Rails 5 + Ajax：仅在注释存在时附加注释

我正在尝试创建一个function，用户可以使用Ajax创建对文章的评论。 但是，我无法理解为什么只有一条评论存在才能通过ajax成功呈现评论。 注释将提交到数据库而不进行任何回滚。

如果我重新加载页面并创建第二条评论，则只会附加新评论。

Started POST "/articles/veniam-ipsum-eos-quas-aut-rerum-consequatur-at-velit-perferendis-odio/comments" for 103.252.202.198 at 2017-11-03 16:50:14 +0000 Processing by CommentsController#create as JS Parameters: {"utf8"=>"✓", "comment"=>{"content"=>"comment only appended if a comment exists"}, "commit"=>"Add Comment", "article_id"=>"veniam-ipsum-eos-quas-aut-rerum-consequatur-at-velit-perferendis-odio"} User Load (0.4ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2 [["id", 1], ["LIMIT", 1]] Article Load (0.6ms) SELECT "articles".* FROM "articles" WHERE "articles"."slug" = $1 LIMIT $2 [["slug", "veniam-ipsum-eos-quas-aut-rerum-consequatur-at-velit-perferendis-odio"], ["LIMIT", 1]] (0.2ms) BEGIN SQL (0.6ms) INSERT INTO "comments" ("content", "article_id", "user_id", "created_at", "updated_at") VALUES ($1, $2, $3, $4, $5) RETURNING "id" [["content", "comment only appended if a comment exists"], ["article_id", 189], ["user_id", 1], ["created_at", "2017-11-03 16:50:14.291049"], ["updated_at", "2017-11-03 16:50:14.291049"]] (2.5ms) COMMIT 

评论控制器

 class CommentsController < ApplicationController before_action :authenticate_user! before_action :set_article def create @comment = @article.comments.build(comment_params) @comment.user = current_user if @comment.save respond_to do |format| format.html do flash[:success] = "Your comment was created successfully" redirect_to @comment.article end format.js end unless @comment.article.user == current_user Notification.create!(recipient: @article.user, actor: current_user, action: "posted", notifiable: @comment) end else respond_to do |format| format.html { redirect_to @comment.article, flash[:error] = "Unable to submit comment."} end end end private def set_article @article = Article.friendly.find(params[:article_id]) end def comment_params params.require(:comment).permit(:content) end end 

文章控制器

  def show @comments = @article.comments.order("created_at DESC") @new_comment = @article.comments.new end 

文章/ show.html.erb

    
  
  
 
 There are no comments yet.
 
  

评论/ _comment_form.html.erb

评论/ _comment.html.erb

评论/ create.js.erb

 $('#comment').append(""); 

路线：

  resources :articles do resources :comments end 

解：

用户PlanB在下面提供了一个有效的解决方案，但我稍微调整了一下答案，以便

There are no comments yet.

在提交评论表后删除。

文章/ show.html.erb

  
  
 
    
 
 There are no comments yet.
 
   

评论/ create.js.erb

 $('#comment-list').append(""); $('#no-comments p').html(''); 

Answer 1

尝试以下方法：

  <%= render 'comments/comment_form' %> <% if @comments.exists? %> 
 <%= render @comments %> 
 <% else %> 
 
 There are no comments yet.
 
 <% end %> 

和：

 $('.comment').append("<%= escape_javascript (render partial: @comment) %>"); 

因为if现在有注释，你的if语句不会创建div#comment ，所以

$('#comment').append("<%= escape_javascript (render partial: @comment) %>"); 不能将任何内容附加到#comment因为它不存在于HTML中。

Answer 2

我相信问题出在你的create方法中。 由于您已重定向到@comment.article ，因此无法再访问create.js.erb。 尝试重写create方法，如下所示：

 def create @comment = @article.comments.build(comment_params) @comment.user = current_user if @comment.save respond_to do |format| format.html do flash[:success] = "Your comment was created successfully" end format.js end unless @comment.article.user == current_user Notification.create!(recipient: @article.user, actor: current_user, action: "posted", notifiable: @comment) end else respond_to do |format| format.html { redirect_to @comment.article, flash[:error] = "Unable to submit comment."} end end end