Using Erubis 2.6.2 with Rails 2.2.2 is incompatible?

Question

Supposedly installing erubis is as simple as:

gem install erubis

# And in environment.rb:
require 'erubis/helpers/rails_helper'

But I haven't found this to be so. Note that there are no evident errors in my code; it runs just fine and dandy with ERB.

1. Where do I put this line? Directly after the boot.rb inclusion it fails to start the server, and at the end of the file I get an unexpected nil object error (nil.controller). Where is best?
2. Are there known conflicts with the given versions?
3. Are there any workarounds I can utilize to get erubis functioning?

Answer 1

1. Either put it on the bottom or environment.rb, or put it in an initializer (config/initializers/anything.rb). When you put it before the Rails::Initializer block, the rails environment hasn't fully loaded yet, and erubis/helpers/rails_helpers seems to assume a fully loaded Rails environment.
2. I have never used erubis, so I can't answer that.
3. Workarounds? See #1, I guess.

Answer 2

Apparently this is broken:

http://kleinptr.wordpress.com/2009/02/04/erubis-and-rails-222/

and they're working on a fix:

http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/328613

Answer 3

The latest Erubis (2.6.4) and Rails 2.2 (and 2.3) are still not compatible. The main issue is that the generated ruby code from Erubis uses "_buf" as the buffer variable and Rails 2.2 and 2.3 require "@output_buffer" to be used.

The reason for "@output_buffer" to be used is that ActionView helpers like CaptureHelper are designed around "@output_buffer" being the primary buffer in the generated code.

I have created a gem called elkinsware-erubis_rails_helper that fixes these issues and allows Erubis and Rails 2.3 (for sure but it should work for 2.2).

In your environment.rb file add:

 config.gem 'erubis' , :version => '2.6.4'
 config.gem 'elkinsware-erubis_rails_helper', :lib => 'erubis_rails_helper', :source => 'http://gems.github.com'

And then you can add a config/initializers/erubis_config.rb where you can adjust the Erubis/Rails options.

 #Erubis::Helpers::RailsHelper.engine_class = Erubis::Eruby # or Erubis::FastEruby
 #Erubis::Helpers::RailsHelper.init_properties = {}
 #Erubis::Helpers::RailsHelper.show_src = false
 #Erubis::Helpers::RailsHelper.preprocessing = true

The source is at http://github.com/elkinsware/erubis_rails_helper/tree/master

Let me know if you have any issues with the gem.