智付通付款 payload 加密

encryption_service.rb

require 'digest/sha2'
require 'base64'
require 'mcrypt'  # 需要 php5-mcrypt libmcrypt-dev libmcrypt 

class EncryptionService
  prepend SimpleCommand   # 可在 rails controller 簡單呼叫這個 library 的 plugin

  def initialize(payload) # 將前台的動態資訊組好後丟進來
    @payload = payload    
  end


  def call
    trade_info = encrypt_trade_info()

    @payload.merge({
      "trade_info": trade_info,
      "trade_sha": trade_sha(trade_info)
    })
  end

  # This is the payload generated from controller as it will come from json post of
  # shopping cart page
  attr_accessor :payload

  private

    # 拿智付通的 key & iv 來加密要付款的內容。
    # 
    def encrypt_trade_info()
      key = Settings.payment.spgateway.key
      iv = Settings.payment.spgateway.iv
      merchantid = Settings.payment.spgateway.merchant_id
      
      # controller 上蒐集到的付款資訊與金額等將會與下面的 hash 整合成一整個 payload
      # 以下可以放在設定檔就放設定檔，但依照智付通的文件好像版本跟語系等等不太需要改(?)
      # 
      @payload = @payload.merge({
        'MerchantID': merchantid,
        'Version': '1.4',
        'RespondType': 'JSON',
        'LangType': 'zh-tw',
        'TradeLimit': '900',
        'ExpireDate': '',
        'ReturnURL': Settings.payment.spgateway.return_url,         # 設定付款完後要把使用者導到哪頁    i.e. https://example.com/payment/spgateway/done
        'NotifyURL': Settings.payment.spgateway.notify_url,         # 設定付款之後背景呼叫完整付款資訊的 end point, i.e. https://example.com/payment/spgateway/notify
        'CustomerURL': Settings.payment.spgateway.customer_url,     # 商店取號網址, 這個我沒用到..直接顯示取號在付款頁面
        'ClientBackURL': Settings.payment.spgateway.client_back_url,
        'EmailModify': Settings.payment.spgateway.email_modify,
        'LoginType': Settings.payment.spgateway.login_type,
        
        # payment methods
        'CREDIT': Settings.payment.spgateway.opt.credit,            # 設定是否啟用信用卡一次付清支付方式。
        'InstFlag': Settings.payment.spgateway.opt.inst_flag,       # 此欄位值=1 時，即代表開啟所有分期期 別，且不可帶入其他期別參數。
        'CreditRed': Settings.payment.spgateway.opt.credit_red,     # 設定是否啟用信用卡紅利支付方式。
        'UNIONPAY': Settings.payment.spgateway.opt.unionpay,        # 設定是否啟用銀聯卡支付方式。
        'WEBATM': Settings.payment.spgateway.opt.webatm,
        'VACC': Settings.payment.spgateway.opt.vacc,
        'CVS': Settings.payment.spgateway.opt.cvs,
        'BARCODE': Settings.payment.spgateway.opt.barcode
      })
      
      # 這個涵式是這邊抄來的: 
      # https://justanothercoder.wordpress.com/2009/04/24/converting-a-hash-to-a-query-string-in-ruby/
      payload_str = Common::hash_to_querystring(@payload)

      # 加密 payload
      crypto = Mcrypt.new(:rijndael_128, :cbc, key, iv, :pkcs)
      ciphertext = crypto.encrypt(payload_str)

      ciphertext.unpack("H*").join()
    end

    def trade_sha(tradeInfo)
      key = Settings.payment.spgateway.key
      iv = Settings.payment.spgateway.iv

      Digest::SHA256.hexdigest("HashKey=#{key}&#{tradeInfo}&HashIV=#{iv}").upcase
    end

end