How can I render a template outside of a controller in Rails 3?

Question

I can't seem to render a template outside of a controller in my Rails 3 application. The googling I've done has been helpful, and I eventually found some useful info at http://www.swombat.com/rails-rendering-templates-outside-of-a-contro. However, this seems to be broken in Rails 3. Does anyone have any ideas how I can fix this method or perhaps know of a better approach?

My method:

  def render_erb(template_path, params)  
   view = ActionView::Base.new(ActionController::Base.view_paths, {})  

   class << view  
    include ApplicationHelper  
   end  

   view.render(:file => "#{template_path}.html.erb", :locals => params)  
  end

The error:

ActionView::Template::Error: ActionView::Template::Error
    from /Library/Ruby/Gems/1.8/gems/activesupport-3.0.0/lib/active_support/whiny_nil.rb:48:in `method_missing'
    from /Users/mikegerstenblatt/Desktop/bluetrain/lib/test.html.erb:17:in `_lib_test_html_erb__366962844_2173671680_68830'
    from /Library/Ruby/Gems/1.8/gems/actionpack-3.0.0/lib/action_view/template.rb:135:in `send'
    from /Library/Ruby/Gems/1.8/gems/actionpack-3.0.0/lib/action_view/template.rb:135:in `render'
    from /Library/Ruby/Gems/1.8/gems/activesupport-3.0.0/lib/active_support/notifications.rb:54:in `instrument'
    from /Library/Ruby/Gems/1.8/gems/actionpack-3.0.0/lib/action_view/template.rb:127:in `render'
    from /Library/Ruby/Gems/1.8/gems/actionpack-3.0.0/lib/action_view/render/rendering.rb:59:in `_render_template'
    from /Library/Ruby/Gems/1.8/gems/activesupport-3.0.0/lib/active_support/notifications.rb:52:in `instrument'
    from /Library/Ruby/Gems/1.8/gems/activesupport-3.0.0/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
    from /Library/Ruby/Gems/1.8/gems/activesupport-3.0.0/lib/active_support/notifications.rb:52:in `instrument'
    from /Library/Ruby/Gems/1.8/gems/actionpack-3.0.0/lib/action_view/render/rendering.rb:56:in `_render_template'
    from /Library/Ruby/Gems/1.8/gems/actionpack-3.0.0/lib/action_view/render/rendering.rb:26:in `render'
    from /Users/mikegerstenblatt/Desktop/bluetrain/app/models/generated_website.rb:45:in `render_erb'
    from (irb):2

Answer 1

I made a blog post and a gist that explains it.

Essentially you need to do this:

class HelloWorldController < AbstractController::Base
  include AbstractController::Rendering
  include AbstractController::Layouts
  include AbstractController::Helpers
  include AbstractController::Translation
  include AbstractController::AssetPaths
  include ActionController::UrlWriter

  self.view_paths = "app/views"

  def show; end
end

and then:

HelloWorldController.new.show

will return view rendered to a String.

Answer 2

You can use render_anywhere gem to render the template outside of controller. https://github.com/yappbox/render_anywhere