定期購読のステータスの非同期な確認方法

customer.json

{
  "id": "cus_LG0Lf1WTDaDlbQ",
  "livemode": false,
  "object": "customer",
  "created": 1347547188,
  "description": "1人目の顧客(WebPayスタッフ)",
  "subscription": {
    "object":"subscription",
    "status":"trialing",
    "plan": {
      "id":"curl_plan",
      "object":"plan",
      "amount":1500,
      "currency":"jpy",
      "interval":"year",
      "name":"年間curlプラン",
      "livemode":false,
      "trial_period_days":null
    },
    "ended_at":null,
    "start":1349075131,
    "cancel_at_period_end":false,
    "canceled_at":null,
    "customer":"cus_LG0Lf1WTDaDlbQ",
    "trial_start":1349075131,
    "trial_end":null,
    "current_period_start":1349075131
  },
  "active_card": {
    "object":"card",
    "name":"Kei Kubo",
    "type":"visa",
    "last4":"4242",
    "exp_month":1,
    "exp_year":2014,
    "address_line1":null,
    "address_line2":null,
    "address_city":null,
    "address_state":null,
    "address_country":null,
    "address_zip":null,
    "cvc_check":"pass",
    "address_line1_check":"unchecked",
    "address_zip_check":"unchecked",
    "fingerprint":"a443154aff6e624d4430cd8e5273b6beeabfef88",
    "country":null
  },
  "email": null,
  "account_balance": null,
  "delinquent": null
}