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Ruby AASM使用

: Ruby

AASM，是一個狀態管理的gem，可以更好的幫助你管理各種在不同時間的不同狀態。 首先在Gemfile安裝 gem 'aasm' 在要使用的model裡include，在此要記住model要有一個欄位為名為aasm_state好方便記住狀態。

class Order < ApplicationRecord
	include AASM
  aasm do
    state :order_placed, initial: true #初始化
    state :paid
    state :shipping
    state :shipped
    state :order_cancelled
    state :good_returned
    event :make_payment, after_commit: :pay! do
      transitions from: :order_placed, to: :paid
    end
    event :ship do
      transitions from: :paid, to: :shipping
    end
    event :deliver do
      transitions from: :shipping, to: :shipped
    end
    event :return_good do
      transitions from: :shipped, to: :good_returned
    end
    event :cancel_order do
      transitions from: [:order_placed, :paid], to: :order_cancelled
    end
  end
end


state :order_placed, initial: true


上面這段解釋為
state 為可能性狀態
initial 為一開始的初始狀態(model 一建立之後) 

event :make_payment, after_commit: :pay! do
	transitions from: :order_placed, to: :paid
end


event 表示為各個事件method名稱
transitions from: 什麼狀態改為 to: 狀態
after_commit 表示説如果make_payment為true就執行 pay! 的Method(在此沒顯示出來)
請使用Rails 環境執行rails c 

order = Order.new
order.order_placed? # true
order
#<Order:0x00123443asd> {
            :aasm_state => "order_placed",
}
order.make_payment # true
order
#<Order:0x00123443asd> {
            :aasm_state => "paid",
}
order.ship # true
order
#<Order:0x00123443asd> {
            :aasm_state => "shipping",
}


以上為使用方式以此類推
transitions from: 也可以是一個Array，但如果呼叫了此event但狀態不包含在from裡面則會發錯誤！
aasm do預設執會去找aasm_state這個欄位，如要設定哪個欄位請使用aasm(:your column) do

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