expire_action producing `can't convert Symbol into Integer` error

download_type_sweeper.rb

class DownloadTypeSweeper < ActionController::Caching::Sweeper
  observe DownloadType
  
  def after_save(download_type)
    expire_cache_for download_type
  end
  
  def before_destroy(download_type)
    expire_cache_for download_type
  end
  
  private
    
    def expire_cache_for(download_type)
      # Expire page caches
      # When the list order changes, expire all product support pages
      @products = Product.all
      @products.each do |product|
        expire_action support_product_line_product_url(product.product_line_id, product)
      end
    end
end

download_types_controller.rb

module Admin
  class DownloadTypesController < BaseController
  
    cache_sweeper :download_type_sweeper, :only => [:create, :update, :destroy]
  
    # GET /download_types
    def index
      @download_types = DownloadType.order('position ASC')
    end

    # GET /:locale/admin/download_types/new
    def new
      @download_type = DownloadType.new
    end

    # GET /:locale/admin/download_types/1/edit
    def edit
      @download_type = DownloadType.find(params[:id])
    end
  
    # POST /:locale/admin/download_types
    def create
      @download_type = DownloadType.new(params[:download_type])
    
      if @download_type.save
        flash[:notice] = "<em>#{@download_type.name}</em> was successfully created."
        redirect_to admin_download_types_path
      else
        render :action => 'new'
      end
    end
  
    # PUT /:locale/admin/download_types/1
    def update
      @download_type = DownloadType.find(params[:id])
    
      if @download_type.update_attributes(params[:download_type])
        redirect_to admin_download_types_path
      else
        render :action => 'edit'
      end
    end
  
    # PUT /:locale/admin/download_types/sort
    def sort
      params[:download_type].each_with_index do |id, index|
        DownloadType.update_all({ position: index + 1 }, { id: id })
      end
    
      # Expire page caches
      @products = Product.all
      @products.each do |product|
        expire_action support_product_line_product_path(product.product_line_id, product)
      end
    
      render nothing: true
    end
  
    # DELETE /:locale/admin/download_types/1
    def destroy
      @download_type = DownloadType.find(params[:id])
      @download_type.destroy
      redirect_to admin_download_types_path
    end

  end
end

gistfile1.txt

actionpack (3.1.1) lib/action_controller/caching/actions.rb:119:in `[]'
actionpack (3.1.1) lib/action_controller/caching/actions.rb:119:in `expire_action'
actionpack (3.1.1) lib/action_controller/caching/sweeping.rb:92:in `method_missing'
app/sweepers/download_type_sweeper.rb:19:in `block in expire_cache_for'
app/sweepers/download_type_sweeper.rb:18:in `each'
app/sweepers/download_type_sweeper.rb:18:in `expire_cache_for'
app/sweepers/download_type_sweeper.rb:5:in `after_save'
activemodel (3.1.1) lib/active_model/observing.rb:232:in `update'
activerecord (3.1.1) lib/active_record/observer.rb:114:in `block (2 levels) in define_callbacks'
activesupport (3.1.1) lib/active_support/callbacks.rb:401:in `_run_save_callbacks'
activesupport (3.1.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
activerecord (3.1.1) lib/active_record/callbacks.rb:264:in `create_or_update'
activerecord (3.1.1) lib/active_record/persistence.rb:37:in `save'
activerecord (3.1.1) lib/active_record/validations.rb:50:in `save'
activerecord (3.1.1) lib/active_record/attribute_methods/dirty.rb:22:in `save'
activerecord (3.1.1) lib/active_record/transactions.rb:241:in `block (2 levels) in save'
activerecord (3.1.1) lib/active_record/transactions.rb:295:in `block in with_transaction_returning_status'
activerecord (3.1.1) lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction'
activerecord (3.1.1) lib/active_record/transactions.rb:208:in `transaction'
activerecord (3.1.1) lib/active_record/transactions.rb:293:in `with_transaction_returning_status'
activerecord (3.1.1) lib/active_record/transactions.rb:241:in `block in save'
activerecord (3.1.1) lib/active_record/transactions.rb:252:in `rollback_active_record_state!'
activerecord (3.1.1) lib/active_record/transactions.rb:240:in `save'
app/controllers/admin/download_types_controller.rb:25:in `create'
actionpack (3.1.1) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.1.1) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.1.1) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.1.1) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.1.1) lib/active_support/callbacks.rb:471:in `block in _run__57107674272883730__process_action__376869027667169981__callbacks'
activesupport (3.1.1) lib/active_support/callbacks.rb:207:in `block in _conditional_callback_around_717'
activesupport (3.1.1) lib/active_support/callbacks.rb:318:in `around'
activesupport (3.1.1) lib/active_support/callbacks.rb:302:in `_callback_around_128'
activesupport (3.1.1) lib/active_support/callbacks.rb:206:in `_conditional_callback_around_717'
activesupport (3.1.1) lib/active_support/callbacks.rb:470:in `_run__57107674272883730__process_action__376869027667169981__callbacks'
activesupport (3.1.1) lib/active_support/callbacks.rb:386:in `_run_process_action_callbacks'
activesupport (3.1.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.1.1) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.1.1) lib/action_controller/metal/rescue.rb:17:in `process_action'
actionpack (3.1.1) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.1.1) lib/active_support/notifications.rb:53:in `block in instrument'
activesupport (3.1.1) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (3.1.1) lib/active_support/notifications.rb:53:in `instrument'
actionpack (3.1.1) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.1.1) lib/action_controller/metal/params_wrapper.rb:201:in `process_action'
activerecord (3.1.1) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.1.1) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.1.1) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.1.1) lib/action_controller/metal.rb:193:in `dispatch'
actionpack (3.1.1) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.1.1) lib/action_controller/metal.rb:236:in `block in action'
actionpack (3.1.1) lib/action_dispatch/routing/route_set.rb:65:in `call'
actionpack (3.1.1) lib/action_dispatch/routing/route_set.rb:65:in `dispatch'
actionpack (3.1.1) lib/action_dispatch/routing/route_set.rb:29:in `call'
rack-mount (0.8.3) lib/rack/mount/route_set.rb:152:in `block in call'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:96:in `block in recognize'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:173:in `optimized_each'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:95:in `recognize'
rack-mount (0.8.3) lib/rack/mount/route_set.rb:141:in `call'
actionpack (3.1.1) lib/action_dispatch/routing/route_set.rb:532:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.3.5) lib/rack/etag.rb:23:in `call'
rack (1.3.5) lib/rack/conditionalget.rb:35:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/flash.rb:243:in `call'
rack (1.3.5) lib/rack/session/abstract/id.rb:195:in `context'
rack (1.3.5) lib/rack/session/abstract/id.rb:190:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/cookies.rb:331:in `call'
activerecord (3.1.1) lib/active_record/query_cache.rb:62:in `call'
activerecord (3.1.1) lib/active_record/connection_adapters/abstract/connection_pool.rb:477:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (3.1.1) lib/active_support/callbacks.rb:392:in `_run_call_callbacks'
activesupport (3.1.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.1.1) lib/action_dispatch/middleware/callbacks.rb:28:in `call'
rack (1.3.5) lib/rack/sendfile.rb:101:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/remote_ip.rb:48:in `call'
actionpack (3.1.1) lib/action_dispatch/middleware/show_exceptions.rb:47:in `call'
railties (3.1.1) lib/rails/rack/logger.rb:13:in `call'
rack (1.3.5) lib/rack/methodoverride.rb:24:in `call'
rack (1.3.5) lib/rack/runtime.rb:17:in `call'
activesupport (3.1.1) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.3.5) lib/rack/lock.rb:15:in `call'
rack-cache (1.1) lib/rack/cache/context.rb:132:in `forward'
rack-cache (1.1) lib/rack/cache/context.rb:139:in `pass'
rack-cache (1.1) lib/rack/cache/context.rb:151:in `invalidate'
rack-cache (1.1) lib/rack/cache/context.rb:70:in `call!'
rack-cache (1.1) lib/rack/cache/context.rb:50:in `call'
railties (3.1.1) lib/rails/engine.rb:456:in `call'
railties (3.1.1) lib/rails/railtie/configurable.rb:30:in `method_missing'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/rack/request_handler.rb:96:in `process_request'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_request_handler.rb:513:in `accept_and_process_next_request'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_request_handler.rb:274:in `main_loop'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/rack/application_spawner.rb:205:in `start_request_handler'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/rack/application_spawner.rb:170:in `block in handle_spawn_application'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/utils.rb:479:in `safe_fork'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/rack/application_spawner.rb:165:in `handle_spawn_application'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server.rb:357:in `server_main_loop'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server.rb:206:in `start_synchronously'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server.rb:180:in `start'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/rack/application_spawner.rb:128:in `start'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/spawn_manager.rb:253:in `block (2 levels) in spawn_rack_application'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server_collection.rb:132:in `lookup_or_add'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/spawn_manager.rb:246:in `block in spawn_rack_application'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server_collection.rb:82:in `block in synchronize'
<internal:prelude>:10:in `synchronize'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server_collection.rb:79:in `synchronize'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/spawn_manager.rb:244:in `spawn_rack_application'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/spawn_manager.rb:137:in `spawn_application'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/spawn_manager.rb:275:in `handle_spawn_application'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server.rb:357:in `server_main_loop'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/lib/phusion_passenger/abstract_server.rb:206:in `start_synchronously'
/usr/local/rvm/gems/ruby-1.9.2-p290/gems/passenger-3.0.9/helper-scripts/passenger-spawn-server:99:in `<main>'

products_controller.rb

module Support
  class ProductsController < BaseController
    before_filter :get_product_line
    caches_action :show, :layout => false
  
    def show
      @product = @product_line.products.find(params[:id])
    
      #get the downloads for this product
      @downloads = Download.get_by_product(@product.id)
    end
  
    private
  
      def get_product_line
        @product_line = ProductLine.find(params[:product_line_id])
      end

  end
end