title: Rails 3 respond_to: default format?
body: <p>I am converting a Rails 2 application to Rails 3. I currently have a controller set up like the following:</p>
  
  <pre><code>class Api::RegionsController &lt; ApplicationController
    respond_to :xml, :json
  end
  </code></pre>
  
  <p>with and an action that looks like the following:</p>
  
  <pre><code>def index
    @regions = Region.all
  
    respond_with @regions  
  end
  </code></pre>
  
  <p>The implementation is pretty straightforward, api/regions, api/regions.xml and api/regions.json all respond as you would expect. The problem is that I want api/regions by default to respond via XML. I have consumers that expect an XML response and I would hate to have them change all their URLs to include .xml unless absolutely necessary. </p>
  
  <p>In Rails 2 you would accomplish that by doing this:</p>
  
  <pre><code>respond_to do |format|
    format.xml { render :xml =&gt; @region.to_xml }
    format.json { render :json =&gt; @region.to_json }
  end
  </code></pre>
  
  <p>But in Rails 3 I cannot find a way to default it to an XML response. Any ideas?</p>