在模型中使用 default_scope，通过正确的 instanceID 进行过滤 [英] Using default_scope in a model, to filter by the correct instanceID

问题描述

我有两张桌子:

书籍(id、name、desc、instance_id)实例(id，域)

books (id, name, desc, instance_id) instances (id, domain)

用户应该只能看到记录中分配给他们的 instance_id 的数据...

A user should ONLY be able to see data that is assigned to their instance_id in records...

对于书籍、模型，为了实现这一点，我正在考虑使用默认范围.. 类似:

For the books, model, to accomplish this, I'm thinking about using a default scope.. Something like:

class Books < ActiveRecord::Base
    attr_accessible :name, :description
    belongs_to :user
    default_scope :order => 'books.created_at DESC'
        AND books.instance_id == current.user.instance_id 
end

对这个想法有什么想法吗?另外，如何为 Rails 3 编写倒数第二行?'AND books.instance_id == current.user.instance_id'

Any thoughts on that idea? Also how can I write that 2nd to last line for Rails 3? 'AND books.instance_id == current.user.instance_id'

谢谢

推荐答案

在模型中访问当前用户不是一个好主意.我将按如下方式实现:

It's not a good idea to access the current user inside the model. I would implement this as follows:

class Instance < ActiveRecord::Base
  has_many :users
  has_many :books
end

class User < ActiveRecord::Base
  belongs_to :instance
  has_many :books, :order => "created_at DESC"
  has_many :instance_books, :through => :instance, :source => :books,
                   :order => "created_at DESC"
end

class Book < ActiveRecord::Base
  belongs_to  :user
  belongs_to  :instance
end

与用户实例关联的书籍列表:

List of Books associated with the user instance:

current_user.instance_books

用户创建的图书列表:

current_user.books

创建新书:

current_user.books.create(:instance => current_user.instance, ..)

注意:

您的图书创建语法错误.build 方法以散列作为参数.您传递的是两个参数而不是一个.

Your book creation syntax is wrong. The build method takes hash as parameter. You are passing two arguments instead of one.

user.books.build(params[:book].merge(:instance => current_user.instance}))

或

user.books.build(params[:book].merge(:instance_id => current_user.instance_id}))

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