Ruby-on-rails 参数缺失或值为空：ResultController#update 中的 ParameterMissing
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Param is missing or the value is empty: ParameterMissing in ResultsController#update
提问by user2926430
I have a Result that belongs to a Website. After I create the website I also create the result and redirect to its edit page. Here I want to add some more values.
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。
My problem is: When I try to update my Result, then I get:
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"}
This is how my Result params looks like
这就是我的结果参数的样子
def result_params
params.require(:result).permit(:data)
end
My model:
我的型号：
class Result < ActiveRecord::Base
belongs_to :website
attr_accessor :website_id
attr_accessor :data
serialize :data, Array
end
Here is my controller code:
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
My view:
我的看法：
<%= 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 %>
And this is the place where i call the edit result page:
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
Ive allready tryed every solution I could find, but none of them seemed to work for me.
我已经尝试了我能找到的所有解决方案，但似乎没有一个对我有用。
回答by Nitish Parkar
The problem lies here:
问题出在这里：
params.require(:result).permit(:data)
From requiredocumentation,
从需要文档，
require ensures that a parameter is present. If it's present, returns the parameter at the given key, otherwise raises an ActionController::ParameterMissing error.
require 确保存在参数。如果存在，则返回给定键处的参数，否则引发 ActionController::ParameterMissing 错误。
You are requiring resultparameter but it's missing from the params. All your values are inside dataparam. Removing require should do the trick.
您需要result参数，但参数中缺少它。你所有的值都在data参数里面。删除 require 应该可以解决问题。
params.permit(:data)
If you want to keep require, wrap datainside resultin forms.
如果您想保留要求，请用表格包裹data在里面result。
回答by TorvaldsDB
I know, what you met. if you strong params is
我知道，你遇到了什么。如果你强大的参数是
def result_params
params.require(:result).permit(:data)
end
Your parameters should has the format like this
你的参数应该有这样的格式
Parameters: {"result"=>{"data"=>"string"}}
and your parameters is just
你的参数只是
Parameters: {"data"=>"string"}
so you should remove the "result"
所以你应该删除“结果”
回答by Hymantrades
This error also occurs if you try to have a form submit without any fields. If you just want the single value you're passing through a button param you can use a hidden_field as a work around.
如果您尝试提交没有任何字段的表单，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，您可以使用 hidden_field 作为解决方法。
