Rails has_many :通过 collection_select 表单助手

Question

我在创建将保存我的 has_many :through 关联的表单时遇到问题。我已通过 posting json 成功保存，但这些表格还不适用于我。表单提交创建的请求参数是行不通的。任何帮助我找到解决方案的帮助都会帮助我避免在这上面浪费更多时间。先谢谢了。

已编辑——添加了forms_for尝试和创建的参数json，但在底部效果不佳——

Json post 请求有效的参数：

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

Rails 形成不保存的生成参数。

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

...以及相关代码示例...

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

Post型号（目前只在Author上工作有很多Post，不反 )

class Post < ActiveRecord::Base
end

Post作者模型

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

作者控制器new/create 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

authors/_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 -- 出于谨慎考虑，我也尝试过使用 fields_for，但它会产生更混乱的 json，并且不会保存到数据库中。我不知道“0”键是从哪里来的。我坚持这个，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

对于遇到同样问题的任何人，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

Rails has_many :通过 collection_select 表单助手

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