如何在我的应用程序ruby on rails上添加评论功能？

Question

我无法在Rails应用程序中添加评论系统。我遵循了rails指南see rails guide started，甚至从一个新的rails应用程序开始。但是我不确定我是否正确遵循了指南。请帮助我弄清楚我在做什么错。

CourseController

    class CoursesController < ApplicationController
  before_action :authenticate_user!
  before_action :set_course, only: [:show, :edit, :update, :destroy]
  before_action :find_matieres, only: [:index, :show, :new, :edit]

  # GET /courses
  # GET /courses.json
  def index
    @courses = Course.all.order('created_at desc')
    @matieres = Matiere.all
  end

  # GET /courses/1
  # GET /courses/1.json
  def show
    @courses = Course.all.order('created_at desc')    
  end

  # GET /courses/new
  def new
    @course = current_user.courses.build
  end

  # GET /courses/1/edit
  def edit
  end

  # POST /courses
  # POST /courses.json
  # def create
  def create
    @course = current_user.courses.build(course_params)

    respond_to do |format|
      if @course.save
        format.html { redirect_to @course, notice: 'Cours crée avec succes.' }
        format.json { render :show, status: :created, location: @course }
      else
        format.html { render :new }
        format.json { render json: @course.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /courses/1
  # PATCH/PUT /courses/1.json
  def update
    respond_to do |format|
      if @course.update(course_params)
        format.html { redirect_to @course, notice: 'Cours mise a jour avec success..' }
        format.json { render :show, status: :ok, location: @course }
      else
        format.html { render :edit }
        format.json { render json: @course.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /courses/1
  # DELETE /courses/1.json
  def destroy
    @course.destroy
    respond_to do |format|
      format.html { redirect_to courses_url, notice: 'Cours supprimé avec success.' }
      format.json { head :no_content }
    end
  end

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

    # Never trust parameters from the scary internet, only allow the white list through.
    def course_params
      params.require(:course).permit(:title, :content, :user_id, :matiere_id)
    end

    def find_matieres
      @matieres = Matiere.all.order('created_at desc')
    end
end

CommentController

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

  # 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
    @course = Course.find(params[:course_id])
    @comment = @course.comments.build(comment_params)
    respond_to do |format|
      if @comment.save
        format.html { redirect_to @course, notice: 'Comment was successfully created.' }
        format.json { render :show, status: :created, location: @course }
      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 @course, notice: 'modification valide.' }
        format.json { render :show, status: :ok, location: @course }
      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 courses_url, notice: 'Comment was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private

    # => find course_id reference
    def set_course
      @course = Course.find(params[:course_id])

    end

    # 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(:content, :course_id)

    end
end

模型课程

class Course < ApplicationRecord

#RELATIONS
belongs_to :matiere
belongs_to :user
has_many :comments



#VALIDATES
 validates :title, :content, presence: true,
                            length: { minimum: 20 }

 #validates_processing_of :image
 #validate :image_size_validation


#PRIVATE
  private
     # def image_size_validation
      # errors[:image] << "fichier trop lourd, reduire la taille a 900KB" if image.size > 0.9.megabytes
      #end
end

模型注释

    class Comment < ApplicationRecord
#RELATIONS
  belongs_to :course

  #VALIDAES
  validates :comment ,presence:true,
                    length: { minimum: 10}
end

评论形式

<!-- Comments Form -->

<div class="card my-4">
<h5 class="card-header">Interaction</h5>
<div class="card-body">

   <div class="form-group">
    <%= f.input :content, required: true, input_html: { class: 'textarea' }, wrapper: false, label_html: { class: 'label' }, placeholder:'Ajouter une question ou un commentaire...' %>
    </div>
    <button type="submit" class="btn btn-primary"><i class="fa fa-location-arrow" aria-hidden="true"></i> Ajouter</button>
 </div>
</div>

