Rails 4 with Pundit & Statesman gem - 对象处于状态时的策略

Posted 2023-04-13

【中文标题】Rails 4 with Pundit & Statesman gem - 对象处于状态时的策略

【英文标题】：Rails 4 with Pundit & Statesman gem - policy when an object is in a state

【发布时间】：2016-01-29 00:24:13

【问题描述】：

我正在尝试在 Rails 4 中制作应用程序。

我正在尝试将 statesman gem 用于状态，然后将 pundit 用于政策。

我的 gemfile 有：

gem 'statesman', '~> 1.3', '>= 1.3.1'
gem 'pundit'

我有一个文章模型、一个文章转换模型和一个 article_state_machine 模型。

我的目标是在我的文章策略中定义一个发布策略（使用权威人士），它允许拥有文章的用户在文章处于“已批准”状态时发布该文章。

我正在我的权威文章政策中尝试这样做：

class ArticlePolicy < ApplicationPolicy

def publish?

user.present? && user == article.user 
# if requires approval, then approved

# and article.in_state(:approve) - why doesnt this work - see statesman docs? 

 # user && user.article.exists?(article.id)

 end
end

当我尝试检查文章是否处于 :approve 状态（如上所述）时，我收到一条错误消息，显示未定义方法“in_state”。

如何在策略中使用状态机？还是该策略允许用户随时发布，但您仅在文章处于批准状态时才在文章显示页面上显示按钮（尽管我认为这是专家的观点）。

文章.rb

class Article < ActiveRecord::Base
  include Statesman::Adapters::ActiveRecordQueries
has_many :transitions, class_name: "ArticleTransition", autosave: false  
def state_machine
    @state_machine ||= ArticleStateMachine.new(self, transition_class: ArticleTransition, association_name: :transitions)
  end

  # delegate :can_transition_to?. :trans

  # def reindex_articles
  #   article.reindex_async
  # end

  private

  def self.transition_name
    :transitions
  end

  def self.transition_class
    ArticleTransition
  end

  def self.initial_state
    # ArticleTransition.initial_state
    :draft
  end
end

文章状态机模型：

class ArticleStateMachine
    include Statesman::Machine

  state :draft, initial: :true #while author is drafting
  state :review #while approver comments are being addressed (really still in draft)
  state :reject # not suitable for publication
  state :approve # suitable for publication
  state :publish #published
  state :remove #  destroyed
  # state :spotlight

  transition from: :draft, to: [:reject, :approve, :publish, :remove]
  # transition from: :review, to: [:rejected, :approved, :removed]
  transition from: :reject, to: [:draft, :remove]
  transition from: :approve, to: [:publish, :remove]
  transition from: :publish, to: :remove

end

文章过渡模型：

class ArticleTransition < ActiveRecord::Base
  include Statesman::Adapters::ActiveRecordTransition


  belongs_to :article, inverse_of: :article_transitions



end

文章控制器：

  def approve
    article = Article.find(params[:id])
    if article.state_machine.transition_to!(:approve)
      flash[:notice] = "This article has been approved for publication"
      redirect_to action: :show, id: article_id
      # add mailer to send message to article owner that article has been approved
    else
      flash[:error] = "You're not able to approve this article"
      redirect_to action: :show, id: article_id
    end
  end

def publish
    article = Article.find(params[:id])
    authorize @article

    if article.state_machine.transition_to!(:publish)
      redirect_to action: :show, id: article_id
      # how do you catch the date the state became published?
    else
      flash[:error] = "You're not able to publish this article"
      redirect_to action: :show, id: article_id
    end
  end

谁能看到我做错了什么？

整个文章控制器有：

class ArticlesController < ApplicationController
  before_action :set_article, only: [:show, :edit, :update, :destroy, :reject, :approve, :publish, :remove]
  before_action :authenticate_user!, except: [:index, :show, :search, :reject, :approve, :publish, :remove]


  respond_to :html, :json
# GET /articles
  # GET /articles.json
  def index
    @articles = policy_scope(Article)
    # query = params[:query].presence || "*"
    # @articles = Article.search(query)
  end

  # def index
  #   if params[:query].present?
  #     @books = Book.search(params[:query], page: params[:page])
  #   else
  #     @books = Book.all.page params[:page]
  #   end
  # end

  # GET /articles/1
  # GET /articles/1.json
  def show

  end

  # GET /articles/new
  def new
    @article = Article.new
    @article.comments.build
  end

  # GET /articles/1/edit
  def edit

    authorize @article
  end

  # POST /articles
  # POST /articles.json
  def create
    # before_action :authenticate_user!
    # authorize @article
    @article = current_user.articles.new(article_params)

    respond_to do |format|
      if @article.save
        format.html  redirect_to(@article) 
        format.json  render :show, status: :created, location: @article 
      else
        format.html  render :new 
        format.json  render json: @article.errors, status: :unprocessable_entity 
      end
    end
  end

  def search
    if params[:search].present?
      @articless = Article.search(params[:search])
    else 
      @articles = Articles.all
    end
  end


