Question

我必须做一个可以评论其他评论的评论，并且我按照本教程here进行操作，但是当我尝试运行应用程序时，会出现以下错误：

Unable to autoload constant POST, expected /example/app/models/post.rb to define it

提取的来源（第79行附近）

def find_commentable
  @commentable = Comment.find_by_id(params[:comment_id]) if params[:comment_id]
  @commentable = POST.find_by_id(params[:post_id]) if params[:post_id]
end

而且我真的不明白，如果一个具有发布模型（为什么是这样），为什么会出现此错误：

模型发布：

class Post < ApplicationRecord
  belongs_to :city
  has_many :comments, as: :commentable
end

这是您需要的评论模型：

class Comment < ApplicationRecord
belongs_to :commentable, polymorphic: true
has_many :comments, as: :commentable
end

这是评论的控制者：

class CommentsController < ApplicationController
  before_action :set_comment, only: [:show, :edit, :update, :destroy]
  before_action :find_commentable

  # GET /comments
  # GET /comments.json
  def index
    @comments = Comment.all
  end

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

  # GET /comments/new
  def new
    @comment = Comment.new
  end

  # GET /comments/1/edit
  def edit
  end

  # POST /comments
  # POST /comments.json
  def create
    @comment = @commentable.comments.new comment_params
    #@comment = Comment.new(comment_params)

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

  # PATCH/PUT /comments/1
  # PATCH/PUT /comments/1.json
  def update
    respond_to do |format|
      if @comment.update(comment_params)
        format.html { redirect_to @comment, notice: 'Comment was successfully updated.' }
        format.json { render :show, status: :ok, location: @comment }
      else
        format.html { render :edit }
        format.json { render json: @comment.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /comments/1
  # DELETE /comments/1.json
  def destroy
    @comment.destroy
    respond_to do |format|
      format.html { redirect_to comments_url, notice: 'Comment was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

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

    # Never trust parameters from the scary internet, only allow the white list through.
    def comment_params
      params.require(:comment).permit(:publication, :author, :content, :reputation, :creation_date)
    end

    def find_commentable
      @commentable = Comment.find_by_id(params[:comment_id]) if params[:comment_id]
      @commentable = POST.find_by_id(params[:post_id]) if params[:post_id]
    end
end

我真的不知道为什么程序无法自动加载Post。

无法自动加载常量POST，请按/example/app/models/post.rb进行定义

0 个答案: