Rails如何关联params/从另一个params获取params？

Question

在这个场景中有来自注释的post_id，但是我想从post资源中获得只具有id的后缀，所以注释中的post_id和id来自post是相同的id，所以我尝试将两者关联起来

 def set_post
    @post = Post.find(params[:id])
  end



  def set_comment_post

    @post = Post.find_by(post_id: set_post)
  end

日志显示了错误。

拜托，有人会在这件事上给小费吗？

​

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class PostsController < ApplicationController
  before_action :set_comment_post only: [:comments]


  before_action :set_post, only: [:show, :update, :destroy], except: [:comments]
  before_action :set_user, only: [:show, :update, :destroy, :new]

  # GET /posts
  # GET /posts.json



  def comments

    @comments = @post.comments.order('created_at desc')
    render json: @comments
  end

  # POST /posts
  # POST /posts.json
  def create


    @post = current_user.posts.build(post_params)

    if @post.save

      render json: "Posted successfully", status: 201
    else
      render json: @post.errors, status: :unprocessable_entity
    end
  end

  # PATCH/PUT /posts/1
  # PATCH/PUT /posts/1.json
  def update
    if @post.update(post_params)

      render json: "Posted updated successfully", status: 200
    else
      render json: @post.errors, status: :unprocessable_entity
    end
  end



  private
  def set_user
    @current_user = User.find_by(params[:id])


  end

  # Use callbacks to share common setup or constraints between actions.
  def set_post
    @post = Post.find(params[:id])
  end



  def set_comment_post

    @post = Post.find_by(:post_id => set_post)
  end





  # Never trust parameters from the scary internet, only allow the white list through.
  def post_params
    params.require(:post).permit(:title, :body, :user_id, :posts_count)
  end
end

请求传递的参数

 "/posts/" + this.props.match.params.post_id + "/comments",

Answer 1

还不清楚为什么你需要两个方法来做同样的事情，但我认为你想要的是

仅在多个端点需要before_action时才使用它。另外，不要同时使用[:only]和[:except]这两种方法。这应该是可行的：

class PostsController < ApplicationController
  before_action :set_post, only: [:show, :update, :destroy, :comments]
  before_action :set_user, only: [:show, :update, :destroy, :new]

  def comments
    @comments = @post.comments.order('created_at desc')
    render json: @comments
  end

  def create
    @post = current_user.posts.build(post_params)

    if @post.save
      render json: "Posted successfully", status: 201
    else
      render json: @post.errors, status: :unprocessable_entity
    end
  end

  def update
    if @post.update(post_params)
      render json: "Posted updated successfully", status: 200
    else
      render json: @post.errors, status: :unprocessable_entity
    end
  end

  private
  def set_user
    @current_user = User.find_by(params[:id])
  end

  def set_post
    @post = Post.find(params[:id])
  end

  def post_params
    # add comments attributes if our text field is called 'text'
    params.require(:post).permit(:title, :body, :user_id, :posts_count, comments_attributes: [ :id, :text ] )
  end
end

您还可能需要设置accepts_nested_attributes_for

class Post
  accepts_nested_attributes_for :comments, allow_destroy: true

  has_many :comments, dependent: :destroy
end

然而，您要在前端传递数据，您需要传递带有嵌套字段的post表单，以便进行注释。请参阅helpers.html#nested-forms