Rails的Mongoid時間戳似乎不工作

Question

這裏是我的模型message.rb：

class Message 
    include Mongoid::Document 
    include Mongoid::Timestamps::Created 
    embedded_in :room 

    field :content 
    field :user_id # That's the guest_id; room_id if it's a room's owner message. 

end 

時間戳* created_at *應該由Mongoid自動創建，但目前還沒有這樣的屬性Message.created_at在數據庫。我不明白爲什麼。

的embeds_many模型：

class Room 
    include Mongoid::Document 
    include ActiveModel::SecurePassword 
    embeds_one :guest 
    embeds_many :messages 

    has_secure_password 
    field :password_digest 
    field :owner_name 
    field :url 

end 

這是我創建的房間：

def create 

    @room = Room.new(room_params) 
    @room.password_confirmation = @room.password # Easy way to bypass the has_secure_password confirmation. 
    @room.url = generate_url 
    respond_to do |format| 
     if @room.save 
     session[@room.id.to_s.to_sym] = true 
     format.html { redirect_to "/chat/" + @room.url, notice: 'Room was successfully created.' } 
     format.json { render action: 'show', status: :created, location: @room } 
     else 
     format.html { render action: 'new' } 
     format.json { render json: @room.errors, status: :unprocessable_entity } 
     end 
    end 
    end 

這是我如何創建消息：

def write_message 
    @room = Room.find(params[:id]) 
    @room.messages.build(content: params[:message], user_id: params[:user_id]) 
    if @room.save 
     render json: true 
    else 
     render json: @room.errors, status: :unprocessable_entity 
    end 

    end 

我使用Rails 4.0.0和Mongoid 4.0.0.beta1。

Answer 1

嘗試修改房類是

class Room 
    ... 
    embeds_many :messages, cascade_callbacks: true 
    ... 
end