Rails has_many :through with collection_select 表单助手

Question

我在创建将保存我的 has_many 的表单时遇到问题：通过关联。我已经通过发布 json 成功保存了，但是这些表格还对我不起作用。表单提交创建的请求参数将无法正常工作。任何指向我解决方案的帮助都将帮助我避免在这方面浪费更多时间。预先感谢。

已编辑 -- 添加了 forms_for 尝试和创建的在底部无法正常工作的参数 json --

有效的 Json 发布请求参数：

{
    "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（目前只对作者工作有很多帖子，反之不行）

class Post < ActiveRecord::Base
end

PostAuthor 模型

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

作者控制器新建/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 -- 只是为了尽职调查，我也尝试过使用fields_for，但它会产生更混乱的json，不会保存到数据库中。我不知道“0”键是从哪里来的。我坚持这一点，任何帮助将不胜感激。

fields_for

  <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>

生成的参数 to_json

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

Answer 1

对于任何遇到同样问题的人，我终于设法让它与以下 collection_select 一起工作：

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

Answer 2

authors/_form.html.erb:

<%= fields_for(@author_book) do |ab| %>
  <div class="field">
    <%= ab.label "All Books" %><br>
    <%= collection_select(:books, :id, @all_books, :id, :name, {:selected => @author.books.map(&:id)}, {multiple: true}) %>
  </div>
<% end %>

authors_controller.rb:

class AuthorsController < ApplicationController
  before_action :set_author, only: [:show, :edit, :update, :destroy]

  # GET /authors
  # GET /authors.json
  def index
    @authors = Author.all
  end

  # GET /authors/1
  # GET /authors/1.json
  def show
  end

  # GET /authors/new
  def new
    @author = Author.new
    get_books
    respond_to do |format|
    format.html
    format.json { render json: @author }
  end

  end

  # GET /authors/1/edit
  def edit
    get_books
  end
  # POST /authors
  # POST /authors.json
  def create

    @author = Author.new(author_params)
    params[:books][:id].each do |book|
      if !book.empty?
        @author.authorbooks.build(:book_id => book)
      end
    end

    #binding.pry
    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

  # PATCH/PUT /authors/1
  # PATCH/PUT /authors/1.json
  def update
    #binding.pry
    respond_to do |format|
      if @author.update(author_params)

        @author.books = []
        params[:books][:id].each do |book|
          if !book.empty?
            @author.books << Book.find(book)
          end
        end

        format.html { redirect_to @author, notice: 'Author was successfully updated.' }
        format.json { render :show, status: :ok, location: @author }
      else
        format.html { render :edit }
        format.json { render json: @author.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /authors/1
  # DELETE /authors/1.json
  def destroy
    @author.destroy
    respond_to do |format|
      format.html { redirect_to authors_url, notice: 'Author was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_author
      @author = Author.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def author_params
      params.require(:author).permit(:name,:authorbooks_attributes => [:id,:book_ids => []])

    end

    def get_books
      @all_books = Book.all
      @author_book = @author.authorbooks.build
    end

    # def create_params
    #   params.require(:authorbooks).permit(:author_id,book_id: [])
    # end
end