Question

我有一个属于网站的结果。创建网站后，我还创建了结果并重定向到其编辑页面。在这里，我想添加一些更多的值。

我的问题是：当我尝试更新我的结果时，我得到：

param is missing or the value is empty: result


    Request

    Parameters:

    {"utf8"=>"✓",  "_method"=>"patch",  "authenticity_token"=>"GRN/y/04Qbsm9DzlUAbUYF8ZSv2EMHnRZgBZY/6GMDlOBdq8V5Uncij9VRp51uydC6M/qc61jPWwpUehSuc5xA==", "data"=>["//html/body/div[position() = 3]/ul/li[position() = 16]/ul/li[position() = 2]/child::text()",  "//html/body/div[position()
    = 3]/ul/li[position() = 16]/ul/li[position() = 2]/p/a/child::text()",  "//html/body/div[position() = 3]/ul/li[position() = 16]/ul/li[position() = 4]/child::text()",  "//html/body/div[position()
    = 3]/ul/li[position() = 16]/ul/li[position() = 5]/a/child::text()"],  "commit"=>"Update Result",  "id"=>"66"}

这就是我的结果参数的样子

def result_params
      params.require(:result).permit(:data)
    end

我的模特：

class Result < ActiveRecord::Base
  belongs_to :website
  attr_accessor :website_id
  attr_accessor :data

  serialize :data, Array
end

这是我的控制器代码：

    class ResultsController < ApplicationController
  before_action :set_result, only: [:show, :edit, :update, :destroy]

  # GET /Results
  # GET /Results.json
  def index
    @results = Result.all
  end

  # GET /Results/1
  # GET /Results/1.json
  def show
  end

  # GET /Results/new
  def new
    @result = Result.new
  end

  # GET /Results/1/edit
  def edit
    @result = Result.find(params[:id])
  end

  # POST /Results
  # POST /Results.json
  def create
    @result = Result.new(result_params)

    respond_to do |format|
      if @result.save
        format.html { redirect_to @result, notice: 'Result was successfully created.' }
        format.json { render :show, status: :created, location: result }
      else
        format.html { render :new }
        format.json { render json: @result.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /Results/1
  # PATCH/PUT /Results/1.json
  def update
    respond_to do |format|
      if @result.update(result_params )
        format.html { redirect_to @result, notice: 'Result was successfully updated.' }
        format.json { render :show, status: :ok, location: @result }
      else
        format.html { render :edit }
        format.json { render json: @result.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /Results/1
  # DELETE /Results/1.json
  def destroy
    @result.destroy
    respond_to do |format|
      format.html { redirect_to results_url, notice: 'Result was successfully destroyed.' }
      format.json { head :no_content }
    end
  end


  private
    # Use callbacks to share common setup or constraints between actions.
    def set_result
      @result = Result.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def result_params
      params.permit(:data => [])
    end
end

我的观点：

<%= form_for(@result) do |f| %>
  <% if @result.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@result.errors.count, "error") %> prohibited this result from being saved:</h2>

      <ul>
      <% @result.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>


    <div class="field">
      <% if @result.website.url != nil %>
      <%= atts = get_all_elements(@result.website.url)%>
          <% atts.each do |p| %>
              <div>
                <%= check_box_tag "data[]", get_xpath_from_node(p)%>
                <%= p.text %>
              </div>
          <%end%>
      <% end%>
    </div>

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

这是我调用编辑结果页面的地方：

def update
    respond_to do |format|
      if @website.update(website_params)
        format.html { redirect_to @website, notice: 'Website was successfully updated.' }
        format.json { render :show, status: :ok, location: @website }
      else
        format.html { render :edit }
        format.json { render json: @website.errors, status: :unprocessable_entity }
      end
    end
  end

我已经尝试过我能找到的所有解决方案，但它们似乎都不适合我。

Answer 1

问题在于：

params.require(:result).permit(:data)

来自require文档，

require确保存在参数。如果它存在，则返回给定键的参数，否则引发一个 ActionController :: ParameterMissing错误。

您需要result参数，但参数中缺少该参数。您的所有值都在data param内。删除require应该可以解决问题。

params.permit(:data)

如果您想保留要求，请在表格中data内包裹result。

Answer 2

我知道，你遇到了什么。如果你强大的params是

def result_params
  params.require(:result).permit(:data)
end

您的参数应具有此类格式

Parameters: {"result"=>{"data"=>"string"}}

，你的参数只是

Parameters: {"data"=>"string"}

所以你应该删除＆＃34;结果＆＃34;

Answer 3

如果您尝试在没有任何字段的情况下提交表单，也会发生此错误。如果您只想要通过按钮参数传递的单个值，则可以使用hidden_field作为解决方法。

Param丢失或值为空：ResultsController＃update中的ParameterMissing

3 个答案: