141 lines
4.0 KiB
Python
141 lines
4.0 KiB
Python
import hashlib
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import hmac
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import uuid
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import requests
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import structlog
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from django.conf import settings
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from vbv_lernwelt.core.admin import User
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from vbv_lernwelt.shop.models import CheckoutState
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logger = structlog.get_logger(__name__)
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class InitTransactionException(Exception):
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pass
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def is_signature_valid(
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signature: str,
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payload: bytes,
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hmac_key: str = settings.DATATRANS_HMAC_KEY,
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):
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"""
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See the docs: https://docs.datatrans.ch/docs/additional-security
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"""
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try:
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timestamp = signature.split(",")[0].split("=")[1]
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s0_expected = signature.split(",")[1].split("=")[1]
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key_hex_bytes = bytes.fromhex(hmac_key)
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timestamp_bytes = bytes(timestamp, "utf-8")
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s0_actual = hmac.new(
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key_hex_bytes, timestamp_bytes + payload, hashlib.sha256
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).hexdigest()
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except (IndexError, ValueError):
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logger.warning(
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"Invalid signature format Expected format: t=TIMESTAMP,s0=XXXX",
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signature=signature,
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)
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return False
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return s0_actual == s0_expected
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def init_transaction(
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user: User,
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amount_chf_centimes: int,
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redirect_url_success: str,
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redirect_url_error: str,
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redirect_url_cancel: str,
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webhook_url: str,
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):
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if overwrite := settings.DATATRANS_DEBUG_WEBHOOK_OVERWRITE:
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logger.warning(
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"APPLYING DEBUG DATATRANS WEBHOOK OVERWRITE!",
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webhook_url=overwrite,
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)
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webhook_url = overwrite
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payload = {
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# We use autoSettle=True, so that we don't have to settle the transaction:
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# -> Be aware that autoSettle has implications of the possible transaction states
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"autoSettle": True,
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"amount": amount_chf_centimes,
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"currency": "CHF",
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"language": user.language,
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"refno": str(uuid.uuid4()),
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"webhook": {"url": webhook_url},
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"redirect": {
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"successUrl": redirect_url_success,
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"errorUrl": redirect_url_error,
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"cancelUrl": redirect_url_cancel,
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},
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}
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logger.info("Initiating transaction", payload=payload)
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response = requests.post(
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url=f"{settings.DATATRANS_API_ENDPOINT}/v1/transactions",
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json=payload,
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headers={
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"Authorization": f"Basic {settings.DATATRANS_BASIC_AUTH_KEY}",
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"Content-Type": "application/json",
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},
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)
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if response.status_code == 201:
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transaction_id = response.json()["transactionId"]
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logger.info("Transaction initiated", transaction_id=transaction_id)
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return transaction_id
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else:
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raise InitTransactionException(
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"Transaction initiation failed:",
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response.json().get("error"),
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)
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def get_transaction_state(
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transaction_id: str,
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) -> CheckoutState:
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response = requests.get(
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f"{settings.DATATRANS_API_ENDPOINT}/v1/transactions/{transaction_id}",
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headers={
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"Authorization": f"Basic {settings.DATATRANS_BASIC_AUTH_KEY}",
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"Content-Type": "application/json",
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},
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)
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transaction_state = response.json()["status"]
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logger.info(
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"Transaction status retrieved",
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status_code=response.status_code,
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response=transaction_state,
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)
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return datatrans_state_to_checkout_state(transaction_state)
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def get_payment_url(transaction_id: str):
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return f"{settings.DATATRANS_PAY_URL}/v1/start/{transaction_id}"
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def datatrans_state_to_checkout_state(datatrans_transaction_state) -> CheckoutState:
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"""
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https://api-reference.datatrans.ch/#tag/v1transactions/operation/status
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"""
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if datatrans_transaction_state in ["settled", "transmitted"]:
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return CheckoutState.PAID
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elif datatrans_transaction_state == "failed":
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return CheckoutState.FAILED
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elif datatrans_transaction_state == "canceled":
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return CheckoutState.CANCELED
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else:
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# An intermediate state such as "initialized", "challenge_ongoing", etc.
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# -> we don't care about those states, we only care about final states here.
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return CheckoutState.ONGOING
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