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Makes routing in Rails case-insensitive (and other Rack-servers like Sinatra)

This gem hooks into the Rack middleware of Rails. This way all paths are downcased before dispatching to Rails' routing mechanism. Querystring parameters and asset paths are not changed in any way.


This gem is tested with 5.0.x, 5.1.x, 5.2.x. It reportedly also works with Sinata, although I do not use Sinatra myself. Sinatra test-cases will be most welcome.

If you want this functionality in a Rails 2.x-3.0 application, please refer to this blog post. If you need it for Rails 3.1.x or 4.x version 1.2.2 should serve you just fine.

Note: from version 1.2.0, route_downcaser depends on ActiveSupport 3.2 or later. This was necessary to enable support for multibyte characters.



Just add the gem to your gemfile and run bundle

gem 'route_downcaser'

Then restart your Rails server. No configuration is needed. The gem simply hooks itself into the Rack middleware call stack.

If you have a controller named app/controllers/foo_controller.rb and the action index, you can now call it with:


All the above are valid.


In your Gemfile you add the gem:

gem 'route_downcaser'

In your application.rb you add the following (after loading Sinatra)

require 'route_downcaser'
use RouteDowncaser::DowncaseRouteMiddleware

Now this statement

get '/foo' do

will respond to all these requests:


Configuration Options

Configuration options can be set using an initializer in your application like so:

# config/initializers/route_downcaser.rb

RouteDowncaser.configuration do |config|
  config.redirect = true

  config.exclude_patterns = [


With this configuration option set to `true`, the middleware will 301 redirect all routes to their downcased version. Example: `localhost:3000/Foo` will redirect to `localhost:3000/foo`.


Array of regular expressions. If the requested path matches one of these expressions, RouteDowncaser will not change anything.

Background information

Sometimes you may wish to market a url which contains a controller name - like If this is done on offline media it will cause potential customers trouble, if they don't use the correct casing. If, for some reason, the user types (with capital S), your Rails app will return a 404 not found.

The strange thing is, that the W3C specification states:

URLs in general are case-sensitive (with the exception of machine names). There may be URLs, or parts of URLs, where case doesn't matter, but identifying these may not be easy. Users should always consider that URLs are case-sensitive.

So is case-insensitive and can be written as WWW.MYSHOP.COM, but the path (/specialoffer) is not.

It may make perfect sense for the W3C guys, but not for the average user.

When Rails introduced Rack middleware, it suddenly became possible to hook into the call-stack before the URL is used for action dispatching.

At first I just made this code as a snippet and published it on my blog. But since I found out that many people are actually using this, I finally decided to convert it into a gem.

All it really does is to take the path and downcase it before dispatching. Querystring parameters are NOT touched, they keep their casing, since it may have some contextual meaning.