多态模型上的回形针嵌套属性未保存 (RAILS)

Question

我一辈子都弄不明白为什么我的回形针附件的某些属性没有通过嵌套属性保存到数据库中。我的 post 有一个附件，但没有保存 :attachment 属性的 :media 参数，但正在创建附件对象。我想我的强参数的传递方式有些混乱。提前致谢。

无参数

  media_file_name: nil, media_content_type: nil, media_file_size: nil, media_updated_at: nil>

IRB：

 irb(main):001:0> p = Post.last
      Post Load (0.1ms)  SELECT  "posts".* FROM "posts"  ORDER BY "posts"."id" DESC LIMIT 1
    => #<Post id: 40, body: "test info", expiration: 1467065130586, created_at: "2016-06-27 21:05:41", updated_at: "2016-06-27 21:05:41">
    irb(main):002:0> p.attachment
      Attachment Load (0.2ms)  SELECT  "attachments".* FROM "attachments" WHERE "attachments"."attachable_id" = ? AND "attachments"."attachable_type" = ? LIMIT 1  [["attachable_id", 40], ["attachable_type", "Post"]]
    => #<Attachment id: 26, attachable_id: 40, attachable_type: "Post", created_at: "2016-06-27 21:05:41", updated_at: "2016-06-27 21:05:41", media_file_name: nil, media_content_type: nil, media_file_size: nil, media_updated_at: nil>
    irb(main):003:0>

架构：

ActiveRecord::Schema.define(version: 20160627165514) do

  create_table "attachments", force: :cascade do |t|
    t.integer  "attachable_id"
    t.string   "attachable_type"
    t.datetime "created_at",         null: false
    t.datetime "updated_at",         null: false
    t.string   "media_file_name"
    t.string   "media_content_type"
    t.integer  "media_file_size"
    t.datetime "media_updated_at"
  end

  add_index "attachments", ["attachable_type", "attachable_id"], name: "index_attachments_on_attachable_type_and_attachable_id"

  create_table "posts", force: :cascade do |t|
    t.text     "body"
    t.integer  "expiration", limit: 8
    t.datetime "created_at",           null: false
    t.datetime "updated_at",           null: false
  end

end

Post 型号：

class Post < ActiveRecord::Base
    has_one :attachment, as: :attachable, dependent: :destroy
    accepts_nested_attributes_for :attachment
end

Post 控制器：

class PostsController < ApplicationController

    def show
        #I don't need this.
    end

    def index
        @posts = Post.all
    end

    def new
        @post = Post.new
        @post.build_attachment
    end

    def create
        @post = Post.new(post_params)
        @post.build_attachment
        if @post.save
            respond_to do |format|
                format.html {redirect_to(posts_path, notice:"Post succesfully created")}
                format.js  
            end
        else
            render :new
        end
    end


    private

    def post_params
      params.require(:post).permit(:body,:expiration, attachment_attributes: [:media])
    end


end

附件型号：

class Attachment < ActiveRecord::Base

    belongs_to :attachable, polymorphic:true
    has_attached_file :media
end

HTML 表格：

    <%=form_for(@post, url: posts_path, html:{multipart:true}) do |form|%>
        <%=form.text_area :body%>

        <%=fields_for(:attachment) do |ff|%>
            <%= ff.file_field :media %>
        <%end%>


    <%=form.hidden_field :expiration%>
    <%=form.submit "Post", class: "post-submit-button"%>



<%end%>

登录哑巴：

Started POST "/posts" for ::1 at 2016-06-27 16:05:41 -0500
Processing by PostsController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"/b54OJOBJIaR551MAHDujCxjciI7OAx93EQAVrugCz0xtYnafaSH4widYOftZJUbDHLfmI6jly5eG5AxCCNJbQ==", "post"=>{"body"=>"test info", "expiration"=>"1467065130586"}, "attachment"=>{"media"=>"IMG_1004.jpg"}, "commit"=>"Post"}
   (0.1ms)  begin transaction
  SQL (0.3ms)  INSERT INTO "posts" ("body", "expiration", "created_at", "updated_at") VALUES (?, ?, ?, ?)  [["body", "test info"], ["expiration", 1467065130586], ["created_at", "2016-06-27 21:05:41.321484"], ["updated_at", "2016-06-27 21:05:41.321484"]]
  SQL (0.1ms)  INSERT INTO "attachments" ("attachable_type", "attachable_id", "created_at", "updated_at") VALUES (?, ?, ?, ?)  [["attachable_type", "Post"], ["attachable_id", 40], ["created_at", "2016-06-27 21:05:41.323335"], ["updated_at", "2016-06-27 21:05:41.323335"]]
   (1.4ms)  commit transaction
Redirected to http://localhost:3000/posts
Completed 302 Found in 8ms (ActiveRecord: 1.9ms)


Started GET "/posts" for ::1 at 2016-06-27 16:05:41 -0500
Processing by PostsController#index as HTML
  Rendered layouts/_user_menu.html.erb (0.1ms)
  Rendered posts/index.html.erb within layouts/application (1.8ms)
Completed 200 OK in 26ms (Views: 25.8ms | ActiveRecord: 0.0ms)

Answer 1

您没有将 fields_for 绑定到表单。试试这个：

<%=form_for(@post, url: posts_path, html:{multipart:true}) do |form|%>
  <%=form.text_area :body%>
  <%= form.fields_for(:attachment) do |ff|%>
    <%= ff.file_field :media %>
  <% end %>
  <%=form.hidden_field :expiration%>
  <%=form.submit "Post", class: "post-submit-button"%>
<%end%>

多态模型上的回形针嵌套属性未保存 (RAILS)

Paperclip Nested attributes on polymorphic model not getting saved (RAILS)

polymorphism

ruby-on-rails

paperclip

nested-attributes

strong-parameters