How to render Rails 3.0 views within rake tasks (with url helpers!)

render.rake

# How to render rails 3.0 views within rake tasks.
#
# Description: An example of how to render a view within a rake task, 
# complete with instance variables, application & url helpers and I18n.
#
# License: X11 license
#
# Copyright (c) 2010 Kim Burgestrand <http://burgestrand.se/>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

# Creates an instance of ActionView with:
#
# @param Hash url_options (see default_url_options)
# @param [ActionView::LookupContext, nil]
# @param [Hash<:sym => val>, nil] assigns
# @param [#request & #config, nil] controller
# @param [Array<Symbol>, nil] formats
# @return ActionView::Base
def view(url_options = {}, *view_args)
  view_args[0] ||= ActionController::Base.view_paths
  view_args[1] ||= {}
  
  view = ActionView::Base.new(*view_args)
  routes = Rails::Application.routes
  routes.default_url_options = {:host => 'localhost'}.merge(url_options)

  view.class_eval do
    include ApplicationHelper
    include routes.url_helpers
  end

  assigns = instance_variables.inject(Hash.new) do |hash, name|
    hash.merge name[1..-1] => instance_variable_get(name)
  end
  view.assign assigns
  
  view
end

## Example
# task :render => :environment do
#   @song = Song.first
#   puts view.render :file => "songs/show"
# end