Rails 3.1 asset pipeline outside view

I am trying to set CarrierWave's default url inside of the CarrierWave uploader. To do this, I would like to use the asset pipeline to do the following in uploaders/image_uploader.rb: def default_url image_path('question_ma开发者_Python百科rk.png') end

But it fails because: undefined methodimage_path' for :ImageUploader`

Then I tried to add include ActionView::Helpers::AssetTagHelper to uploaders/image_uploader.rb but got this error: undefined local variable or methodconfig' for :ImageUploader`

Any idea how I can get the image_path helper to work outside the view?

I asked a similar question here and concluded there is no way to get any *_path or *_url helpers working in models. I knew that it definitely shouldn't be done (violating MVC and so forth) but it seems it cannot be done at all...

My problem was setting the default_url for a Paperclip attachment and I ended up setting it to the path I would give to image_tag (simply 'image.png' if image.png is located in app/assets/images or public/images) and then using image_path when accessing it. Would that work for you as well?

Not sure exactly what I was trying to do here, ended up working around it but in case anyone comes here wanting to add the _path or _url helpers in their model, do this:

class Post < ActiveRecord :: Base
  include Rails.application.routes.url_helpers

  # This is so you can use _url params
  # you'll need to define the host in your config for it to work though
  default_url_options[:host] = Rails.configuration.host

  # ...

end

I had a similar problem and I resolved it by doing the following in Rails 3.2.

I declared the following module:

module MyApp::AssetHelper
  def config
    @config ||= ActionController::Base.config
    @config.asset_host = 'http://whereveryouhostyour.assets' #not needed if you have this defined in your environment file
    @config
  end

  def controller
    ActionController::Base
  end
end

I included the following helpers into the model where I wanted to use the asset_tag helpers

include Sprockets::Helpers::RailsHelper
include MyApp::AssetHelper

This allowed me to call the asset_tag helpers where I needed it.