expires_date field is invalid for auto-renewable subscriptions

[gmcnaughton]

When I verify receipts for auto-renewable subscriptions, the value for expires_date is wrong:

receipt_data = "..." # receipt for auto-renewable subscription
receipt = Itunes::Receipt.verify!(receipt_data, true)
receipt.expires_date
# => "1969-12-31 16:00:02.000000000 -08:00" (UTC epoch + 2 seconds?)

I think Receipt#initialize is parsing expires_date as milliseconds, but Apple's validator returns it as three fields (date, date_ms, and date_pst), similar to how it returns purchase_date. Snippet of a raw response from the validator:

{
  "receipt": {
    "in_app": [
      {
        ...,
        "purchase_date": "2015-08-01 11:47:43 Etc/GMT",
        "purchase_date_ms": "1438429663000",
        "purchase_date_pst": "2015-08-01 04:47:43 America/Los_Angeles",
        "expires_date": "2015-09-01 11:47:43 Etc/GMT",
        "expires_date_ms": "1441108063000",
        "expires_date_pst": "2015-09-01 04:47:43 America/Los_Angeles",

It looks like at some point Apple standardized how they return their date fields, but expires_date is being parsed as ms instead of a date string.

[svendvd]

Works perfekt, Thx! Please merge it!

gem 'itunes-receipt', :git => 'https://github.com/curious/itunes-receipt.git', :branch => 'autorenew-cancellation_date'

[Paludis]

+1 merge please