Rails 3: How to render ERb template in rake task?

Question

I am rendering a pretty huge sitemap HTML file with rake. Unfortunately, the code breaks when I migrate to rails 3. My current code looks like this:

@controller = ActionController::Base.new
@controller.request = ActionController::TestRequest.new
@controller.instance_eval do
  @url = ActionController::UrlRewriter.new(request, {})
end

# collect data, open output file file

template = ERB.new(IO.read("#{RAILS_ROOT}/app/views/sitemap/index.html.erb"))
f.puts(template.result(binding))

This code worked in 2.3, but breaks in Rails 3 as url_for does not access @controller anymore, but controller. (I think that's why.)

undefined local variable or method `controller' for #<Object:0x3794c>
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/helpers/url_helper.rb:31:in `url_options'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_dispatch/routing/url_for.rb:132:in `url_for'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/helpers/url_helper.rb:99:in `url_for'
(erb):5
/Users/me/Documents/Projects/zvg2/lib/tasks/zvg.rake:452

I also tried creating an ActionView to do it like that:

av = ActionView::Base.new(Rails::Application::Configuration.new(Rails.root).view_path, {
  # my assigns
}, @controller)
av.class_eval do
  include ApplicationHelper
end
f.puts(av.render(:template => "sitemap/index.html"))

But the problem seems to be the same, although ActionView::Base.new takes my controller.

undefined local variable or method `controller' for nil:NilClass
/opt/local/lib/ruby/gems/1.8/gems/activesupport-3.0.1/lib/active_support/whiny_nil.rb:48:in `method_missing'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/helpers/url_helper.rb:31:in `url_options'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_dispatch/routing/url_for.rb:132:in `url_for'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/helpers/url_helper.rb:99:in `url_for'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_dispatch/routing/url_for.rb:132:in `url_for'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/helpers/url_helper.rb:99:in `url_for'
/Users/me/Documents/Projects/zvg2/app/views/sitemap/index.html.erb:5:in `_app_views_sitemap_index_html_erb__757224102_30745030_0'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/template.rb:135:in `send'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/template.rb:135:in `render'
/opt/local/lib/ruby/gems/1.8/gems/activesupport-3.0.1/lib/active_support/notifications.rb:54:in `instrument'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/template.rb:127:in `render'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/render/rendering.rb:59:in `_render_template'
/opt/local/lib/ruby/gems/1.8/gems/activesupport-3.0.1/lib/active_support/notifications.rb:52:in `instrument'
/opt/local/lib/ruby/gems/1.8/gems/activesupport-3.0.1/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
/opt/local/lib/ruby/gems/1.8/gems/activesupport-3.0.1/lib/active_support/notifications.rb:52:in `instrument'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/render/rendering.rb:56:in `_render_template'
/opt/local/lib/ruby/gems/1.8/gems/actionpack-3.0.1/lib/action_view/render/rendering.rb:26:in `render'
/Users/me/Documents/Projects/zvg2/lib/tasks/zvg.rake:450

What's the best practice for rendering a template with rake that uses url_for and link_to? I bet as Rails just got more modular, there should be an easy way for just this?

Thanks in advance! Jan

Answer 1

One of the approaches works when I include Rails.application.routes.url_helpers instead of ActionView::Helpers::UrlHelper. This works for now:

include Rails.application.routes.url_helpers # brings ActionDispatch::Routing::UrlFor
include ActionView::Helpers::TagHelper

av = ActionView::Base.new(Rails.root.join('app', 'views'))
av.assign({
  :regions => @regions,
  :courts_by_region => @courts_by_region,
  :cities_by_region => @cities_by_region,
  :districts_by_region => @districts_by_region
})
f = File.new(file_name, 'w')
f.puts(av.render(:template => "sitemap/index.html"))
f.close

Hope this helps others. If there is a better solution, I'd be interested.

Also, how do I automatically get a hash of assigns from binding?

Answer 2

I was successfull by doing something like this:

class Template < ActionView::Base
  include Rails.application.routes.url_helpers
  include ActionView::Helpers::TagHelper

  def default_url_options
    {host: 'yourhost.org'}
  end
end  

template = Template.new(Rails.root.join('app', 'views'))
template.assign(attendee: @attendee)
template.render(template: 'sitemap/index.html.erb')

Answer 3

This is what worked for me (Rails 3):

class TaskActionView < ActionView::Base
  include Rails.application.routes.url_helpers
  include ApplicationHelper

  def default_url_options
     {host: 'example.com'}
  end
end

def action_view
  controller = ActionController::Base.new
  controller.request = ActionDispatch::TestRequest.new
  TaskActionView.new(Rails.root.join('app', 'views'), {}, controller)
end

action_view.render(:template =>"path/to/template")

This successfully included my application helper, tag helpers, and url helpers. You'll want to put your application/environments host properly into the default_url_options hash.