如何允许具有强参数的数组

我有一个正常运行的Rails 3应用程序使用has_many:通过关联不是,因为我作为一个Rails 4应用程序重新制作,让我从Rails 4版本的相关模型中保存id。

这两个版本的三个相关模型是相同的。

Categorization.rb

class Categorization < ActiveRecord::Base belongs_to :question belongs_to :category end 

Question.rb

 has_many :categorizations has_many :categories, through: :categorizations 

Category.rb

 has_many :categorizations has_many :questions, through: :categorizations 

在这两个应用程序中,类别ID都会像这样传递到创build操作中

  "question"=>{"question_content"=>"How do you spell car?", "question_details"=>"blah ", "category_ids"=>["", "2"], 

在Rails 3应用程序中,当我创build一个新问题时,它会插入到问题表中,然后插入到分类表中

  SQL (82.1ms) INSERT INTO "questions" ("accepted_answer_id", "city", "created_at", "details", "province", "province_id", "question", "updated_at", "user_id") VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?) [["accepted_answer_id", nil], ["city", "dd"], ["created_at", Tue, 14 May 2013 17:10:25 UTC +00:00], ["details", "greyound?"], ["province", nil], ["province_id", 2], ["question", "Whos' the biggest dog in the world"], ["updated_at", Tue, 14 May 2013 17:10:25 UTC +00:00], ["user_id", 53]] SQL (0.4ms) INSERT INTO "categorizations" ("category_id", "created_at", "question_id", "updated_at") VALUES (?, ?, ?, ?) [["category_id", 2], ["created_at", Tue, 14 May 2013 17:10:25 UTC +00:00], ["question_id", 66], ["updated_at", Tue, 14 May 2013 17:10:25 UTC +00:00]] 

在rails 4应用程序中,在处理QuestionController#create中的参数之后,我在服务器日志中得到这个错误

 Unpermitted parameters: category_ids 

问题只是插入到问题表中

  (0.2ms) BEGIN SQL (67.6ms) INSERT INTO "questions" ("city", "created_at", "province_id", "question_content", "question_details", "updated_at", "user_id") VALUES ($1, $2, $3, $4, $5, $6, $7) RETURNING "id" [["city", "dd"], ["created_at", Tue, 14 May 2013 17:17:53 UTC +00:00], ["province_id", 3], ["question_content", "How's your car?"], ["question_details", "is it runnign"], ["updated_at", Tue, 14 May 2013 17:17:53 UTC +00:00], ["user_id", 12]] (31.9ms) COMMIT 

虽然我没有将类别标识存储在问题模型中,但我在类别标识中设置了许多参数

  def question_params params.require(:question).permit(:question_details, :question_content, :user_id, :accepted_answer_id, :province_id, :city, :category_ids) end 

任何人都可以解释我应该如何保存category_ids? 请注意,任何应用程序的categories_controller.rb中都没有创build操作。

这两个应用程序中的三个表是相同的

  create_table "questions", force: true do |t| t.text "question_details" t.string "question_content" t.integer "user_id" t.integer "accepted_answer_id" t.datetime "created_at" t.datetime "updated_at" t.integer "province_id" t.string "city" end create_table "categories", force: true do |t| t.string "name" t.datetime "created_at" t.datetime "updated_at" end create_table "categorizations", force: true do |t| t.integer "category_id" t.integer "question_id" t.datetime "created_at" t.datetime "updated_at" end 

更新

这是来自Rails 3应用程序的创build操作

  def create @question = Question.new(params[:question]) respond_to do |format| if @question.save format.html { redirect_to @question, notice: 'Question was successfully created.' } format.json { render json: @question, status: :created, location: @question } else format.html { render action: "new" } format.json { render json: @question.errors, status: :unprocessable_entity } end end end 

这是来自Rails 4应用程序的创build操作

  def create @question = Question.new(question_params) respond_to do |format| if @question.save format.html { redirect_to @question, notice: 'Question was successfully created.' } format.json { render json: @question, status: :created, location: @question } else format.html { render action: "new" } format.json { render json: @question.errors, status: :unprocessable_entity } end end end 

这是question_params方法

  private def question_params params.require(:question).permit(:question_details, :question_content, :user_id, :accepted_answer_id, :province_id, :city, :category_ids) end 

这个https://github.com/rails/strong_parameters看起来像文档的相关部分:;

允许的标量types是String,Symbol,NilClass,Numeric,TrueClass,FalseClass,Date,Time,DateTime,StringIO,IO,ActionDispatch :: Http :: UploadedFile和Rack :: Test :: UploadedFile。

要声明参数中的值必须是允许的标量值的数组,则将该键映射到空数组:

 params.permit(:id => []) 

在我的应用程序中,category_ids被传递给数组中的create动作

 "category_ids"=>["", "2"], 

因此,在声明强参数时,我明确地将category_ids设置为一个数组

 params.require(:question).permit(:question_details, :question_content, :user_id, :accepted_answer_id, :province_id, :city, :category_ids => []) 

现在完美的工作!

如果你想允许一个散列数组(或从JSONangular度来看是an array of objects

 params.permit(:foo, array: [:key1, :key2]) 

这里要注意2点:

  1. array应该是permit方法的最后一个参数。
  2. 你应该在数组中指定哈希键,否则你会得到一个错误Unpermitted parameter: array ,在这种情况下非常难以debugging。

应该是这样的

 params.permit(:id => []) 

重要*必须放在最后。 第一个和第二个答案让我知道了。

如果你有这样的哈希结构:

 Parameters: {"link"=>{"title"=>"Something", "time_span"=>[{"start"=>"2017-05-06T16:00:00.000Z", "end"=>"2017-05-06T17:00:00.000Z"}]}} 

那么这就是我如何工作:

 params.require(:link).permit(:title, time_span: [[:start, :end]])