I solved the problem.
It's related to the atomic requests. I had "ATOMIC_REQUESTS": True in the
database settings and XPAY's service responded so fast while the first
atomic-request hadn't finished yet, so it prevented the other callback-url
from accessing the same instance.
Thank you very much for your time and effort
On Wednesday, August 21, 2019 at 4:32:03 PM UTC+2, mohammed habib wrote:
>
> What is the Transaction class which your model inherits from ? Is it just
> a base model ?
>
> Let’s do an experiment
>
> Print(“object created”) right after the create() method
>
> Print(“callback requested”) on top of your callback method
>
> Which one do you see first ?
>
> Sent from my iPhone
>
> On 21 Aug 2019, at 16:56, Ahmed Shahwan <a...@shahwan.me <javascript:>>
> wrote:
>
> That's the class, nothing different other than HTTP requests
>
> class CashPayment(BasePayment):
> """Cash Payment Wrapper Class"""
>
> integration_id = CASH_INTEGRATION_ID
>
> def __init__(self, amount_cents: int, billing_data: dict):
> super().__init__(amount_cents, billing_data)
>
> def pay_request(self):
> """Step 4. issue Pay request"""
> payload = {
> "source": {"identifier": "cash", "subtype": "CASH"},
> "payment_token": self.payment_key_res.get("token"),
> }
> self.pay_req_res = self.hit_accept(
> self._api_url + "acceptance/payments/pay", payload=payload
> )
>
>
> On Wednesday, August 21, 2019 at 3:39:13 PM UTC+2, mohamed habib wrote:
>>
>> if you are able to share more code from the `utils.CashPayment` call that
>> may help us
>>
>> On Wed, Aug 21, 2019 at 4:37 PM mohamed habib <moe....@gmail.com> wrote:
>>
>>> I highly doubt its related to ORM or postgres, the creation of the
>>> record is synchronous so you can be sure that the record exists after the
>>> create() call.
>>>
>>> Since you are sure that you are fetching the data properly we can rule
>>> out this possibility
>>>
>>> Its probably a race condition of the callback arriving too soon *before*
>>> you hit the create() call. So do you know at what point your payment
>>> gateway will make the callback request and what would trigger it? Make sure
>>> you are
>>>
>>> On Wed, Aug 21, 2019 at 4:19 PM Ahmed Shahwan <a...@shahwan.me> wrote:
>>>
>>>> I tried, same happened. it's related to how Postgres works internally
>>>> with the Django-ORM.
>>>>
>>>> On Wednesday, August 21, 2019 at 3:07:47 PM UTC+2, mohamed habib wrote:
>>>>>
>>>>> Wild guess in the dark here, as I am unfamiliar with this API. you are
>>>>> doing:
>>>>>
>>>>> `payment.pay_request()`
>>>>>
>>>>> before creating the WeacceptTransaction object.
>>>>>
>>>>> Maybe this line needs to move below:
>>>>> `models.WeAcceptTransaction.objects.create(...)` ?
>>>>>
>>>>> At what point is the callback request triggered ?
>>>>>
>>>>> On Wed, Aug 21, 2019 at 3:36 PM Ahmed Shahwan <a...@shahwan.me> wrote:
>>>>>
>>>>>> Transaction model:
>>>>>>
>>>>>>
>>>>>> class WeacceptTransaction(Transaction):
>>>>>> """Weaccept's Transaction model"""
>>>>>>
>>>>>> # before frontend interaction
>>>>>> auth_token = models.TextField() # got from step 1
>>>>>> order_id = models.IntegerField(verbose_name="Accept's Order ID") #
>>>>>> id from step 2
>>>>>> order_url = models.CharField(max_length=255, null=True) #
>>>>>> order_url from step 2
>>>>>> billing_data = JSONField() # provided in request for paymet key,
>>>>>> step 3
>>>>>> payment_key = models.TextField() # payment_token from step 3
>>>>>> hmac = models.TextField(null=True)
>>>>>> # after (from callback)
>>>>>> success_status = models.BooleanField(default=False)
>>>>>> is_refunded = models.BooleanField(default=False)
>>>>>> reference_number = models.IntegerField(null=True)
>>>>>> processed_clbk_json = JSONField(null=True)
>>>>>>
>>>>>>
>>>>>> The cash_payment View:
>>>>>>
>>>>>> class CashPayment(APIView):
