Carrierwave загрузка файлов - неопределенный метод `удаление» для ноля: NilClass

Question

Я пытаюсь загрузить файл в форме, используя carrierwave драгоценного камня, но я получаю следующее сообщение об ошибке:

NoMethodError в DashboardController # создание: неопределенный метод `delete 'for nil: NilClass

Что я делаю неправильно?

Параметры запроса:

{"utf8"=>"✓", 
"authenticity_token"=>"bv+3HGSl2/sDUi/aXqDw+b3XWgBM+cvXUrAQTZxWHeA=", 
"song"=>{"user_id"=>"", 
"title"=>"2", 
"artist"=>"3", 
"album"=>"4", 
"musicfile"=>#<ActionDispatch::Http::UploadedFile:0x00000001bb5bb0 @tempfile=#<Tempfile:/tmp/RackMultipart20131209-11818-jf368b>, 
@original_filename="dg.mp3", 
@content_type="audio/mp3", 
@headers="Content-Disposition: form-data; name=\"song[musicfile]\"; filename=\"dg.mp3\"\r\nContent-Type: audio/mp3\r\n">}, 
"commit"=>"Upload"} 

методы контроллера:

def new 
     @song = Song.new 
    end 
    def create 
     @song=Song.new(params[:song]) 
     @song.save 
     uploader = MusicfileUploader.new 
     uploader.store!(params[:song][:musicfile]) 

     #redirect_to dashboard_index_path 
    end 

Или, если вам нужно все:

https://github.com/cristi92b/GS2

EDIT:

выход терминального сервера:

Started GET "/dashboard/new" for 127.0.0.1 at 2013-12-09 17:54:15 +0200 
Processing by DashboardController#new as HTML 
    Rendered dashboard/_form.html.erb (112.5ms) 
    Rendered dashboard/new.html.erb within layouts/application (122.0ms) 
Completed 200 OK in 131ms (Views: 128.2ms | ActiveRecord: 0.5ms) 

Started POST "/dashboard" for 127.0.0.1 at 2013-12-09 17:54:44 +0200 
Processing by DashboardController#create as HTML 
    Parameters: {"utf8"=>"✓", "authenticity_token"=>"IfQNLZ8OuXjkowgj35C4BbC6nbusB+anhvNiL2SlEQY=", "song"=>{"user_id"=>"", "title"=>"1", "artist"=>"2", "album"=>"3", "musicfile"=>#<ActionDispatch::Http::UploadedFile:0x00000003086080 @tempfile=#<Tempfile:/tmp/RackMultipart20131209-2805-1jvt87a>, @original_filename="dg.mp3", @content_type="audio/mp3", @headers="Content-Disposition: form-data; name=\"song[musicfile]\"; filename=\"dg.mp3\"\r\nContent-Type: audio/mp3\r\n">}, "commit"=>"Upload"} 
Completed 500 Internal Server Error in 1ms 

NoMethodError (undefined method `delete' for nil:NilClass): 
    app/controllers/dashboard_controller.rb:12:in `create' 


    Rendered /home/cristi/.gem/ruby/2.0.0/gems/actionpack-4.0.2/lib/action_dispatch/middleware/templates/rescues/_source.erb (0.8ms) 
    Rendered /home/cristi/.gem/ruby/2.0.0/gems/actionpack-4.0.2/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.4ms) 
    Rendered /home/cristi/.gem/ruby/2.0.0/gems/actionpack-4.0.2/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (1.3ms) 
    Rendered /home/cristi/.gem/ruby/2.0.0/gems/actionpack-4.0.2/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (15.2ms) 

веб-страница "Полный след":

