Policies

components.payment_gateway.subcomponents.authorizations.business_logic.policies.authorization_request_processing

AuthorizationRequestProcessingPolicy

AuthorizationRequestProcessingPolicy(
    workspace_key,
    expense_category_resolver,
    line_of_credit_resolver,
)

This class is responsible for processing authorization request events.

It also manages the lifecycle of the authorization requests upon receiving subsequent payment events.

Note

This policy is currently only supported for Adyen.

Source code in components/payment_gateway/subcomponents/authorizations/business_logic/policies/authorization_request_processing.py

def __init__(
    self,
    workspace_key: str,
    expense_category_resolver: ExpenseCategoryResolver,
    line_of_credit_resolver: LineOfCreditResolver,
):
    raise_on_provider_not_supported(workspace_key, PaymentServiceProvider.adyen)
    self.workspace_key = workspace_key
    self.expense_category_resolver = expense_category_resolver
    self.line_of_credit_resolver = line_of_credit_resolver

authorize_pending_transaction

authorize_pending_transaction(session, pending_transaction)

Authorize a pending transaction.

This method implements the core logic of the Authorization Relay, approving or declining pending transactions based on the high level design described here:

https://www.notion.so/alaninsurance/Authorization-Relay-High-Level-Design-1b21426e8be780e8ba04ee8b2a57deea?pvs=4 ⧉

Source code in components/payment_gateway/subcomponents/authorizations/business_logic/policies/authorization_request_processing.py

@obs.api_call()
def authorize_pending_transaction(
    self,
    session: Session,
    pending_transaction: PendingTransaction,
) -> AuthorizationResult:
    """Authorize a pending transaction.

    This method implements the core logic of the Authorization Relay,
    approving or declining pending transactions based on the high level
    design described here:

    https://www.notion.so/alaninsurance/Authorization-Relay-High-Level-Design-1b21426e8be780e8ba04ee8b2a57deea?pvs=4
    """
    expense_category_codes = (
        self.expense_category_resolver.resolve_expense_categories(
            pending_transaction
        )
    )
    if expense_category_codes is None or len(expense_category_codes) == 0:
        # Decline transactions that don't match any expense category
        return self._decline_pending_transaction(
            session,
            pending_transaction,
            reason="no_expense_category_match",
        )

    expense_category_ids = {
        ExpenseCategoryId(expense_category_id)
        for expense_category_id in ExpenseCategoryModelBroker.list_expense_category_ids_by_codes(
            session,
            list(expense_category_codes),
        )
    }
    if len(expense_category_ids) != len(expense_category_codes):
        # At least one expense category could not be resolved
        return self._decline_pending_transaction(
            session,
            pending_transaction,
            reason="expense_category_resolution_failed",
        )

    line_of_credit_ids = self.line_of_credit_resolver.resolve_lines_of_credit(
        expense_category_ids,
        pending_transaction,
    )
    if not line_of_credit_ids or len(line_of_credit_ids) != len(
        expense_category_ids
    ):
        return self._decline_pending_transaction(
            session,
            pending_transaction,
            reason="line_of_credit_resolution_failed",
        )

    # This operation is atomic
    result = ExpenseTrackerModelBroker.check_and_update_expensed_credits(
        session,
        [line_of_credit_id for line_of_credit_id in line_of_credit_ids],
        pending_transaction.amount,
    )
    if not result:
        return self._decline_pending_transaction(
            session,
            pending_transaction,
            reason="insufficient_credit",
        )

    return self._approve_pending_transaction(
        session,
        pending_transaction,
        expense_category_ids,
        line_of_credit_ids,
    )

expense_category_resolver instance-attribute

expense_category_resolver = expense_category_resolver

line_of_credit_resolver instance-attribute

line_of_credit_resolver = line_of_credit_resolver

on_payment_event

on_payment_event(session, data)

Process an incoming Adyen payment event.

This method is called when a payment event is received from Adyen. It extracts any pending transaction identifier from the payload and releases it if it exists.

Source code in components/payment_gateway/subcomponents/authorizations/business_logic/policies/authorization_request_processing.py

@obs.event_subscriber()
def on_payment_event(
    self,
    session: Session,
    data: "TransferData",
) -> None:
    """Process an incoming Adyen payment event.

    This method is called when a payment event is received from Adyen. It
    extracts any pending transaction identifier from the payload and
    releases it if it exists.
    """
    from components.payment_gateway.subcomponents.authorizations.adapters.adyen.helpers import (
        authorization_request_external_id_from_transfer_data,
    )

    external_id = authorization_request_external_id_from_transfer_data(data)
    if external_id is not None:
        self.update_active_transaction(
            session,
            workspace_key=self.workspace_key,
            external_id=external_id,
        )

update_active_transaction

update_active_transaction(
    session, workspace_key, external_id
)

Update a previously authorized transaction.

This method manages the lifecycle of the authorization requests upon events received from the PSP.

Source code in components/payment_gateway/subcomponents/authorizations/business_logic/policies/authorization_request_processing.py

@obs.api_call()
def update_active_transaction(
    self,
    session: Session,
    workspace_key: str,
    external_id: str,
) -> None:
    """Update a previously authorized transaction.

    This method manages the lifecycle of the authorization requests upon
    events received from the PSP.
    """
    self._release_pending_transaction(
        session,
        workspace_key,
        external_id,
    )

workspace_key instance-attribute

workspace_key = workspace_key