工作流或 AASM 等 gem 的最佳实践

Question

如果您想更新所有属性，但还需要工作流/AASM 回调正确触发，我想知道你们如何使用控制器中的工作流或 AASM gem。

目前，我是这样使用它的：

  class ModelController < ApplicationController
    def update
      @model = model.find(params[:id])

      if params[:application]['state'].present?
        if params[:application]['state'] == "published"
          @model.publish!
        end
      end
      if @model.update_attributes(params[:application]); ... end
    end
  end

感觉不对，有什么更好的解决方案？

Answer 1

我通常定义多个动作来处理从一种状态到另一种状态的转换，并具有明确的名称。在您的情况下，我建议您添加 publish 操作：

def publish
  # as the comment below states: your action 
  # will have to do some error catching and possibly
  # redirecting; this goes only to illustrate my point
  @story = Story.find(params[:id])
  if @story.may_publish?
    @story.publish!
  else
   # Throw an error as transition is not legal
  end
end

在您的routes.rb 中声明：

resources :stories do
  member do
    put :publish
  end
end

现在您的路线准确地反映了故事发生的情况：/stories/1234/publish

Answer 2

您可以覆盖模型 aasm_state 设置器（或我的示例中的状态），以便它可以接受事件名称。然后我们检查它是否是一个有效的事件，然后检查转换是否有效。如果不是，我们添加正确的错误消息。

请求规范

it "should cancel" do
  put "/api/ampaigns/#{@campaign.id}", {campaign: {status: "cancel"}, format: :json}, valid_session
  response.code.should == "204"
end

模型规范

it "should invoke the cancel method" do
  campaign.update_attribute(:status, "cancel")
  campaign.canceled?.should be_true
end
it "should add an error for illegal transition" do
  campaign.update_attribute(:status, "complete")
  campaign.errors.should include :status
  campaign.errors[:status].should == ["status cannot transition from pending to complete"]
end
it "should add an error for invalid status type" do
  campaign.update_attribute(:status, "foobar")
  campaign.errors.should include :status
  campaign.errors[:status].should == ["status of foobar is not valid.  Legal values are pending, active, canceled, completed"]
end

型号

class Campaign < ActiveRecord::Base
  include AASM
  aasm column: :status do
    state :pending, :initial => true
    state :active
    state :canceled
    state :completed
    # Events
    event :activate do
      transitions from: :pending, to: :active
    end
    event :complete do
      transitions from: :active, to: [:completed]
    end
    event :cancel do
      transitions from: [:pending, :active], to: :canceled
    end
  end
  def status=(value)
    if self.class.method_defined?(value)
      if self.send("may_#{value}?")
        self.send(value)
      else
        errors.add(:status, "status cannot transition from #{status} to #{value}")
      end

    else
      errors.add(:status, "status of #{value} is not valid.  Legal values are #{aasm.states.map(&:name).join(", ")}")
    end
  end
end

Answer 3

这是一件小事，但如果该事物不存在，则哈希返回 nil，因此您可以删除对 present 的调用？

我知道这当然不是你要问的。一种替代方法是在模型中放置一个前置过滤器并在那里检查状态。这会使您的控制器对您的状态的底层存储视而不见。

顺便说一句，我们在这里使用 AASM，我喜欢它 :)

Answer 4

我希望我的模型在更新后返回新状态，这是我能想到的最简单的方法，而控制器中没有太多“脂肪”，而且如果你的工作流程发生变化，它会让你更容易前进：

class Article < ActiveRecord::Base
  include Workflow
  attr_accessible :workflow_state, :workflow_event # etc
  validates_inclusion_of :workflow_event, in: %w(submit approve reject), allow_nil: true
  after_validation :send_workflow_event

  def workflow_event
    @workflow_event
  end

  def workflow_event=(workflow_event)
    @workflow_event = workflow_event
  end

  # this method should be private, normally, but I wanted to 
  # group the meaningful code together for this example
  def send_workflow_event
    if @workflow_event && self.send("can_#{@workflow_event}?")
      self.send("#{@worklow_event}!")
    end
  end

  # I pulled this from the workflow website, to use that example instead.
  workflow do
    state :new do
      event :submit, :transitions_to => :awaiting_review
    end
    state :awaiting_review do
      event :review, :transitions_to => :being_reviewed
    end
    state :being_reviewed do
      event :accept, :transitions_to => :accepted
      event :reject, :transitions_to => :rejected
    end
    state :accepted
    state :rejected
  end
end