>>>>>> """Cash Payment endpoint"""
>>>>>>
>>>>>> serializer_class = serializers.CardPaymentSerializer
>>>>>> required_fields = ["amount_cents", "billing_data"]
>>>>>>
>>>>>> def post(self, request):
>>>>>> # Validate required fields
>>>>>> utils.validate(self.required_fields, request)
>>>>>> payment = utils.CashPayment(**request.data)
>>>>>> payment.prepare()
>>>>>> payment.pay_request()
>>>>>> # create a new transaction
>>>>>> models.WeacceptTransaction.objects.create(
>>>>>> merchant_order_id=payment.merchant_order_id,
>>>>>> amount=payment.amount_cents,
>>>>>> auth_token=payment.auth_res.get("token"),
>>>>>> order_id=payment.order_reg_res.get("id"),
>>>>>> order_url=payment.order_reg_res.get("order_url"),
>>>>>> billing_data=payment.billing_data,
>>>>>> payment_key=payment.payment_key_res.get("token"),
>>>>>> hmac=payment.pay_req_res.get("hmac"),
>>>>>> )
>>>>>>
>>>>>> return Response(
>>>>>> {
>>>>>> "message": "Our representative will go to the address
>>>>>> you provided "
>>>>>> "to collect the cash from you",
>>>>>> **payment.pay_req_res,
>>>>>> }
>>>>>> )
>>>>>>
>>>>>>
>>>>>> Please note: the first 3 steps are wrapped into the method `prepare()`
>>>>>> the 4th step is `pay_request()`
>>>>>>
>>>>>>
>>>>>> the callback-url endpoint (where the 5th step happens)
>>>>>>
>>>>>> class TransactionProcessedCallback(APIView):
>>>>>> """Processed callback that will recieve "TRANSACTION", "TOKEN", "
>>>>>> ORDER",
>>>>>> "DELIVERY_STATUS" objects"""
>>>>>>
>>>>>> def post(self, request):
>>>>>> # XXX extend to handle TOKEN, DELIVERY_STATUS objects... later
>>>>>> t_obj = request.data.get("obj") # transaction object
>>>>>> incoming_hmac = request.query_params.get("hmac")
>>>>>> calculated_hmac = utils.calculate_hmac_transaction(t_obj)
>>>>>>
>>>>>> # if not equal hmac, not coming from Accept!
>>>>>> if incoming_hmac != calculated_hmac:
>>>>>> return Response(
>>>>>> {"message": "invalid data"}, status=status.
>>>>>> HTTP_400_BAD_REQUEST
>>>>>> )
>>>>>>
>>>>>> import ipdb
>>>>>>
>>>>>> ipdb.set_trace()
>>>>>> # XXX: The error happens here
>>>>>> transaction = models.WeacceptTransaction.objects.get(
>>>>>> merchant_order_id=t_obj.get("order").get(
>>>>>> "merchant_order_id")
>>>>>> )
>>>>>> transaction.success_status = bool(t_obj.get("success"))
>>>>>> transaction.is_refunded = bool(t_obj.get("is_refunded"))
>>>>>> transaction.reference_number = int(t_obj.get("data").get(
>>>>>> "transaction_no") or 1)
>>>>>> transaction.processed_clbk_json = t_obj
>>>>>> transaction.save(
>>>>>> update_fields=[
>>>>>> "success_status",
>>>>>> "is_refunded",
>>>>>> "reference_number",
>>>>>> "processed_clbk_json",
>>>>>> ]
>>>>>> )
>>>>>>
>>>>>> email = t_obj.get("order").get("shipping_data").get("email")
>>>>>> # TODO: send mail based upon success status
>>>>>> try:
>>>>>> send_mail(
>>>>>> "Transaction Processed",
>>>>>> "Your transaction is processed",
>>>>>> "SERNDER MAIL",
>>>>>> [email],
>>>>>> fail_silently=False,
>>>>>> )
>>>>>> except Exception as ex:
>>>>>> print(">>>>>>>>>>FAILED TO SEND MAIL")
>>>>>> print(ex)
>>>>>>
>>>>>> return Response({"message": "Transaction Updated!"}, status=
>>>>>> status.HTTP_200_OK)
>>>>>>
>>>>>>
>>>>>> The 6th step (redirect-url) is irrelevant here, and not included in
>>>>>> the XPAY's service for this payment option.
>>>>>>
>>>>>>
>>>>>> On Wednesday, August 21, 2019 at 2:03:20 PM UTC+2, mohammed habib
>>>>>> wrote:
>>>>>>>
>>>>>>> Are you sure the callback request passes the right parameters ?
>>>>>>>
>>>>>>> Could you share some of your views code from the 6 steps, and your
>>>>>>> Transaction model ?
>>>>>>>
>>>>>>> Sent from my iPhone
>>>>>>>
>>>>>>> On 21 Aug 2019, at 14:46, Ahmed Shahwan <a...@shahwan.me> wrote:
>>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> I have a very strange problem that I don't know why it happens.
