does not check the file is inside the directory for performance reasons,
Return a path to the static file that could be served by r.timestamp_public.

def timestamp_path(file)
  mtime = File.mtime(File.join(opts[:public_root], file))
  "/#{opts[:timestamp_public_prefix]}/#{sprintf("%i%06i", mtime.to_i, mtime.usec)}/#{file}"
end