多态关联未定义方法 'content'

Question

我关注了这个 railscasts 剧集：http://railscasts.com/episodes/154-polymorphic-association-revised?view=comments。

现在得到这个：

<%= 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="field">
    <%= f.text_area :content, rows: 8 %>
  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

我是不是在估值控制器中做错了什么，比如 valuations_params？

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
  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


class CommentsController < ApplicationController
    before_filter :load_commentable

    def index
        @comments = @commentable.comments
    end

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

    def create
        @comment = @commentable.comments.new(params[:comment])
        @comment.user = current_user
        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(params[:comment])
            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 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


class CreateComments < ActiveRecord::Migration
  def change
    create_table :comments do |t|
        t.text :content
        t.belongs_to :commentable, polymorphic: true

      t.timestamps null: false
    end
    add_index :comments, [:commentable_id, :commentable_type]
  end
end

class CreateValuations < ActiveRecord::Migration
  def change
    create_table :valuations do |t|
      t.string :name
      t.boolean :private_submit
      t.references :user, index: true

      t.timestamps null: false
    end
    add_foreign_key :valuations, :users
    add_index :valuations, [:user_id, :created_at]
  end
end

class Valuation < ActiveRecord::Base
 belongs_to :user
 has_many :comments, as: :commentable
  acts_as_taggable
  validates :name, presence: true
 scope :private_submit, -> { where(private_submit: true) }
 scope :public_submit, -> { where(private_submit: false) }
  include PublicActivity::Model
  tracked owner: ->(controller, model) { controller && controller.current_user }

  scope :randomize, -> do
   order('RANDOM()').
   take(1)
 end
end

class Comment < ActiveRecord::Base
 include PublicActivity::Common
 # tracked except: :update,  owner: ->(controller, model) { controller && controller.current_user }
 belongs_to :commentable, polymorphic: true
end

完整跟踪

activemodel (4.2.0.rc3) lib/active_model/attribute_methods.rb:433:in `method_missing'
actionview (4.2.0.rc3) lib/action_view/helpers/tags/base.rb:28:in `public_send'
actionview (4.2.0.rc3) lib/action_view/helpers/tags/base.rb:28:in `value'
actionview (4.2.0.rc3) lib/action_view/helpers/tags/base.rb:37:in `value_before_type_cast'
actionview (4.2.0.rc3) lib/action_view/helpers/tags/text_area.rb:17:in `block in render'
actionview (4.2.0.rc3) lib/action_view/helpers/tags/text_area.rb:17:in `delete'
actionview (4.2.0.rc3) lib/action_view/helpers/tags/text_area.rb:17:in `render'
actionview (4.2.0.rc3) lib/action_view/helpers/form_helper.rb:886:in `text_area'
actionview (4.2.0.rc3) lib/action_view/helpers/form_helper.rb:1322:in `text_area'
app/views/comments/_form.html.erb:14:in `block in _app_views_comments__form_html_erb__170709608867418685_70276962559280'
actionview (4.2.0.rc3) lib/action_view/helpers/capture_helper.rb:38:in `block in capture'
actionview (4.2.0.rc3) lib/action_view/helpers/capture_helper.rb:200:in `with_output_buffer'
haml (4.0.6) lib/haml/helpers/action_view_xss_mods.rb:5:in `with_output_buffer_with_haml_xss'
actionview (4.2.0.rc3) lib/action_view/helpers/capture_helper.rb:38:in `capture'
haml (4.0.6) lib/haml/helpers/action_view_mods.rb:52:in `capture_with_haml'
actionview (4.2.0.rc3) lib/action_view/helpers/form_helper.rb:444:in `form_for'
haml (4.0.6) lib/haml/helpers/action_view_mods.rb:139:in `form_for_with_haml'
haml (4.0.6) lib/haml/helpers/action_view_xss_mods.rb:28:in `form_for_with_haml_xss'
app/views/comments/_form.html.erb:1:in `_app_views_comments__form_html_erb__170709608867418685_70276962559280'
actionview (4.2.0.rc3) lib/action_view/template.rb:145:in `block in render'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:166:in `instrument'
actionview (4.2.0.rc3) lib/action_view/template.rb:333:in `instrument'
actionview (4.2.0.rc3) lib/action_view/template.rb:143:in `render'
actionview (4.2.0.rc3) lib/action_view/renderer/partial_renderer.rb:339:in `render_partial'
actionview (4.2.0.rc3) lib/action_view/renderer/partial_renderer.rb:310:in `block in render'
actionview (4.2.0.rc3) lib/action_view/renderer/abstract_renderer.rb:39:in `block in instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:164:in `instrument'
actionview (4.2.0.rc3) lib/action_view/renderer/abstract_renderer.rb:39:in `instrument'
actionview (4.2.0.rc3) lib/action_view/renderer/partial_renderer.rb:309:in `render'
actionview (4.2.0.rc3) lib/action_view/renderer/renderer.rb:47:in `render_partial'
actionview (4.2.0.rc3) lib/action_view/helpers/rendering_helper.rb:35:in `render'
haml (4.0.6) lib/haml/helpers/action_view_mods.rb:12:in `render_with_haml'
app/views/valuations/show.html.erb:13:in `_app_views_valuations_show_html_erb___1405174294651949311_70276963239480'
actionview (4.2.0.rc3) lib/action_view/template.rb:145:in `block in render'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:166:in `instrument'
actionview (4.2.0.rc3) lib/action_view/template.rb:333:in `instrument'
actionview (4.2.0.rc3) lib/action_view/template.rb:143:in `render'
actionview (4.2.0.rc3) lib/action_view/renderer/template_renderer.rb:54:in `block (2 levels) in render_template'
actionview (4.2.0.rc3) lib/action_view/renderer/abstract_renderer.rb:39:in `block in instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:164:in `instrument'
actionview (4.2.0.rc3) lib/action_view/renderer/abstract_renderer.rb:39:in `instrument'
actionview (4.2.0.rc3) lib/action_view/renderer/template_renderer.rb:53:in `block in render_template'
actionview (4.2.0.rc3) lib/action_view/renderer/template_renderer.rb:61:in `render_with_layout'
actionview (4.2.0.rc3) lib/action_view/renderer/template_renderer.rb:52:in `render_template'
actionview (4.2.0.rc3) lib/action_view/renderer/template_renderer.rb:14:in `render'
actionview (4.2.0.rc3) lib/action_view/renderer/renderer.rb:42:in `render_template'
actionview (4.2.0.rc3) lib/action_view/renderer/renderer.rb:23:in `render'
actionview (4.2.0.rc3) lib/action_view/rendering.rb:100:in `_render_template'
actionpack (4.2.0.rc3) lib/action_controller/metal/streaming.rb:217:in `_render_template'
actionview (4.2.0.rc3) lib/action_view/rendering.rb:83:in `render_to_body'
actionpack (4.2.0.rc3) lib/action_controller/metal/rendering.rb:32:in `render_to_body'
actionpack (4.2.0.rc3) lib/action_controller/metal/renderers.rb:37:in `render_to_body'
actionpack (4.2.0.rc3) lib/abstract_controller/rendering.rb:25:in `render'
actionpack (4.2.0.rc3) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (4.2.0.rc3) lib/action_controller/metal/instrumentation.rb:41:in `block (2 levels) in render'
activesupport (4.2.0.rc3) lib/active_support/core_ext/benchmark.rb:12:in `block in ms'
/Users/galli01anthony/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/benchmark.rb:294:in `realtime'
activesupport (4.2.0.rc3) lib/active_support/core_ext/benchmark.rb:12:in `ms'
actionpack (4.2.0.rc3) lib/action_controller/metal/instrumentation.rb:41:in `block in render'
actionpack (4.2.0.rc3) lib/action_controller/metal/instrumentation.rb:84:in `cleanup_view_runtime'
activerecord (4.2.0.rc3) lib/active_record/railties/controller_runtime.rb:25:in `cleanup_view_runtime'
actionpack (4.2.0.rc3) lib/action_controller/metal/instrumentation.rb:40:in `render'
