Ruby on rails 未定义的方法'song#u id'；[第4条]

快速分解我的应用程序：我有一个歌曲、评论和用户模型。用户可以上传歌曲，并发表评论

简言之，当我提交一首歌曲时，我会遇到以下错误。我已经了解了Ryan Bates的做法，我的代码是相同的。不确定为什么没有关联歌曲id。请告知：）

完整的应用程序代码可在此处查看：www.github.com/apane/leap

错误消息：

NoMethodError in Songs#show

Showing /Users/apane/Downloads/leap/app/views/comments/_form.html.erb where line #17 raised:

undefined method `song_id' for #<Song:0x007f8e71f77d10>

<div class="row">
<div class="large-6 columns">
<div class="field">
<%= f.hidden_field :song_id %>
<p>
<%= f.label :author_name, 'Name' %><br />
<%= f.text_field :author_name %>

NoMethodError在歌曲中#show
显示/Users/apane/Downloads/leap/app/views/comments/_form.html.erb，其中第17行出现：
未定义的方法“song_id”#

comments#u form.html.erb

<%= form_for @comment do |f| %>
  <% if @comment.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@comment.errors.count, "error") %> prohibited this comment from being saved:</h2>

      <ul>
      <% @comment.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

    <div class="row">
        <div class="large-6 columns">
  <div class="field">
     <%= f.hidden_field :song_id %>
      <p>
        <%= f.label :author_name, 'Name' %><br />
        <%= f.text_field :author_name %>
      </p>
      <p>
        <%= f.label :site_url, 'Website URL' %><br />
        <%= f.text_field :site_url %>
      </p>
      <p>
        <%= f.label :content, 'Comment' %><br />
        <%= f.text_area :content, :rows => '12', :cols => 35 %>
      </p>
      <p><%= f.submit "Submit" %></p>
    <% end %>
    </div></div></div>

class SongsController < ApplicationController
  before_filter :authenticate_user!, only: [:create ,:edit, :update, :destroy]
  before_action :set_song, only: [:show, :edit, :update, :destroy]

  # GET /Songs
  # GET /Songs.json
  def index
    @songs = Song.all
  end

  # GET /Songs/1
  # GET /Songs/1.json
  def show
    @comment = @song
  end

  # GET /Songs/new
  def new
    @song = Song.new
  end

  # GET /Songs/1/edit
  def edit
  end

  # POST /Songs
  # POST /Songs.json
  def create
    @song = Song.new(song_params)

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

  # PATCH/PUT /Songs/1
  # PATCH/PUT /Songs/1.json
  def update
    respond_to do |format|
      if @song.update(song_params)
        format.html { redirect_to @song, notice: 'Song was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @song.errors, status: :unprocessable_entity }
      end
    end
  end

  # Song /Songs/1
  # Song /Songs/1.json
  def destroy
    @song.destroy
    respond_to do |format|
      format.html { redirect_to songs_url }
      format.json { head :no_content }
    end
  end

  private

    def set_song
       @song = Song.find(params[:id])
     end

     def song_params
       params.require(:song).permit(:title, :artist, :bio, :track, :user_id)
     end
  end

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



  # GET /comments/new
  def new
  end

  # GET /comments/1/edit
  def edit
  end

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

    respond_to do |format|
      if @comment.save
        format.html { redirect_to song_url(@comment.song_id), notice: 'Comment was successfully created.'  }
        format.json { render action: 'show', status: :created, location: @comment}
      else
        format.html { render action: '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 song_url(@comment.song_id), notice: 'Comment was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @comment.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /comments/1
  # DELETE /comments/1.json
  def destroy
    @comment.destroy
      redirect_to song_url(@comment.song_id)
    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(:song_id, :author_name, :site_url, :content, :user_id)
    end
end

禁止保存此评论：














'12'，：cols=>35%>

歌曲\u控制器.rb

<%= form_for @comment do |f| %>
  <% if @comment.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@comment.errors.count, "error") %> prohibited this comment from being saved:</h2>

      <ul>
      <% @comment.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

    <div class="row">
        <div class="large-6 columns">
  <div class="field">
     <%= f.hidden_field :song_id %>
      <p>
        <%= f.label :author_name, 'Name' %><br />
        <%= f.text_field :author_name %>
      </p>
      <p>
        <%= f.label :site_url, 'Website URL' %><br />
        <%= f.text_field :site_url %>
      </p>
      <p>
        <%= f.label :content, 'Comment' %><br />
        <%= f.text_area :content, :rows => '12', :cols => 35 %>
      </p>
      <p><%= f.submit "Submit" %></p>
    <% end %>
    </div></div></div>

class SongsController < ApplicationController
  before_filter :authenticate_user!, only: [:create ,:edit, :update, :destroy]
  before_action :set_song, only: [:show, :edit, :update, :destroy]

  # GET /Songs
  # GET /Songs.json
  def index
    @songs = Song.all
  end

  # GET /Songs/1
  # GET /Songs/1.json
  def show
    @comment = @song
  end

  # GET /Songs/new
  def new
    @song = Song.new
  end

  # GET /Songs/1/edit
  def edit
  end

  # POST /Songs
  # POST /Songs.json
  def create
    @song = Song.new(song_params)

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

  # PATCH/PUT /Songs/1
  # PATCH/PUT /Songs/1.json
  def update
    respond_to do |format|
      if @song.update(song_params)
        format.html { redirect_to @song, notice: 'Song was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @song.errors, status: :unprocessable_entity }
      end
    end
  end

  # Song /Songs/1
  # Song /Songs/1.json
  def destroy
    @song.destroy
    respond_to do |format|
      format.html { redirect_to songs_url }
      format.json { head :no_content }
    end
  end

  private

    def set_song
       @song = Song.find(params[:id])
     end

     def song_params
       params.require(:song).permit(:title, :artist, :bio, :track, :user_id)
     end
  end

