1 files changed, 14 insertions, 0 deletions

diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 87aa82c..0d28661 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -15,4 +15,18 @@ module ApplicationHelper
   def resolve_kind_text(value)
     value.respond_to?(:call) ? value.call : value
   end
+
+  # Cache-busts a static file living directly under public/, outside the
+  # asset pipeline -- used by both the admin and public layouts, since
+  # neither loads its static CSS/JS through Sprockets (admin_bundle.js is
+  # the one exception; it already gets pipeline fingerprinting for free).
+  # Raises rather than silently omitting the version param: a missing
+  # file here means the page is already broken, and failing loudly beats
+  # a confusing "why is the browser still showing the old version" report
+  # days later.
+  def mtime_busted_path(path)
+    file = Rails.public_path.join(path.sub(%r{\A/}, ""))
+    raise "Static asset not found for cache-busting: #{path} (looked for #{file})" unless File.exist?(file)
+    "#{path}?v=#{File.mtime(file).to_i}"
+  end
 end