从多个主题获取所有帖子

Question

我想显示仅与用户的所有主题相关的所有帖子。 我已经尝试过，但我总是出错。这太令人困惑了，因为它与我有很多关系。这是模型。

class Post
  include Mongoid::Document
  include Mongoid::Timestamps

  field :content, type: String
  field :locked , type: Boolean
  field :unlocked_at , type: Date

  validates_presence_of :content

  belongs_to :subject
  belongs_to :user , inverse_of: :posted_by , class_name: "User"
  has_many :comments,dependent: :delete
  has_many :video_attachments , inverse_of: :posts , dependent: :delete
  accepts_nested_attributes_for :video_attachments, autosave: true
  accepts_nested_attributes_for :comments, autosave: true

end

require "mongoid/token"
class Subject
  include Mongoid::Document
  include Mongoid::Token

  field :title , type: String
  field :desc , type: String

  has_and_belongs_to_many :admins , inverse_of: :admin_of , class_name: "User"
  has_and_belongs_to_many :students , inverse_of: :student_of , class_name: "User"
  has_many :posts
  token length: 6

end

class User
  include Mongoid::Document
  authenticates_with_sorcery!
  mount_uploader :avatar , AvatarUploader

  #fields
  #field :email , type: String
  field :id_number , type: String
  field :crypted_password , type: String
  field :salt , type: String
  field :fname , type: String
  field :lname , type: String
  field :mname , type: String
  field :avatar
  field :gender , type: Boolean
  field :role , type: String , default: "Student"


  #relations
  has_and_belongs_to_many :admin_of , inverse_of: :admins , class_name: "Subject"
  has_and_belongs_to_many :student_of , inverse_of: :students , class_name: "Subject"
  has_one :user_detail 
  has_many :posts , inverse_of: :user , class_name: "Post"
  has_many :comments
  accepts_nested_attributes_for :user_detail , autosave: true


end

Answer 1

current_user = User.find("5492ca884d696c7bbe040000")
posts = current_user.student_of.collect(&:posts).flatten