OmniAuth doesn't work with Route Globbing in Rails3

Question

I am trying to follow the Railscast 241 Simple OmniAuth and it works fine unless I have Route Globbing at the end of /config/routes.rb:

match '*uri' => "posts#index"

If I request /auth/twitter with the globbing then OmniAuth does nothing:

Started GET "/auth/twitter" for 127.0.0.1 at 2011-04-03 19:17:44 +0200
  Processing by PostsController#index as HTML
  Parameters: {"uri"=>"auth/twitter"}
Rendered posts/index.html.haml within layouts/application (9.0ms)
Completed 200 OK in 103ms (Views: 14.6ms | ActiveRecord: 0.7ms)

Without the globbing route it authenticates correctly.

Is there a way to have both the route globbing and OmniAuth?

Answer 1

The OmniAuth process is to provide the following functionality when a /auth/:provider URL is called:

1. Pass the request to the underlying Rack/Rails app as if OmniAuth wasn't there;
2. Determine whether or not the underlying application generated a 404;
3. If it did, invoke the actual OmniAuth functionality.

Since you are essentially matching everything using your route globbing, your application will never give 404's, and OmniAuth cannot do it's job. I see two immediate options.

Match OmniAuth Routes to a 404 Manually

Add a new route as follows:

match '/auth/:provider' => 'omniauth#passthru'

Then create a controller and action that generates a 404:

class OmniauthController < ApplicationController
  def passthru
    render :file => "#{Rails.root}/public/404.html", :status => 404, :layout => false
  end
end

Determine 404 Status in the Glob Route

I assume that your glob route will search for a post matching the URL somehow; you can take misses (e.g. when PostsController#index can't find a post) and generate 404's then.

class PostsController < ApplicationController
  def index
    if @posts = Post.find_by_current_url_or_whatever
      render 'index'
    else
      render :file => "#{Rails.root}/public/404.html", :status => 404, :layout => false
    end
  end
end