我是Ruby on Rails的新手，并尝试按照本指南创建一个相对简单的Web应用程序：http://www.sitepoint.com/youtube-rails/。我已经到了所有代码都已到位但仍然获得NoMethodError in VideosController#create：
undefined method `uid=' for #<Video:0x007fb066c41d28>
应用程序/控制器/ videos_controller.rb
class VideosController < ApplicationController
def index
@videos = Video.order('created_at DESC')
end
def new
@video = Video.new
end
def create
@video = Video.new(params[:video])
if @video.save
flash[:success] = 'Video added!'
redirect_to root_url
else
render 'new'
end
end
end
应用程序/模型/ video.rb
class Video < ActiveRecord::Base
attr_accessible :link
YT_LINK_FORMAT = /^.*(youtu.be\/|v\/|u\/\w\/|embed\/|watch\?v=|\&v=)([^#\&\?]*).*/i
validates :link, presence: true, format: YT_LINK_FORMAT
before_create -> do
uid = link.match(YT_LINK_FORMAT)
self.uid = uid[2] if uid && uid[2]
if self.uid.to_s.length != 11
self.errors.add(:link, 'is invalid.')
false
elsif Video.where(uid: self.uid).any?
self.errors.add(:link, 'is not unique.')
false
else
get_additional_info
end
end
private
def get_additional_info
begin
client = YouTubeIt::OAuth2Client.new(dev_key: '<my_dev_key>')
video = client.video_by(uid)
self.title = video.title
self.duration = parse_duration(video.duration)
self.author = video.author.name
self.likes = video.rating.likes
self.dislikes = video.rating.dislikes
rescue
self.title = '' ; self.duration = '00.00.00' ; self.author = '' ; self.likes = 0 ; self.dislikes = 0
end
end
def parse_duration(d)
hr = (d / 3600).floor
min = ((d - (hr * 3600)) / 60).floor
sec = (d - (hr * 3600) - (min * 60)).floor
hr = '0' + hr.to_s if hr.to_i < 10
min = '0' + min.to_s if min.to_i < 10
sec = '0' + sec.to_s if sec.to_i < 10
hr.to_s + ':' + min.to_s + ':' + sec.to_s
end
end
完整追踪
activemodel (3.2.17) lib/active_model/attribute_methods.rb:407:in `method_missing'
activerecord (3.2.17) lib/active_record/attribute_methods.rb:149:in `method_missing'
app/models/video.rb:10:in `block in <class:Video>'
activesupport (3.2.17) lib/active_support/callbacks.rb:407:in `_run__3695319422649908747__create__1619689881822406221__callbacks'
activesupport (3.2.17) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.17) lib/active_support/callbacks.rb:385:in `_run_create_callbacks'
activesupport (3.2.17) lib/active_support/callbacks.rb:81:in `run_callbacks'
activerecord (3.2.17) lib/active_record/callbacks.rb:268:in `create'
activerecord (3.2.17) lib/active_record/persistence.rb:348:in `create_or_update'
activerecord (3.2.17) lib/active_record/callbacks.rb:264:in `block in create_or_update'
activesupport (3.2.17) lib/active_support/callbacks.rb:403:in `_run__3695319422649908747__save__1619689881822406221__callbacks'
activesupport (3.2.17) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.17) lib/active_support/callbacks.rb:385:in `_run_save_callbacks'
activesupport (3.2.17) lib/active_support/callbacks.rb:81:in `run_callbacks'
activerecord (3.2.17) lib/active_record/callbacks.rb:264:in `create_or_update'
activerecord (3.2.17) lib/active_record/persistence.rb:84:in `save'
activerecord (3.2.17) lib/active_record/validations.rb:50:in `save'
activerecord (3.2.17) lib/active_record/attribute_methods/dirty.rb:22:in `save'
activerecord (3.2.17) lib/active_record/transactions.rb:259:in `block (2 levels) in save'
activerecord (3.2.17) lib/active_record/transactions.rb:313:in `block in with_transaction_returning_status'
activerecord (3.2.17) lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction'
activerecord (3.2.17) lib/active_record/transactions.rb:208:in `transaction'
activerecord (3.2.17) lib/active_record/transactions.rb:311:in `with_transaction_returning_status'
activerecord (3.2.17) lib/active_record/transactions.rb:259:in `block in save'
activerecord (3.2.17) lib/active_record/transactions.rb:270:in `rollback_active_record_state!'
