我遇到了 Paypal 定期付款的问题。CreateRecurringPaymentsProfile() 返回已创建配置文件的 ID (ProfileID)。同时，我在 IPN url 上收到以下确认：
payment_cycle - Daily
txn_type - recurring_payment_profile_
created
last_name - User
next_payment_date - 03:00:00 Oct 06, 2011 PDT
residence_country - US
initial_payment_amount - 0.00
currency_code - USD
time_created - 23:21:02 Oct 05, 2011 PDT
verify_sign - ...
period_type - Regular
payer_status - verified
test_ipn - 1
tax - 0.00
payer_email - ...
first_name - Test
receiver_email - ...
payer_id - ...
product_type - 1
shipping - 0.00
amount_per_cycle - 20.00
profile_status - Active
charset - windows-1252
notify_version - 3.4
amount - 20.00
outstanding_balance - 0.00
---------->recurring_payment_id - I-6EFKVB5FXRGH
product_name - Ultimate Account
ipn_track_id - ...
显然，ProfileID 和 recurring_payment_id 是相等的。在此之后，收到有关付款的确认：
mc_gross - 20.00
outstanding_balance - 0.00
period_type - Regular
next_payment_date - 03:00:00 Oct 07, 2011 PDT
protection_eligibility - Ineligible
payment_cycle - Daily
tax - 0.00
payer_id - WR942TMLKNKZE
payment_date - 04:38:37 Oct 06, 2011 PDT
payment_status - Completed
product_name - Ultimate Account
charset - windows-1252
---------->recurring_payment_id - I-5S42CVRD6HPC
first_name - Test
mc_fee - 0.88
notify_version - 3.4
amount_per_cycle - 20.00
payer_status - verified
currency_code - USD
business - ...
verify_sign - ...
payer_email - ...
initial_payment_amount - 0.00
profile_status - Active
amount - 20.00
txn_id - 2XB154738E303273C
payment_type - instant
last_name - User
receiver_email - ...
payment_fee - 0.88
receiver_id - ...
txn_type - recurring_payment
mc_currency - USD
residence_country - US
test_ipn - 1
transaction_subject -
payment_gross - 20.00
shipping - 0.00
product_type - 1
time_created - 03:32:45 Sep 29, 2011 PDT
ipn_track_id - ...
这 3 个值： ProfileID 返回 CreateRecurringPaymentsProfile()；recurring_payment_profile_created 中的 recurring_payment_id；recurring_payment 中的 recurring_payment_id - 应该相同。（因为似乎没有其他方法可以正确识别此特定订阅的付款）此外，Paypal 多次发送 recurring_payment（在 IPN 上）并且每次 recurring_payment_id 都不同。
我应该使用 recurring_payment_id 来识别特定订阅的付款还是有另一种正确的方法来识别它？