activerecord (4.0.2) lib/active_record/attribute_methods/write.rb:35:in `write_attribute' 
activerecord (4.0.2) lib/active_record/attribute_methods/dirty.rb:70:in `write_attribute' 
activerecord (4.0.2) lib/active_record/attribute_methods/write.rb:21:in `__temp__57375627f59646=' 
activemodel (4.0.2) lib/active_model/model.rb:80:in `public_send' 
activemodel (4.0.2) lib/active_model/model.rb:80:in `block in initialize' 
activemodel (4.0.2) lib/active_model/model.rb:79:in `each' 
activemodel (4.0.2) lib/active_model/model.rb:79:in `initialize' 
activerecord (4.0.2) lib/active_record/inheritance.rb:27:in `new' 
activerecord (4.0.2) lib/active_record/inheritance.rb:27:in `new' 
app/controllers/dashboard_controller.rb:12:in `create' 
actionpack (4.0.2) lib/action_controller/metal/implicit_render.rb:4:in `send_action' 
actionpack (4.0.2) lib/abstract_controller/base.rb:189:in `process_action' 
actionpack (4.0.2) lib/action_controller/metal/rendering.rb:10:in `process_action' 
actionpack (4.0.2) lib/abstract_controller/callbacks.rb:18:in `block in process_action' 
activesupport (4.0.2) lib/active_support/callbacks.rb:403:in `_run__1534113615882314291__process_action__callbacks' 
activesupport (4.0.2) lib/active_support/callbacks.rb:80:in `run_callbacks' 
actionpack (4.0.2) lib/abstract_controller/callbacks.rb:17:in `process_action' 
actionpack (4.0.2) lib/action_controller/metal/rescue.rb:29:in `process_action' 
actionpack (4.0.2) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action' 
activesupport (4.0.2) lib/active_support/notifications.rb:159:in `block in instrument' 
activesupport (4.0.2) lib/active_support/notifications/instrumenter.rb:20:in `instrument' 
activesupport (4.0.2) lib/active_support/notifications.rb:159:in `instrument' 
actionpack (4.0.2) lib/action_controller/metal/instrumentation.rb:30:in `process_action' 
actionpack (4.0.2) lib/action_controller/metal/params_wrapper.rb:245:in `process_action' 
activerecord (4.0.2) lib/active_record/railties/controller_runtime.rb:18:in `process_action' 
actionpack (4.0.2) lib/abstract_controller/base.rb:136:in `process' 
actionpack (4.0.2) lib/abstract_controller/rendering.rb:44:in `process' 
actionpack (4.0.2) lib/action_controller/metal.rb:195:in `dispatch' 
actionpack (4.0.2) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch' 
actionpack (4.0.2) lib/action_controller/metal.rb:231:in `block in action' 
actionpack (4.0.2) lib/action_dispatch/routing/route_set.rb:80:in `call' 
actionpack (4.0.2) lib/action_dispatch/routing/route_set.rb:80:in `dispatch' 
actionpack (4.0.2) lib/action_dispatch/routing/route_set.rb:48:in `call' 
actionpack (4.0.2) lib/action_dispatch/journey/router.rb:71:in `block in call' 
actionpack (4.0.2) lib/action_dispatch/journey/router.rb:59:in `each' 
actionpack (4.0.2) lib/action_dispatch/journey/router.rb:59:in `call' 
actionpack (4.0.2) lib/action_dispatch/routing/route_set.rb:680:in `call' 
warden (1.2.3) lib/warden/manager.rb:35:in `block in call' 
warden (1.2.3) lib/warden/manager.rb:34:in `catch' 
warden (1.2.3) lib/warden/manager.rb:34:in `call' 
rack (1.5.2) lib/rack/etag.rb:23:in `call' 
rack (1.5.2) lib/rack/conditionalget.rb:35:in `call' 
rack (1.5.2) lib/rack/head.rb:11:in `call' 
actionpack (4.0.2) lib/action_dispatch/middleware/params_parser.rb:27:in `call' 
actionpack (4.0.2) lib/action_dispatch/middleware/flash.rb:241:in `call' 
rack (1.5.2) lib/rack/session/abstract/id.rb:225:in `context' 
rack (1.5.2) lib/rack/session/abstract/id.rb:220:in `call' 
actionpack (4.0.2) lib/action_dispatch/middleware/cookies.rb:486:in `call' 
activerecord (4.0.2) lib/active_record/query_cache.rb:36:in `call' 
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in `call' 
activerecord (4.0.2) lib/active_record/migration.rb:369:in `call' 
actionpack (4.0.2) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call' 
activesupport (4.0.2) lib/active_support/callbacks.rb:373:in `_run__992470349095990657__call__callbacks' 
activesupport (4.0.2) lib/active_support/callbacks.rb:80:in `run_callbacks' 
actionpack (4.0.2) lib/action_dispatch/middleware/callbacks.rb:27:in `call' 
actionpack (4.0.2) lib/action_dispatch/middleware/reloader.rb:64:in `call' 
actionpack (4.0.2) lib/action_dispatch/middleware/remote_ip.rb:76:in `call' 
actionpack (4.0.2) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call' 
actionpack (4.0.2) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call' 
railties (4.0.2) lib/rails/rack/logger.rb:38:in `call_app' 
railties (4.0.2) lib/rails/rack/logger.rb:20:in `block in call' 
activesupport (4.0.2) lib/active_support/tagged_logging.rb:67:in `block in tagged' 
activesupport (4.0.2) lib/active_support/tagged_logging.rb:25:in `tagged' 
activesupport (4.0.2) lib/active_support/tagged_logging.rb:67:in `tagged' 
railties (4.0.2) lib/rails/rack/logger.rb:20:in `call' 
actionpack (4.0.2) lib/action_dispatch/middleware/request_id.rb:21:in `call' 
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call' 
rack (1.5.2) lib/rack/runtime.rb:17:in `call' 
activesupport (4.0.2) lib/active_support/cache/strategy/local_cache.rb:83:in `call' 
rack (1.5.2) lib/rack/lock.rb:17:in `call' 
actionpack (4.0.2) lib/action_dispatch/middleware/static.rb:64:in `call' 
rack (1.5.2) lib/rack/sendfile.rb:112:in `call' 
railties (4.0.2) lib/rails/engine.rb:511:in `call' 
railties (4.0.2) lib/rails/application.rb:97:in `call' 
rack (1.5.2) lib/rack/lock.rb:17:in `call' 
rack (1.5.2) lib/rack/content_length.rb:14:in `call' 
rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service' 
/usr/lib64/ruby/2.0.0/webrick/httpserver.rb:138:in `service' 
/usr/lib64/ruby/2.0.0/webrick/httpserver.rb:94:in `run' 
/usr/lib64/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread' 

Answer 1

Ошибка вы получаете из-за @attributes_cache быть nil внутри ActiveRecord. Если вы Google «@attributes_cache nil», вы найдете несколько вопросов об этом, но никаких ответов. Я понимаю, что это не очень важный ответ и, вероятно, вам действительно не поможет, но я думал, что эта информация принадлежала где-то, кроме комментария . Будем надеяться, что кто-то может построить на нем