Create a Liquid Handler for Rails 3.1

Back in the days with rails 2 you could easily create a handler for liquid and have access to the instance variables you’ve created in your controller. However, the creators of liquid didn’t like this approach and so when Rails 3 came out the functionality didn’t get upgraded.

I needed this functionality today for a cms I’m working on so I took some time and headaches to figure this one out.

First: Add liquid as a dependency for your app

Gemfile.rb
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gem "liquid"

Second: Create the handler

lib/action_view/template/handlers/liquid.rb
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class ActionView::Template::Handlers::Liquid
  def self.call(template)
    "ActionView::Template::Handlers::Liquid.new(self).render(#{template.source.inspect}, local_assigns)"
  end

  def initialize(view)
    @view = view
  end

  def render(template, local_assigns = {})
    @view.controller.headers["Content-Type"] ||= 'text/html; charset=utf-8'

    assigns = @view.assigns

    if @view.content_for?(:layout)
      assigns["content_for_layout"] = @view.content_for(:layout)
    end
    assigns.merge!(local_assigns.stringify_keys)

    controller = @view.controller
    filters = if controller.respond_to?(:liquid_filters, true)
                controller.send(:liquid_filters)
              elsif controller.respond_to?(:master_helper_module)
                [controller.master_helper_module]
              else
                [controller._helpers]
              end

    liquid = Liquid::Template.parse(template)
    liquid.render(assigns, :filters => filters, :registers => {:action_view => @view, :controller => @view.controller})
  end

  def compilable?
    false
  end
end

Third: Create an initializer

config/initializers/liquid_template_handler.rb
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require 'action_view/template/handlers/liquid'
ActionView::Template.register_template_handler :liquid,
  ActionView::Template::Handlers::Liquid

Fourth: Grab a beer, I just saved you 4 hours of puzzles and headaches :-)

Now you can create files like posts/index.html.liquid. In our case, we have our views in the database so we can render different views for different websites. The book Crafting Rails Applications has an extraordinary chapter that shows you how put views in your database, worth every penny.

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