actionpack (4.2.0.rc3) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (4.2.0.rc3) lib/action_controller/metal/implicit_render.rb:5:in `send_action'
actionpack (4.2.0.rc3) lib/abstract_controller/base.rb:198:in `process_action'
actionpack (4.2.0.rc3) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.2.0.rc3) lib/abstract_controller/callbacks.rb:20:in `block in process_action'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:151:in `block in halting_and_conditional'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:151:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:151:in `block in halting_and_conditional'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:234:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:234:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:234:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:234:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:92:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:92:in `_run_callbacks'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:734:in `_run_process_action_callbacks'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.0.rc3) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (4.2.0.rc3) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.2.0.rc3) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.0.rc3) lib/active_support/notifications.rb:164:in `instrument'
actionpack (4.2.0.rc3) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.2.0.rc3) lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
activerecord (4.2.0.rc3) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.2.0.rc3) lib/abstract_controller/base.rb:137:in `process'
actionview (4.2.0.rc3) lib/action_view/rendering.rb:30:in `process'
actionpack (4.2.0.rc3) lib/action_controller/metal.rb:195:in `dispatch'
actionpack (4.2.0.rc3) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.2.0.rc3) lib/action_controller/metal.rb:236:in `block in action'
actionpack (4.2.0.rc3) lib/action_dispatch/routing/route_set.rb:73:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
actionpack (4.2.0.rc3) lib/action_dispatch/routing/route_set.rb:42:in `serve'
actionpack (4.2.0.rc3) lib/action_dispatch/journey/router.rb:43:in `block in serve'
actionpack (4.2.0.rc3) lib/action_dispatch/journey/router.rb:30:in `each'
actionpack (4.2.0.rc3) lib/action_dispatch/journey/router.rb:30:in `serve'
actionpack (4.2.0.rc3) lib/action_dispatch/routing/route_set.rb:802:in `call'
omniauth (1.2.2) lib/omniauth/strategy.rb:186:in `call!'
omniauth (1.2.2) lib/omniauth/strategy.rb:164:in `call'
omniauth (1.2.2) lib/omniauth/builder.rb:59:in `call'
rack (1.6.0) lib/rack/etag.rb:24:in `call'
rack (1.6.0) lib/rack/conditionalget.rb:25:in `call'
rack (1.6.0) lib/rack/head.rb:13:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/flash.rb:260:in `call'
rack (1.6.0) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.6.0) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.2.0.rc3) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.2.0.rc3) lib/active_record/connection_adapters/abstract/connection_pool.rb:647:in `call'
activerecord (4.2.0.rc3) lib/active_record/migration.rb:378:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:88:in `call'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:88:in `_run_callbacks'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:734:in `_run_call_callbacks'
activesupport (4.2.0.rc3) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/reloader.rb:73:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/remote_ip.rb:78:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.2.0.rc3) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.2.0.rc3) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.2.0.rc3) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.2.0.rc3) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.2.0.rc3) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.2.0.rc3) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.6.0) lib/rack/methodoverride.rb:22:in `call'
rack (1.6.0) lib/rack/runtime.rb:18:in `call'
activesupport (4.2.0.rc3) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
rack (1.6.0) lib/rack/lock.rb:17:in `call'
actionpack (4.2.0.rc3) lib/action_dispatch/middleware/static.rb:113:in `call'
rack (1.6.0) lib/rack/sendfile.rb:113:in `call'
railties (4.2.0.rc3) lib/rails/engine.rb:518:in `call'
railties (4.2.0.rc3) lib/rails/application.rb:164:in `call'
rack (1.6.0) lib/rack/lock.rb:17:in `call'
rack (1.6.0) lib/rack/content_length.rb:15:in `call'
rack (1.6.0) lib/rack/handler/webrick.rb:89:in `service'
/Users/galli01anthony/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/webrick/httpserver.rb:138:in `service'
/Users/galli01anthony/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/webrick/httpserver.rb:94:in `run'
/Users/galli01anthony/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/webrick/server.rb:295:in `block in start_thread'

感谢您的宝贵时间。

Answer 1

正如我在评论中猜测的那样，未为您的 table comments.

定义字段 :content

您可以在 rails 控制台看到它：Comment.new.respond_to?(:content)，如果它响应 false。

如果您在迁移时遇到问题，请修复它们并从头开始重新生成数据库：删除数据库，删除文件 schema.rb 和 rake db:migrate.

如果您的迁移正常并且您的 schema.rb 有问题，这也适用。

编辑：当我检查你的代码时，我在你的 CommentsController at actions 中看到：create 和 update 你正在使用 params[:comment] 更新。我想你想改用 comment_params 方法。

多态关联未定义方法 'content'

Polymorphic Associations undefined method 'content'

ruby

ruby-on-rails

undefined

polymorphic-associations

railscasts