Fixes #1821

CHANGELOG.md

@@ -1,6 +1,10 @@
 master
 ===
 
+* Fix directory indexes with `.htm` files. #1821
+
+# 4.1.2
+
 * Add `page_id` concept. Using the `id` key in frontmatter, proxy or page will set an ID on a resource which can be referenced by `url_for` and `link_to`.
 * Allow looking for `Gemfile` when setting up a project to fail gracefully.
 * Send correct exit code when external_pipeline fails during build.

middleman-core/lib/middleman-core/extensions/directory_indexes.rb

@@ -11,16 +11,22 @@ class Middleman::Extensions::DirectoryIndexes < ::Middleman::Extension
     index_file = app.config[:index_file]
     new_index_path = "/#{index_file}"
 
+    extensions = %w(.htm .html .php)
+
     resources.each do |resource|
       # Check if it would be pointless to reroute
       next if resource.destination_path == index_file ||
               resource.destination_path.end_with?(new_index_path) ||
-              File.extname(index_file) != resource.ext
+              !extensions.include?(resource.ext)
 
       # Check if file metadata (options set by "page" in config.rb or frontmatter) turns directory_index off
       next if resource.options[:directory_index] == false
 
-      resource.destination_path = resource.destination_path.chomp(File.extname(index_file)) + new_index_path
+      extensions.each do |ext|
+        resource.destination_path = resource.destination_path.chomp(ext)
+      end
+
+      resource.destination_path += new_index_path
     end
   end
 end