在Valuations＃new中的ActionController :: UrlGenerationError

Question

我已经阅读了与UrlGenerationError相关的其他SO文章，这些文章似乎指向一个单词的单一化或多元化，但我不认为这是问题在这里。

当我从估价/ _form.html.erb中删除时

<%= render "comments/comments" %>
<%= render "comments/form" %>

使用:name＆amp;提交_form。 :tag_list，读过

<%= render "comments/comments" %>
<%= render "comments/form" %>

然后刷新。什么是零交易？

路由

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  resources :valuations do
    resources :comments
  end

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comments_controller

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class CommentsController < ApplicationController
	before_action :load_commentable
  before_action :set_comment, only: [:show, :edit, :update, :destroy]
  before_action :logged_in_user, only: [:create, :destroy]

	def index
		@comments = @commentable.comments
	end

	def new
		@comment = @commentable.comments.new
	end

	def create
		@comment = @commentable.comments.new(comment_params)
		if @comment.save
			@comment.create_activity :create, owner: current_user 
			redirect_to @commentable, notice: "comment created."
		else
			render :new
		end
	end

	def edit
		@comment = current_user.comments.find(params[:id])
	end

	def update
		@comment = current_user.comments.find(params[:id])
		if @comment.update_attributes(comment_params)
			redirect_to @commentable, notice: "Comment was updated."
		else
			render :edit
		end
	end

	def destroy
		@comment = current_user.comments.find(params[:id])
		@comment.destroy
		@comment.create_activity :destroy, owner: current_user
		redirect_to @commentable, notice: "comment destroyed."
	end

private
  def set_comment
    @comment = Comment.find(params[:id])
  end

	def load_commentable
		resource, id = request.path.split('/')[1, 2]
		@commentable = resource.singularize.classify.constantize.find(id)
	end

	def comment_params
		params.require(:comment).permit(:content, :commentable)
	end
end

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valuations_controller

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class ValuationsController < ApplicationController
  before_action :set_valuation, only: [:show, :edit, :update, :destroy]
  before_action :logged_in_user, only: [:create, :destroy]

  def index
    if params[:tag]
      @valuations = Valuation.tagged_with(params[:tag])
    else
      @valuations = Valuation.order('RANDOM()')
    end
  end

  def show
    @valuation = Valuation.find(params[:id])
    @commentable = @valuation
    @comments = @commentable.comments
    @comment = Comment.new
  end

  def new
    @valuation = current_user.valuations.build
    @commentable = @valuation
    @comments = @commentable.comments
    @comment = Comment.new
  end

  def edit
  end

  def create
    @valuation = current_user.valuations.build(valuation_params)
    if @valuation.save
      redirect_to @valuation, notice: 'Value was successfully created'
    else
      @feed_items = []
      render 'pages/home'
  end
end

  def update
    if @valuation.update(valuation_params)
      redirect_to @valuation, notice: 'Value was successfully updated'
    else
      render action: 'edit'
  end
end

  def destroy
    @valuation.destroy
    redirect_to valuations_url
  end

private
    def set_valuation
      @valuation = Valuation.find(params[:id])
    end

    def correct_user
      @valuation = current_user.valuations.find_by(id: params[:id])
      redirect_to valuations_path, notice: "Not authorized to edit this valuation" if @valuation.nil?
    end

    def valuation_params
      params.require(:valuation).permit(:name, :private_submit, :tag_list, :content, :commentable, :comment)
    end
end

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评论/ _form.html.erb

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<%= form_for [@commentable, @comment] do |f| %>
  <% if @comment.errors.any? %>
    <div class="error_messages">
      <h2>Please correct the following errors.</h2>
      <ul>
      <% @comment.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

<div class="america">

  <div class="form-group">
    <%= f.text_area :content, rows: 4, class: 'form-control', placeholder: 'Enter Comment' %>
  </div>

  <div class="america2">
  <%= button_tag(type: 'submit', class: "btn") do %>
  <span class="glyphicon glyphicon-plus"></span> Comment
  <% end %>

</div>

<% end %>

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非常感谢你的时间。

Answer 1

当您拥有这样的嵌套资源时，用于创建评论的网址看起来像/valuations/123/comments，其中123是评估的ID - 如果没有评估ID，则无法生成此网址。

在您的估值＃新页面上，估值（即@commentable）是未保存的对象，因此它还没有ID，因此错误提示valuation_id。另外一个嵌套在另一个窗体中的窗体是无效的html，会导致奇怪的行为。另一方面，在您的展示页面上，估值确实有一个ID，所以事情应该按原样运作。

如果您想一次性创建评估及其初始评论，那么您应该使用accepts_nested_attributes_for和fields_for将评论的字段添加到您的评估表单中（还有其他方式，但accepts_nested_attributes_for是内置于rails中的内容）