ROR：工作流gem：我想从数据库实现动态状态

Question

我目前正在从事一个必须实施动态工作流的项目。

Dynamic: I store workflow's states in database table called wf_steps and the workflow gem has to create states for a particular workflow from the database

为此，我正在尝试使用 workflow gem。您可以在 gem 的 github 页面中看到它如何初始化状态和相应的事件。

我的代码：

class SpsWorkflow < ActiveRecord::Base
  belongs_to :user
  has_many :wf_steps
  include Workflow
  workflow do
    # binding.pry
    # read wf-states from the database
    # for now let event be same for all the states
    self.wf_steps.each do |step|
      state step.title.to_sym do
        event :assign, transitions_to: :assigning
        event :hire, transitions_to: :hiring
        event :not_hire, transitions_to: :not_hiring
      end
    end
  end
end

期望和遇到的问题：

我预计在代码块中术语 self.wf_steps 会 return 我的 SpsWorkflow 的 instance/collection。但是 self 关键字 returns #<Workflow::Specification:0x000000063e23e8 @meta={}, @states={}> 当我在 workflow 方法块中使用 binding.pry 时（我在代码中注释）

# read wf-states from the database
# for now let event be same for all the states
  self.wf_steps.each do |step|
    state step.title.to_sym do

需要你的帮助，谢谢

编辑：我还尝试将实例存储在一个变量中，并在传递给 workflow 方法调用的块中使用该变量。

class SpsWorkflow < ActiveRecord::Base
  include Workflow
  sps_instance = self

但是我得到了 class SpsWorkflow 的实例

SpsWorkflow(id: integer, workflow_state: string, assigned_to: integer, title: string, description: string, organization_id: integer, user_id: integer, created_at: datetime, updated_at: datetime)

但我想要

 #<SpsWorkflow id: 1, workflow_state: "step1", assigned_to: nil, title: "Software Engineer", description: "Hire best engineer", organization_id: nil, user_id: 1, created_at: "2015-08-08 00:58:12", updated_at: "2015-08-08 00:58:12">

Answer 1

您使用过：

workflow do
  self.something
end

self 在此块的上下文中将引用 WorkflowSpecification。如果你真的想访问 SpsWorkflow 的实例，你可能必须将它传递到块中或将它分配给不同的变量并在那里使用它。

Answer 2

我终于用activerecord回调解决了

class SpsWorkflow < ActiveRecord::Base
  include Workflow
  after_initialize do
    sps_instance = self
    SpsWorkflow.workflow do
      # read wf-states as well as events from the database
      sps_instance.wf_steps.each do |step|
        state step.title.to_sym do
          event :assign, transitions_to: :step2
          event :hire, transitions_to: :hire
          event :not_hire, transitions_to: :not_hiring
        end
      end
    end
  end
  belongs_to :user
  has_many :wf_steps
end

ROR：工作流gem：我想从数据库实现动态状态

ROR : Workflow gem : I want to implement dynamic states from database

ruby

workflow

metaprogramming

ruby-on-rails