ruby-on-rails - Rails has_many :through with collection_select form helper

Question

我在创建一个通过关联保存我的 has_many 的表单时遇到问题。我已经通过发布 json 成功保存了，但表单对我来说还不起作用。表单提交创建的请求参数将无法正常工作。任何帮助我找到解决方案的帮助都会帮助我避免在这方面浪费更多时间。先谢谢了。

已编辑 - 添加了 forms_for 尝试和创建的 params json，但在底部效果不佳 -

有效的 Json post 请求参数:

{
    "author": {
        "name": "Author Name",
        "post_authors_attributes": [
          {"post_id":"1"},
          {"post_id":"2"},
          {"post_id":"3"}
        ]
    }
}

Rails 表单生成的参数不保存。

{
    "author": {
        "name": "assd",
        "post_authors_attributes": [
            "",
            "2",
            "3"
        ]
    }
}

...以及相关的代码示例...

作者模型

class Author < ActiveRecord::Base
  has_many :post_authors
  has_many :posts, :through => :post_authors
  accepts_nested_attributes_for :post_authors
end

帖子模型(目前仅对作者有很多帖子进行操作，而不是相反)

class Post < ActiveRecord::Base
end

PostAuthor模型

class PostAuthor < ActiveRecord::Base
  belongs_to :post
  belongs_to :author
end

作者 Controller 新建/创建操作

  # GET /authors/new
  def new
    @author = Author.new
    @author.post_authors.build
  end

  # POST /authors
  # POST /authors.json
  def create
    @author = Author.new(params)

    respond_to do |format|
      if @author.save
        format.html { redirect_to @author, notice: 'Author was successfully created.' }
        format.json { render :show, status: :created, location: @author }
      else
        format.html { render :new }
        format.json { render json: @author.errors, status: :unprocessable_entity }
      end
    end
  end

作者/_form.html.erb

<%= form_for(@author) do |f| %>
  <% if @author.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@author.errors.count, "error") %> prohibited this author from being saved:</h2>

      <ul>
      <% @author.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.label :name %><br>
    <%= f.text_field :name %>
  </div>

    <%= collection_select(:author, :post_authors_attributes, Post.all, :id, :title,
                                     {include_blank: false, :selected => @author.posts.map(&:id)},
                                     {:multiple => true}) %>

  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

架构

ActiveRecord::Schema.define(version: 20150120190715) do

  create_table "authors", force: :cascade do |t|
    t.string   "name"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "post_authors", force: :cascade do |t|
    t.integer  "post_id"
    t.integer  "author_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "posts", force: :cascade do |t|
    t.string   "title"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

end

编辑 -- 添加详细信息 --只是出于尽职调查，我还尝试使用 fields_for，但它会产生更困惑的 json，并且不会保存到数据库中。我不知道“0”键从何而来。我被困在这个问题上，任何帮助将不胜感激。

字段

  <div class="field">
    <%= f.fields_for :post_authors, @author.post_authors do |posts_form| %>
        <%= f.label :Posts %><br>
        <%= posts_form.collection_select(:post_id, Post.all, :id, :title,
                                         {include_blank: false, :selected => @author.posts.map(&:id)},
                                         {:multiple => true}) %>

    <% end %>
  </div>

生成参数 to_json

{
    "author": {
        "name": "test",
        "post_authors_attributes": {
            "0": {
                "post_id": [
                    "",
                    "1",
                    "2",
                    "3"
                ]
            }
        }
    }
}

Answer 1

对于任何遇到相同类型问题的人，我终于设法让它与以下 collection_select 一起使用:

      <%= f.collection_select(:feature_ids, Feature.all, :id, :name,
                              {include_blank: false, :include_hidden => false, :selected => @property.features.map(&:id)},
                              {:multiple => true}) %>