Rendering XML with Rails

I had to code a webservice with Rails yesterday. Its obvious purpose was to respond with XML formatted data to an HTTP GET request. I looked at some of the examples out there and ran into trouble. I lost some time searching for a solution, so here's the summary of the solution to save others the hassle.

Here's what people recommend doing to render XML from a HTTP request in Rails:

class WebServiceController < ApplicationController

 def people
  @people = Person.find :all
  respond do |format|
   format.xml
  end
 end

end

And the corresponding people.xml.builder in /views/web_service/:

xml.instruct! :xml, :version=>"1.0"

xml.people do
  @people.each do |person|
    xml.person do
        xml.firstname person.first_name
        xml.lastname person.last_name
        xml.age person.age
    end
  end
end

When testing this, I kept getting browser errors about invalid XML. When I looked at the data that was returned from my webservice call, I realised that the XML was generated like I wanted, but it was subsequently embedded into the application layout I am using for all of the views (views/layouts/application.rhtml).

The issue was resolved by changing my controller code to

class WebServiceController < ApplicationController

 def people
  @people = Person.find :all
  render :template => 'web_service/people.xml.builder', :layout => false
 end

end