[英]How to access a deep nested objects in Ruby on Rails?
您好,我在访问嵌套太深的对象时遇到问题。 我希望你们中的一个可以帮助我或遇到同样的问题? 由于我的应用程序导航,我无法以更简单的方式重构嵌套对象,因为我总是需要使用根对象,例如“ Users”
这是我的路线文件:
resources :users do
resources :posts do
resources :comments
end
end
用户模型
class User < ActiveRecord::Base
has_many :posts
end
邮政模型
class Post < ActiveRecord::Base
belongs_to :user
has_many :comments
end
评论模型
class Comment < ActiveRecord::Base
belongs_to :post
end
现在,当我尝试访问用户的帖子时,一切正常。 它可以让我选择所有用户的帖子。
class PostsController < ApplicationController
before_filter :user
respond_to :html, :xml
def index
@posts = user.posts.all
respond_with(@posts)
end
protected
def user
@user ||= User.find(params[:user_id])
end
end
但是,当我尝试访问用户的帖子评论时,出现错误...我想选择与用户的帖子相关的所有评论。所以这就是我所做的。 我的评论控制器:
class CommentsController < ApplicationController
before_filter :user, :post
respond_to :html, :xml
def index
@comments = post.comments.all
respond_with(@comments)
end
protected
def user
@user ||= User.find(params[:user_id])
end
def post
@post ||= user.posts.find(params[:post_id])
end
end
例如,尝试访问时发生以下错误: http:// localhost:3000 / users / 1 / posts / 3 / comments /
NameError(未初始化的常量Post :: Comments):
app / controllers / comments_controller.rb:7:in'index'这是相关的路由列表。
user_post_comments_index GET /users/:user_id/posts/:post_id/comments(.:format) {:action=>"index", :controller=>"comments"}
POST /users/:user_id/posts/:post_id/comments(.:format) {:action=>"create", :controller=>"comments"}
new_user_post_comments GET /users/:user_id/posts/:post_id/comments/new(.:format) {:action=>"new", :controller=>"comments"}
edit_user_post_comments GET /users/:user_id/posts/:post_id/comments/:id/edit(.:format) {:action=>"edit", :controller=>"comments"}
user_post_comments GET /users/:user_id/posts/:post_id/comments/:id(.:format) {:action=>"show", :controller=>"comments"}
PUT /users/:user_id/posts/:post_id/comments/:id(.:format) {:action=>"update", :controller=>"comments"}
DELETE /users/:user_id/posts/:post_id/comments/:id(.:format) {:action=>"destroy", :controller=>"comments"}
user_posts GET /users/:user_id/posts(.:format) {:action=>"index", :controller=>"posts"}
POST /users/:user_id/posts(.:format) {:action=>"create", :controller=>"posts"}
new_user_post GET /users/:user_id/posts/new(.:format) {:action=>"new", :controller=>"posts"}
edit_user_post GET /users/:user_id/posts/:id/edit(.:format) {:action=>"edit", :controller=>"posts"}
user_post GET /users/:user_id/posts/:id(.:format) {:action=>"show", :controller=>"posts"}
不知道这是否可以帮助,但是我添加了一些调试消息。
activerecord (3.0.3) lib/active_record/base.rb:1199:in `compute_type'
activerecord (3.0.3) lib/active_record/reflection.rb:162:in `send'
activerecord (3.0.3) lib/active_record/reflection.rb:162:in `klass'
activerecord (3.0.3) lib/active_record/reflection.rb:198:in `quoted_table_name'
activerecord (3.0.3) lib/active_record/associations/has_many_association.rb:102:in `construct_sql'
activerecord (3.0.3) lib/active_record/associations/association_collection.rb:24:in `initialize'
activerecord (3.0.3) lib/active_record/associations/has_many_association.rb:11:in `initialize'
activerecord (3.0.3) lib/active_record/associations.rb:1492:in `new'
activerecord (3.0.3) lib/active_record/associations.rb:1492:in `comments'
actionpack (3.0.3) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.0.3) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.0.3) lib/abstract_controller/base.rb:151:in `process_action'
actionpack (3.0.3) lib/action_controller/metal/rendering.rb:11:in `process_action'
actionpack (3.0.3) lib/abstract_controller/callbacks.rb:18:in `process_action'
activesupport (3.0.3) lib/active_support/callbacks.rb:450:in `_run__677074153__process_action__199225275__callbacks'
activesupport (3.0.3) lib/active_support/callbacks.rb:409:in `send'
activesupport (3.0.3) lib/active_support/callbacks.rb:409:in `_run_process_action_callbacks'
activesupport (3.0.3) lib/active_support/callbacks.rb:93:in `send'
activesupport (3.0.3) lib/active_support/callbacks.rb:93:in `run_callbacks'
actionpack (3.0.3) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.0.3) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
仅用于调试:从索引操作中删除respond_with(@comments)
其实一切看起来都不错。
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