评论文件夹中的_comment.html.erb

 <div class="box">
  <article class="media">
    <!-- avatar user comment/!-->
    <div class="media-left">
      <figure class="image is-48x48 is-rounded">
        <%= link_to  edit_user_registration_path, class: "button" do %>
          <img src="https://bulma.io/images/placeholders/32x32.png">
        <% end %>
      </figure>
    </div>
    <!-- comment + meta info user /!-->
    <div class="media-content">
      <div class="content">
        <p>
          <!-- ADD
            Upvote/downvote comment by over user
            Username
            /!-->   
        </p><br>
        <p><strong>Commenaire : </strong>
          <%= comment.content %>
        </p>
      </div>
    </div>
  </article>
</div>

course / show.html.erb用于带有注释的印刷内容课程

<div class="container show_course">
  <!-- meta description matiere/!-->
    <small class="has-text-grey-lighter">
      Sujet: <%= link_to @course.matiere.matiere, @course.matiere %>
    </small><br>
    <!-- course title/!-->
  <h3 class="title title-discu-show">
    <%= @course.title %>        
  </h3>
  <!-- meta info user/!-->
  <%= render 'shared/users/data_users' %>   
  <!--content course/!-->
  <div class="card-content">
    <%= sanitize(@course.content) %>
  </div>
  <!-- Add option feature/
     ...
          modifier
          bookmark
          follow
          add your Biblio
          delete
          signaler
  /!--->
  <div class="level">
    <div class="level-right">
      <% if course_author(@course) %>
        <div class="buttons">
          <%= link_to 'Modifier', edit_course_path(@course), class:'button'%>            
        </div>
      <% end %>
    </div>
  </div>

  <!-- print comments/!-->
  <div id="course-comments.content">
    <!-- section commentaire/!-->
    <%= render @course.comments %>
  </div>
  <br>
    <!-- form comments/!-->
  <div class="course-comment-form">
    <%= render 'comments/form' %>  
  </div>   
</div>

routes.rb

 Rails.application.routes.draw do
  resources :accounts   
  resources :matieres


  resources :courses do
   resources :comments
  end   

  root to:'home#index'
  devise_for :users, controllers: { registrations: 'registrations' }
end

schema.rb

create_table "comments", force: :cascade do |t|
    t.text "content"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.bigint "course_id"
    t.bigint "user_id"
  end

  create_table "courses", force: :cascade do |t|
    t.string "title"
    t.text "content"
    t.string "image_course"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.string "slug"
    t.bigint "matiere_id"
    t.bigint "user_id"
    t.index ["matiere_id"], name: "index_courses_on_matiere_id"
    t.index ["user_id"], name: "index_courses_on_user_id"
  end

控制台消息注意：**** ROLLBACK **在线28 **]

Started POST "/courses/4/comments" for ::1 at 2019-11-30 11:30:11 +0000
Processing by CommentsController#create as JS
  Parameters: {"utf8"=>"✓", "comment"=>{"content"=>"100 ans, c'est très long. Je vous présente un pays qui n'a mis que deux ans à devenir un pays du tiers monde issu d'un pays riche et développé. C'est toujours un pays du tiers monde. Fortement et fièrement."}, "course_id"=>"4"}
  Course Load (1.3ms)  SELECT  "courses".* FROM "courses" WHERE "courses"."id" = $1 LIMIT $2  [["id", 4], ["LIMIT", 1]]
  ↳ app/controllers/comments_controller.rb:27
   (0.8ms)  BEGIN
  ↳ app/controllers/comments_controller.rb:28
   (0.6ms)  ROLLBACK
  ↳ app/controllers/comments_controller.rb:28
Completed 500 Internal Server Error in 33ms (ActiveRecord: 3.2ms)



NoMethodError - undefined method `comment' for #<Comment:0x0000555ccc6a8528>
Did you mean?  content:
  app/controllers/comments_controller.rb:28:in `create'

source=rack-timeout id=ca133680-ce55-4b88-99ce-16fd3d1f01a0 timeout=15000ms service=130ms state=completed

但我必须在其中定义注释

关于终端错误消息说：

 NoMethodError - undefined method `comment' for #<Comment:0x00007f04245dc0a8>
Did you mean?  content:
  app/controllers/comments_controller.rb:33:in `block in create'
  app/controllers/comments_controller.rb:32:in `create'

Answer 1

在您的评论模型中，没有“评论”字段。您只有一个“内容”字段。您的问题在这里

validates :comment ,presence:true,
                    length: { minimum: 10}

在您的评论模型中。我想你的意思是>

validates :content, presence:true,
                    length: { minimum: 10}