Missing default_host_options in rails model

gistfile1.rb

# application_controller.rb
before_filter :default_hosts

# set dynamically to always correct paths and urls (dev, stage, testing)
def default_hosts
  ActionController::Base.default_url_options[:host] = request.host_with_port
  ActionMailer::Base.default_url_options[:host] = request.host_with_port
end


# my_model.rb
class MyModel < AR::Base
    
  def return_url
    Rails.application.routes.url_helpers.verify_paypal_payment_notifications_url(order_id)
  end
  
end


# this results in
# Missing host to link to! Please provide :host parameter or set default_url_options[:host]

# so what's the best practise to get this error down?

I think if you are calling a method the preferred solution is to pass to the URL from the view, e.g.

    # app/models/foo.rb
    def some_fancy_method(url)
      # do something with url and return result
    end

    # app/views/foo.erb.html
    @foo.some_fancy_method(content_url(foo.content))