使用friendly_id时如何find_by_id（用于多态关系）

Jake 发表于 Dev

杰克

我如何允许 find_by_id 工作，以便我的评论可以与我的帖子一起使用friendly_id？有没有其他方法可以做到这一点？

我安装了一个名为 Ruby gemfriendly_id并使用它slugs在我的博客文章中创建。这些博客文章通过polymorphic关系发表评论。我有这些相互矛盾的方法，我认为这是我的评论不起作用并引发错误的原因：

undefined method 'comments' for nil:NilClass

指着@comment = @commentable.comments.new comment_params在创建方法的意见控制器。

在我的评论模型中：

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

在我的评论控制器中：

class CommentsController < ApplicationController
  before_action :find_commentable

  def new
    @comment = Comment.new
  end

  def create
    @comment = @commentable.comments.new comment_params
    if @comment.save
      flash[:success] = "Thanks for sharing your thoughts!"
      redirect_back fallback_location: root_path
    else
      flash[:danger] = "There was an error posting your comment!"
      redirect_back fallback_location: root_path
    end
  end

  private

  def comment_params
    params.require(:comment).permit(:body, :email, :name)
  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

在我的帖子模型中： has_many :comments, as: :commentable

我的路线：

resources :comments do
  resources :comments
end

我的服务器日志：

app/controllers/comments_controller.rb:9:in `create'
Started POST "/posts/top-5-audio-industry-blogs/comments" for 127.0.0.1 at 2018-06-30 10:35:09 -0300
Processing by CommentsController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"[token]", "comment"=>{"body"=>"Hey, thanks for checking out the article! Any questions? Just ask me here and I'll be happy to help.", "name"=>"name", "email"=>"email", "nickname"=>""}, "commit"=>"Post Comment", "post_id"=>"top-5-audio-industry-blogs"}
Post Load (0.0ms)  SELECT  "posts".* FROM "posts" WHERE "posts"."id" = $1 ORDER BY "posts"."created_at" DESC LIMIT $2  [["id", 0], ["LIMIT", 1]]
Completed 500 Internal Server Error in 27ms (ActiveRecord: 6.0ms)



NoMethodError (undefined method `comment' for nil:NilClass):

这是我能想到的唯一导致此错误的原因，因为它在没有 slug 的情况下工作。提前感谢您的任何帮助！

贾格迪普·辛格

根据docs，您需要稍微不同地查询Comment和Post模型，因为帖子有slugs而评论没有。见下文：

def find_commentable
  @commentable = if params[:comment_id]
                   Comment.find_by_id(params[:comment_id])
                 elsif params[:post_id]
                   Post.friendly.find(params[:post_id])
                 end

  # You should also handle the case if `@commentable` is `nil` after above.
  redirect_to somewhere, error: 'Post/Comment not found' unless @commentable
end

本文收集自互联网，转载请注明来源。

如有侵权，请联系 [email protected] 删除。