activerecord (3.2.17) lib/active_record/transactions.rb:258:in `save'
app/controllers/videos_controller.rb:12:in `create'
actionpack (3.2.17) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.2.17) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.2.17) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.2.17) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.2.17) lib/active_support/callbacks.rb:414:in `_run__333554687839828986__process_action__1999722818964258122__callbacks'
activesupport (3.2.17) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.17) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
activesupport (3.2.17) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.17) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.2.17) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (3.2.17) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.2.17) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.17) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.17) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.17) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.2.17) lib/action_controller/metal/params_wrapper.rb:207:in `process_action'
activerecord (3.2.17) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.2.17) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.2.17) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.2.17) lib/action_controller/metal.rb:203:in `dispatch'
actionpack (3.2.17) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.2.17) lib/action_controller/metal.rb:246:in `block in action'
actionpack (3.2.17) lib/action_dispatch/routing/route_set.rb:73:in `call'
actionpack (3.2.17) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
actionpack (3.2.17) lib/action_dispatch/routing/route_set.rb:36:in `call'
journey (1.0.4) lib/journey/router.rb:68:in `block in call'
journey (1.0.4) lib/journey/router.rb:56:in `each'
journey (1.0.4) lib/journey/router.rb:56:in `call'
actionpack (3.2.17) lib/action_dispatch/routing/route_set.rb:608:in `call'
actionpack (3.2.17) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.4.5) lib/rack/etag.rb:23:in `call'
rack (1.4.5) lib/rack/conditionalget.rb:35:in `call'
actionpack (3.2.17) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.2.17) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.2.17) lib/action_dispatch/middleware/flash.rb:242:in `call'
rack (1.4.5) lib/rack/session/abstract/id.rb:210:in `context'
rack (1.4.5) lib/rack/session/abstract/id.rb:205:in `call'
actionpack (3.2.17) lib/action_dispatch/middleware/cookies.rb:341:in `call'
activerecord (3.2.17) lib/active_record/query_cache.rb:64:in `call'
activerecord (3.2.17) lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in `call'
actionpack (3.2.17) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (3.2.17) lib/active_support/callbacks.rb:405:in `_run__469011070482330715__call__1619689881822406221__callbacks'
activesupport (3.2.17) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.17) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
activesupport (3.2.17) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.17) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (3.2.17) lib/action_dispatch/middleware/reloader.rb:65:in `call'
actionpack (3.2.17) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
actionpack (3.2.17) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
actionpack (3.2.17) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
railties (3.2.17) lib/rails/rack/logger.rb:32:in `call_app'
railties (3.2.17) lib/rails/rack/logger.rb:16:in `block in call'
activesupport (3.2.17) lib/active_support/tagged_logging.rb:22:in `tagged'
railties (3.2.17) lib/rails/rack/logger.rb:16:in `call'
actionpack (3.2.17) lib/action_dispatch/middleware/request_id.rb:22:in `call'
rack (1.4.5) lib/rack/methodoverride.rb:21:in `call'
rack (1.4.5) lib/rack/runtime.rb:17:in `call'
activesupport (3.2.17) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.5) lib/rack/lock.rb:15:in `call'
actionpack (3.2.17) lib/action_dispatch/middleware/static.rb:63:in `call'
railties (3.2.17) lib/rails/engine.rb:484:in `call'
railties (3.2.17) lib/rails/application.rb:231:in `call'
rack (1.4.5) lib/rack/content_length.rb:14:in `call'
railties (3.2.17) lib/rails/rack/log_tailer.rb:17:in `call'
rack (1.4.5) lib/rack/handler/webrick.rb:59:in `service'
/Users/<User_Name>/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/webrick/httpserver.rb:111:in `service'
/Users/Kappe/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/webrick/httpserver.rb:70:in `run'
/Users/Kappe/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/webrick/server.rb:183:in `block in start_thread'
我希望我已经提供了足够的信息。我认为在video.rb中发生了一些事情，其中设置了uid和self.uid，但我没有足够的知识来解决这个问题。你能帮帮我吗？提前谢谢！
答案 0 :(得分：0)
未定义的方法`uid =＆＃39;对于＃
错误是因为 uid 表中没有 videos 属性。
您应该通过迁移添加该属性
AddUidToVideo uid:string
这将创建一个迁移文件，用于向该表添加uid列
做rake db:migrate