Question

我是Ruby on Rails的新手，我正在与我的脚手架控制器挣扎。我创建了一个嵌套资源，我的评论放在帖子中。

class Post < ActiveRecord::Base
  validates :name,  :presence => true
  validates :title, :presence => true, :length => { :minimum => 5 }
  has_many :comments
end

class Comment < ActiveRecord::Base
  validates :commenter, :presence => true
  validates :body, :presence => true     
  belongs_to :post
end

控制器的简化版本是

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

  # omited new, index, show... 

  # POST /comments
  # POST /comments.json
  def create
    post = Post.find(params[:post_id])
    @comment = post.comments.create(params[:comment].permit(:name, :title, :context))

    respond_to do |format|
      if @comment.save
        format.html { redirect_to([@comment.post, @comment], 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
    post = Post.find(params[:post_id])
    @comment = post.comments.find(params[:comment])
    respond_to do |format|
      if @comment.update(comment_params)
        format.html { redirect_to @comment, 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

  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, :post)
    end
end

当我填写表格时，我得到了这个例外：

2个错误禁止保存此评论：评论者不能空白身体不能空白

我尝试了this指南，但我认为它与Rails 4不是100％兼容。

Answer 1

您的permitting操作中明显显示create个不同的属性集。

您应该像create行动一样更新comment_params行动以使用update。您Comment的原因绝对是您Commenter行动中允许的Body和:name, :title, :context而非create。

将controller的{{1}}动作更新为：

create

Answer 2

您正在阅读params（Post）的:name, :title, :context属性，但您需要阅读Comments属性（:commenter, :body）

替换这个：

@comment = post.comments.create(params[:comment].permit(:name, :title, :context))

带

@comment = post.comments.create(params[:comment].permit(:commenter, :body))

或更好的是：

@comment = post.comments.create(comment_params)

Rails形成没有被保存的参数

2 个答案: