Rails route that works with: http://localhost:3000/posts/tag/Drupal%205.x

gistfile1.rb

# I created a Post controller to accept a parameter for tag name.
# The problem is, the tag "Drupal 6.x", or anything with a period was triggering :format

get 'posts/tag/:tag' => 'posts#tag', :format => false, :constraints => {:tag => /.*/}