Question

我是Rails的初学者，我一直试图解决这个问题好几个小时。我已经搜索并应用了许多解决方案，但没有人能够解决这个问题。

该应用是一个简短的博客，包含文章和评论。我在这个项目中使用scaffold创建了它们，并将它们嵌套在routes.rb中，并在数据库中包含关联。

现在的问题是，评论表单的部分内容根本无法添加任何评论。

评论的部分表格：

 <%= form_with(url: article_comments_path) do |form| %>
  <% 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 |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= form.label :commenter %>
    <%= form.text_field :commenter, id: :comment_commenter %>
  </div>

  <div class="field">
    <%= form.label :body %>
    <%= form.text_field :body, id: :comment_body %>
  </div>


  <div class="actions">
    <%= form.submit %>
  </div>
  <% end %>

文章模型：

class Article < ApplicationRecord
    has_many :comments
    accepts_nested_attributes_for :comments
end

评论模型：

class Comment < ApplicationRecord
  belongs_to :article
end

评论控制员：

def create
  @article = Article.find(params[:article_id])
  @comment = Comment.new(comment_params)
  redirect_to article_path(@article)
  #article_id = params[:article_id]
  #raise params.inspect
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(:commenter, :body)
end

点击提交后，我在评论的表单页面上收到错误：

ActionController::ParameterMissing in CommentsController#create

param is missing or the value is empty: comment Extracted source (around line #437):

#435         value
#436       else
*437         raise ParameterMissing.new(key)
#438       end
#439     end
#440 

Extracted source (around line #73):

#71     # Never trust parameters from the scary internet, only allow the white list through.
#72     def comment_params
*73       params.require(:comment).permit(:commenter, :body)
#74     end
#75 end

Extracted source (around line #36):

#34     
#35     @article = Article.find(params[:article_id])
*36     @comment = @article.comments.create(comment_params)
#37     redirect_to article_path(@article)
#38     
#39   end

的routes.rb

               Prefix Verb   URI Pattern                                       Controller#Action
         rails_admin        /admin                                            RailsAdmin::Engine
    article_comments GET    /articles/:article_id/comments(.:format)          comments#index
                     POST   /articles/:article_id/comments(.:format)          comments#create
 new_article_comment GET    /articles/:article_id/comments/new(.:format)      comments#new
edit_article_comment GET    /articles/:article_id/comments/:id/edit(.:format) comments#edit
     article_comment GET    /articles/:article_id/comments/:id(.:format)      comments#show
                     PATCH  /articles/:article_id/comments/:id(.:format)      comments#update
                     PUT    /articles/:article_id/comments/:id(.:format)      comments#update
                     DELETE /articles/:article_id/comments/:id(.:format)      comments#destroy
            articles GET    /articles(.:format)                               articles#index
                     POST   /articles(.:format)                               articles#create
         new_article GET    /articles/new(.:format)                           articles#new
        edit_article GET    /articles/:id/edit(.:format)                      articles#edit
             article GET    /articles/:id(.:format)                           articles#show
                     PATCH  /articles/:id(.:format)                           articles#update
                     PUT    /articles/:id(.:format)                           articles#update
                     DELETE /articles/:id(.:format)                           articles#destroy

该操作的服务器日志

Started POST "/articles/8/comments" for 127.0.0.1 at 2017-09-02 20:18:44 +0300
Processing by CommentsController#create as JS
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"vy35XCR5S4E7rREcavLifxAPqwzPOrl0bVbbWA4nyXgQDWFLxJYu/2YVa/NdnJGBwN7mCW8RjliPUnkGPtPwnQ==", "commenter"=>"asdasd", "body"=>"sdfdfgdf", "commit"=>"Save ", "article_id"=>"8"}
  [1m[36mArticle Load (5.2ms)[0m  [1m[34mSELECT  "articles".* FROM "articles" WHERE "articles"."id" = $1 LIMIT $2[0m  [["id", 8], ["LIMIT", 1]]
Completed 400 Bad Request in 35ms (ActiveRecord: 5.2ms)



ActionController::ParameterMissing (param is missing or the value is empty: comment):

app/controllers/comments_controller.rb:71:in `comment_params'
app/controllers/comments_controller.rb:33:in `create'

重要提示：

如果我删除 params.require(:comment) 提交将通过＆amp;我将被重定向到正确的页面，但问题是它不会保存评论本身。

请告知我感到迷茫谢谢大家。

Answer 1

您的form_with设置不正确。您需要构建它以使其与模型相关联。

<%= form_with article_comments_path(Comment.new) do |form| %>
    ... parameters here... 
<% end %>

我相信会工作吗？这是关于Medium

的好文章

编辑：

如果你在Articles#Show

，这应该有效

def create
  @article = Article.find(params[:id])
  @comment = @article.comments.create(comment_params)
  redirect_to article_path(@article)
end

这取决于你如何设置路线。

Answer 2

希望这可以帮助其他人，只有两项更改修复了代码：

1-删除comment_params

中的require commment

    def comment_params
      params**.require(:comment)**.permit(:commenter, :body, :article_id)
    end

2-创建操作在发表评论后没有保存

  def create
    @article = Article.find(params[:article_id])
    @comment = Comment.new(comment_params)
    if @comment.save
      redirect_to article_path(@article)
    end  
  end

感谢您的帮助。

在StatementController中提交表单ActionController :: ParameterMissing时出错#create param缺失或值为空：comment

2 个答案: