Payments decline. Each SDK signals it differently: the given StripeApi returns paid False for a non-positive amount, and PayPalApi returns success False. But your adapters already fold both of those into a single field. Ok, so the caller never has to learn each provider's failure dialect.
Lean on that uniformity to write a client helper that reacts to the result. process_payment charges through any processor and returns the string SUCCESS when ok is true and DECLINED otherwise. One decision branch now covers every gateway, present and future.
class StripeApi:
def create_charge(self, amount_cents):
if amount_cents <= 0:
return {"id": "ch_declined", "paid": False}
return {"id": "ch_" + str(amount_cents), "paid": True}
class PayPalApi:
def make_payment(self, dollars):
if dollars <= 0:
return {"success": False, "txn": "pp_declined"}
return {"success": True, "txn": "pp_" + str(dollars)}
class PaymentProcessor:
def charge(self, amount_dollars):
raise NotImplementedError
class StripeAdapter(PaymentProcessor):
def __init__(self, api):
self._api = api
def charge(self, amount_dollars):
cents = int(round(amount_dollars * 100))
resp = self._api.create_charge(cents)
return {"ok": resp["paid"], "id": resp["id"]}
class PayPalAdapter(PaymentProcessor):
def __init__(self, api):
self._api = api
def charge(self, amount_dollars):
resp = self._api.make_payment(amount_dollars)
return {"ok": resp["success"], "id": resp["txn"]}
def checkout(processor, amount):
return processor.charge(amount)
def process_payment(processor, amount):
"""Return "SUCCESS" or "DECLINED" based on the charge result."""
# TODO: charge the amount through whatever processor you were handed, then
# branch on the ok field the adapters already normalized for you: hand back
# the string SUCCESS when it is true and the string DECLINED when it is not.
# Return those strings themselves, never booleans.
pass
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Payments decline. Each SDK signals it differently: the given StripeApi returns paid False for a non-positive amount, and PayPalApi returns success False. But your adapters already fold both of those into a single field. Ok, so the caller never has to learn each provider's failure dialect.
Lean on that uniformity to write a client helper that reacts to the result. process_payment charges through any processor and returns the string SUCCESS when ok is true and DECLINED otherwise. One decision branch now covers every gateway, present and future.
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