>>>>>>> I'm creating a REST API service that wraps another REST API payment
>>>>>>> service, let's call the other services XPAY. It has various payment
>>>>>>> options
>>>>>>> (Card, eWallet, Kiosk, and Cash). The steps required to use the
>>>>>>> services
>>>>>>> (to make a transaction)
>>>>>>>
>>>>>>> 1. authentication 2. order registration 3. payment key 4. prepare
>>>>>>> frontend based on payment type 5. Callback URL 6. Redirect URL
>>>>>>>
>>>>>>> and each step depends on its predecessor. The first 4 steps are
>>>>>>> performed through HTTP Requests that I issue from my service. I store
>>>>>>> some
>>>>>>> of the information I receive in those steps in a Model called
>>>>>>> Transaction.
>>>>>>> 5th and 6th steps are Callback endpoints that I create to receive
>>>>>>> further
>>>>>>> information about the status of the transaction that I started in the
>>>>>>> first
>>>>>>> 4 steps.
>>>>>>>
>>>>>>> My endpoints design is:
>>>>>>>
>>>>>>> myservice/payment/card
>>>>>>> myservice/payment/wallet
>>>>>>> myservice/payment/kiosk
>>>>>>> myservice/payment/cash
>>>>>>>
>>>>>>> myservice/payment/callback-url
>>>>>>> myservice/payment/redirect-url
>>>>>>>
>>>>>>> These endpoints are wrappers for the payment methods available in
>>>>>>> XPAY's service that my frontend apps will use to provide those payment
>>>>>>> options for users.
>>>>>>>
>>>>>>> I implemented the first 3 endpoints with no problem. inside those
>>>>>>> endpoints, I create a transaction object with a unique id and then
>>>>>>> update
>>>>>>> it from inside the *callback-url endpoint* after I receive the
>>>>>>> information from XPAY's service. Note that it takes some time between
>>>>>>> creating the Transaction object and saving it into the database from
>>>>>>> inside
>>>>>>> my endpoint, and updating it from inside the callback url endpoint.
>>>>>>>
>>>>>>> The weird thing happens in the 4th endpoint `cash` endpoint. XPAY's
>>>>>>> service responds very quickly on my *callback-url endpoint* and
>>>>>>> when it gets to the updating step, I get *Transaction.DoesNotExist *
>>>>>>> Exception while getting the transaction object
>>>>>>> using Transaction.objects.get(id=id).
>>>>>>>
>>>>>>> After some debugging time using ipdb I found that the instance has
>>>>>>> already been saved to the database! and I can retrieve it with its id.
>>>>>>> but
>>>>>>> when I let it run ordinarily the saving operation doesn't finish until
>>>>>>> that
>>>>>>> time (I got to know that using some print() statements), which is very
>>>>>>> strange, it's impossible that my laptop is that slow!
>>>>>>>
>>>>>>> Solutions I tried:
>>>>>>> 1. atomic transaction
>>>>>>> 2. time.sleep some time after making the request and saving the
>>>>>>> transaction object to the db
>>>>>>> 3. time.sleep in the callback-url before getting the transaction
>>>>>>> from DB
>>>>>>>
>>>>>>> I checked any possible logic error related to it and there's nothing
>>>>>>> illogical.
>>>>>>>
>>>>>>> the issue is related to Postgres and how it operates, and also with
>>>>>>> Django's ORM. I don't know.
>>>>>>>
>>>>>>> Main technologies I use:
>>>>>>> Django 2.2
>>>>>>> Postgres Docker container
>>>>>>> DRF
>>>>>>>
>>>>>>> I hope someone gives me an insight into why this is happening and
>>>>>>> how to work around it.
>>>>>>>
>>>>>>> Thanks
>>>>>>>
>>>>>>> --
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>>>>>>> Groups "Django users" group.
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>>>>>>>
>>>>>>> <https://groups.google.com/d/msgid/django-users/e43be322-bab9-4162-9fbc-05c6c9b95c94%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>>>>> .
>>>>>>>
>>>>>>> --
>>>>>> You received this message because you are subscribed to the Google
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>>>>>> send an email to django...@googlegroups.com.
>>>>>> To view this discussion on the web visit
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>>>>>>
>>>>>> <https://groups.google.com/d/msgid/django-users/a379e013-a01c-4c58-bf2b-0b4cd01f0fae%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>>>> .
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Best regards,
>>>>> *Mohammed M. Habib, PhD*
>>>>>
>>>>> --
>>>> You received this message because you are subscribed to the Google
>>>> Groups "Django users" group.
>>>> To unsubscribe from this group and stop receiving emails from it, send
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>>>> To view this discussion on the web visit
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>>>>
>>>> <https://groups.google.com/d/msgid/django-users/987c6ce7-70b6-49a9-ab3e-506e369d060e%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>> .
>>>>
>>>
>>>
>>> --
>>> Best regards,
>>> *Mohammed M. Habib, PhD*
>>>
>>>
>>
>> --
>> Best regards,
>> *Mohammed M. Habib, PhD*
>>
>> --
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