title: Can anyone explain this snippet of `ruby`?
body: <p>Can any one explain this snippet of <code>ruby</code> ?</p>
  
  <pre><code>def request_phase
       service_url = append_params( callback_url, return_url )
      [
  
        302,
        {
          'Location' =&gt; login_url( service_url ),
          'Content-Type' =&gt; 'text/plain'
        },
        ["You are being redirected to CAS for sign-in."]
      ]
    end
  </code></pre>