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



  # GET /comments/new
  def new
  end

  # GET /comments/1/edit
  def edit
  end

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

    respond_to do |format|
      if @comment.save
        format.html { redirect_to song_url(@comment.song_id), notice: 'Comment was successfully created.'  }
        format.json { render action: 'show', status: :created, location: @comment}
      else
        format.html { render action: '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 song_url(@comment.song_id), notice: 'Comment was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @comment.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /comments/1
  # DELETE /comments/1.json
  def destroy
    @comment.destroy
      redirect_to song_url(@comment.song_id)
    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(:song_id, :author_name, :site_url, :content, :user_id)
    end
end

classsongscontroller

评论\u controller.rb

<%= form_for @comment do |f| %>
  <% if @comment.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@comment.errors.count, "error") %> prohibited this comment from being saved:</h2>

      <ul>
      <% @comment.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

    <div class="row">
        <div class="large-6 columns">
  <div class="field">
     <%= f.hidden_field :song_id %>
      <p>
        <%= f.label :author_name, 'Name' %><br />
        <%= f.text_field :author_name %>
      </p>
      <p>
        <%= f.label :site_url, 'Website URL' %><br />
        <%= f.text_field :site_url %>
      </p>
      <p>
        <%= f.label :content, 'Comment' %><br />
        <%= f.text_area :content, :rows => '12', :cols => 35 %>
      </p>
      <p><%= f.submit "Submit" %></p>
    <% end %>
    </div></div></div>

class SongsController < ApplicationController
  before_filter :authenticate_user!, only: [:create ,:edit, :update, :destroy]
  before_action :set_song, only: [:show, :edit, :update, :destroy]

  # GET /Songs
  # GET /Songs.json
  def index
    @songs = Song.all
  end

  # GET /Songs/1
  # GET /Songs/1.json
  def show
    @comment = @song
  end

  # GET /Songs/new
  def new
    @song = Song.new
  end

  # GET /Songs/1/edit
  def edit
  end

  # POST /Songs
  # POST /Songs.json
  def create
    @song = Song.new(song_params)

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

  # PATCH/PUT /Songs/1
  # PATCH/PUT /Songs/1.json
  def update
    respond_to do |format|
      if @song.update(song_params)
        format.html { redirect_to @song, notice: 'Song was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @song.errors, status: :unprocessable_entity }
      end
    end
  end

  # Song /Songs/1
  # Song /Songs/1.json
  def destroy
    @song.destroy
    respond_to do |format|
      format.html { redirect_to songs_url }
      format.json { head :no_content }
    end
  end

  private

    def set_song
       @song = Song.find(params[:id])
     end

     def song_params
       params.require(:song).permit(:title, :artist, :bio, :track, :user_id)
     end
  end

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



  # GET /comments/new
  def new
  end

  # GET /comments/1/edit
  def edit
  end

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

    respond_to do |format|
      if @comment.save
        format.html { redirect_to song_url(@comment.song_id), notice: 'Comment was successfully created.'  }
        format.json { render action: 'show', status: :created, location: @comment}
      else
        format.html { render action: '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 song_url(@comment.song_id), notice: 'Comment was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @comment.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /comments/1
  # DELETE /comments/1.json
  def destroy
    @comment.destroy
      redirect_to song_url(@comment.song_id)
    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(:song_id, :author_name, :site_url, :content, :user_id)
    end
end

class CommentsController

歌曲#show.html.erb

<p id="notice"><%= notice %>


    <p>
    <strong>Title:</strong>
    <%= @song.title %>
    </p>

    <p>
    <strong>Bio:</strong>
    <%= @song.bio %>
    </p>

    <p>
    <strong>Audio:</strong>
    <%= audio_tag (@song.track.url), controls: "controls", alt: "Please use chrome, ie, or safari" %>
    </p>


    <br /><br />


    <%= link_to 'Edit', edit_song_path(@song), class: "button small secondary"%> 
    <%= link_to 'Back', songs_path,  class: "button small secondary" %>


    <% unless @song.comments.empty? %>
      <h2><%= pluralize(@song.comments.size, 'comment') %></h2>

      <div id="comments">
      <% for comment in @song.comments %>
        <div class="comment">
          <strong><%= link_to_unless comment.site_url.blank?, h(comment.author_name), h(comment.site_url) %></strong>
          <em>on <%= comment.created_at.strftime('%b %d, %Y at %H:%M') %></em>
          <%=simple_format comment.content %>
          <p>
              <%= link_to "Edit", edit_comment_path(comment) %>
            <% end %>
              | <%= link_to "Destroy", comment, :method => :delete, :confirm => "Are you sure?" %>
          </p>
        </div>
      </div>
    <% end %>

    <h3>Add your comment:</h3>
    <%= render :partial => 'comments/form' %>

标题：


Bio:


音频：





在…上

|：删除，：确认=>“确定吗？”%>

添加您的评论：
'注释/表格'%>

您忘记在注释模型中添加关联

外接程序

song.rb

belongs_to :song

---

你的声音模型应该有这样一条线

在你的声音里 这将允许在视图和控制器中访问该变量

在您的comment.rb中，如果与歌曲有任何关联

---

除了设置关联本身之外，注释表还应该包含song_id列。如果您检查他的github帐户，他确实有。他只是忘了在模型上写下关联。如果列存在，那么

song\u id

方法也将存在。缺少的关联可能是一个错误，可能会导致

song

方法丢失，但不应导致此错误。我已将关联添加到注释模型中，但仍会收到相同的错误。我现在没有时间完全调试此错误，但请注意，它表示

Song

对象没有

Song\u id

方法，这听起来很合理：a

Song