  # PATCH/PUT /articles/1
  # PATCH/PUT /articles/1.json
  def update
    # before_action :authenticate_user!
    authorize @article
    respond_to do |format|
    #   if @article.update(article_params)
    #     format.json  render :show, status: :ok, location: @article 
    #   else
    #     format.html  render :edit 
    #     format.json  render json: @article.errors, status: :unprocessable_entity 
    #   end
    # end
      if @article.update(article_params)
         format.html  redirect_to(@article) 
        format.json  render :show, status: :ok, location: @article 
      else
        format.json  render json: @article.errors, status:      :unprocessable_entity 
      end
      format.html  render :edit 
    end
  end



  # DELETE /articles/1
  # DELETE /articles/1.json
  def destroy
    before_action :authenticate_user!
    authorize @article
    @article.destroy
    respond_to do |format|
      format.json  head :no_content 
    end
  end

  # def review
  #   article = Article.find(params[:id])
  #   if article.state_machine.transition_to!(:review)
  #     flash[:notice] = "Comments on this article have been made for your review"
  #     redirect_to action: :show, id: article_id
  #   else
  #     flash[:error] = "You're not able to review this article"
  #     redirect_to action: :show, id: article_id
  #   end
  # end

  def reject
  end

  def approve
    article = Article.find(params[:id])
    if article.state_machine.transition_to!(:approve)
      flash[:notice] = "This article has been approved for publication"
      redirect_to action: :show, id: article_id
      # add mailer to send message to article owner that article has been approved
    else
      flash[:error] = "You're not able to approve this article"
      redirect_to action: :show, id: article_id
    end
  end

  def publish
    article = Article.find(params[:id])
    if article.state_machine.transition_to!(:publish)
      redirect_to action: :show, id: article_id
      # how do you catch the date the state became published?
    else
      flash[:error] = "You're not able to publish this article"
      redirect_to action: :show, id: article_id
    end
  end

  def remove
    article = Article.find(params[:id])
    if article.state_machine.transition_to!(:remove)
      redirect_to root_path
    else
      flash[:error] = "You're not able to destroy this article"
      redirect_to action: :show, id: article_id
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_article
      @article = Article.find(params[:id])
      authorize @article
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def article_params
      params.require(:article).permit(:body, :title, :image, :tag_list,
        comment_attributes: [:opinion])
    end

end

【问题讨论】：

你在哪里打电话给 Pundit 的 authorize？

好点。当我将 authorise@article 添加到发布操作时，我收到一条错误消息：Statementsman::TransitionFailedError in ArticlesController#publish 无法从“发布”转换为“发布”

那么看来 Pundit 方面没有问题。原因应该在异常消息/堆栈跟踪中的某个地方。顺便说一句，bang 方法transition_to! 引发异常而不是返回false。如果您不打算捕获这些异常，最好使用非爆炸方法并打印相应的错误消息（无论如何，对程序流使用异常并不是一个好主意）。

日志中的错误说： Completed 500 Internal Server Error in 5ms (ActiveRecord: 0.8ms) NoMethodError (undefined method in_state?' for #<ArticleStateMachine:0x007ff37ff65098>): app/policies/article_policy.rb:51:in publish?' app/controllers/articles_controller.rb:157:in ` set_article'

您能否将代码更新到与出现该错误的版本完全相同的版本？如果能看到全貌就更好了。

【参考方案1】：

您正在使用的 statesman gem 版本没有定义 in_state?。您可以更新宝石。或者您可以使用 smallbuttoncom 链接的类似代码自己定义它

https://github.com/gocardless/statesman/blob/1fd4ee84c87765b7855688b8eb5dddea7ddddbdd/lib/statesman/machine.rb#L180-L182

但是，对于您的情况，一个简单的检查就足够了。在您的政策中尝试以下代码

article.state_machine.current_state == "approve"

希望对您有所帮助。

【参考方案2】：

当我尝试检查文章是否处于状态时：批准（如评论 上面），我收到一条错误消息，上面写着未定义的方法 'in_state'。

您是否尝试在您的政策中将 article.in_state?(:approve) 更改为 article.state_machine.in_state?(:approve)？

【讨论】：

好点 Guilherme，我试过了，但它给出了这个错误：NoMethodError in ArticlesController#publish undefined method `in_state' for #<0x007ff3642a8ca8>

<0x007ff37ea21f10>

【参考方案3】：

您错过了方法末尾的?：

in_state 方法实际上是一个类方法，其行为类似于作用域。

你需要使用in_state?方法，它是一个实例方法，像这样：

article.state_machine.in_state?(:approve)