uncloud/uncloud_pay/stripe.py

import stripe
import stripe.error
import logging
import datetime

from django.core.exceptions import ObjectDoesNotExist, ValidationError
from django.conf import settings
from django.contrib.auth import get_user_model

from .models import StripeCustomer, StripeCreditCard

CURRENCY = 'chf'

stripe.api_key = settings.STRIPE_KEY

def handle_stripe_error(f):
    def handle_problems(*args, **kwargs):
        response = {
            'paid': False,
            'response_object': None,
            'error': None
        }

        common_message = "Currently it is not possible to make payments. Please try agin later."
        try:
            response_object = f(*args, **kwargs)
            return response_object
        except stripe.error.CardError as e:
            # Since it's a decline, stripe.error.CardError will be caught
            body = e.json_body
            logging.error(str(e))

            raise e # For error handling.
        except stripe.error.RateLimitError:
            logging.error("Too many requests made to the API too quickly.")
            raise Exception(common_message)
        except stripe.error.InvalidRequestError as e:
            logging.error(str(e))
            raise Exception('Invalid parameters.')
        except stripe.error.AuthenticationError as e:
            # Authentication with Stripe's API failed
            # (maybe you changed API keys recently)
            logging.error(str(e))
            raise Exception(common_message)
        except stripe.error.APIConnectionError as e:
            logging.error(str(e))
            raise Exception(common_message)
        except stripe.error.StripeError as e:
            # XXX: maybe send email
            logging.error(str(e))
            raise Exception(common_message)

    return handle_problems

def public_api_key():
    return settings.STRIPE_PUBLIC_KEY

def get_customer_id_for(user):
    try:
        # .get() raise if there is no matching entry.
        return StripeCustomer.objects.get(owner=user).stripe_id
    except ObjectDoesNotExist:
        # No entry yet - making a new one.
        try:
            customer = create_customer(user.username, user.email)
            uncloud_stripe_mapping = StripeCustomer.objects.create(
                    owner=user, stripe_id=customer.id)
            return uncloud_stripe_mapping.stripe_id
        except Exception as e:
            return None

@handle_stripe_error
def create_setup_intent(customer_id):
    return stripe.SetupIntent.create(customer=customer_id)

@handle_stripe_error
def get_setup_intent(setup_intent_id):
    return stripe.SetupIntent.retrieve(setup_intent_id)

def get_payment_method(payment_method_id):
    return stripe.PaymentMethod.retrieve(payment_method_id)

@handle_stripe_error
def create_customer(name, email):
    return stripe.Customer.create(name=name, email=email)

@handle_stripe_error
def get_customer(customer_id):
    return stripe.Customer.retrieve(customer_id)

@handle_stripe_error
def get_customer_cards(customer_id):
    print(f"getting cards for: {customer_id}")

    cards = []
    stripe_cards = stripe.PaymentMethod.list(
        customer=customer_id,
        type="card",
    )

    for stripe_card in stripe_cards["data"]:
        card = {}
        card['brand'] = stripe_card["card"]["brand"]
        card['last4'] = stripe_card["card"]["last4"]
        card['month'] = stripe_card["card"]["exp_month"]
        card['year']  = stripe_card["card"]["exp_year"]
        card['id']    = stripe_card["id"]

        cards.append(card)

    return cards

def sync_cards_for_user(user):
    customer_id = get_customer_id_for(user)
    cards = get_customer_cards(customer_id)

    active_cards = StripeCreditCard.objects.filter(owner=user,
                                                   active=True)

    if len(active_cards) > 0:
        has_active_card = True
    else:
        has_active_card = False

    for card in cards:
        active = False

        if not has_active_card:
            active = True
            has_active_card = True

        StripeCreditCard.objects.get_or_create(card_id=card['id'],
                                               owner = user,
                                               defaults = {
                                                   'last4': card['last4'],
                                                   'brand': card['brand'],
                                                   'expiry_date': datetime.date(card['year'],
                                                                                card['month'],
                                                                                1),
                                                   'active': active
                                                   }
                                               )

@handle_stripe_error
def charge_customer(user, amount, currency='CHF'):
    # Amount is in CHF but stripes requires smallest possible unit.
    # https://stripe.com/docs/api/payment_intents/create#create_payment_intent-amount
    # FIXME: might need to be adjusted for other currencies

    if currency == 'CHF':
        adjusted_amount = int(amount * 100)
    else:
        return Exception("Programming error: unsupported currency")

    try:
        card = StripeCreditCard.objects.get(owner=user,
                                     active=True)

    except StripeCreditCard.DoesNotExist:
        raise ValidationError("No active credit card - cannot create payment")

    customer_id = get_customer_id_for(user)

    return stripe.PaymentIntent.create(
        amount=adjusted_amount,
        currency=currency,
        customer=customer_id,
        payment_method=card.card_id,
        off_session=True,
        confirm=True,
    )