stellar_sdk/operation/operation.py
from abc import ABCMeta, abstractmethod
from decimal import Decimal
from typing import Optional, Union
from .. import utils
from .. import xdr as stellar_xdr
from ..muxed_account import MuxedAccount
__all__ = ["Operation"]
class Operation(metaclass=ABCMeta):
"""The :class:`Operation` object, which represents an operation on
Stellar's network.
An operation is an individual command that mutates Stellar's ledger. It is
typically rolled up into a transaction (a transaction is a list of
operations with additional metadata).
Operations are executed on behalf of the source account specified in the
transaction, unless there is an override defined for the operation.
For more on operations, see `Stellar's documentation on operations
<https://developers.stellar.org/docs/glossary/operations/>`_ as
well as `Stellar's List of Operations
<https://developers.stellar.org/docs/start/list-of-operations/>`_,
which includes information such as the security necessary for a given
operation, as well as information about when validity checks occur on the
network.
The :class:`Operation` class is typically not used, but rather one of its
subclasses is typically included in transactions.
:param source: The source account for the operation. Defaults to the
transaction's source account.
"""
def __init__(self, source: Optional[Union[MuxedAccount, str]] = None) -> None:
if isinstance(source, str):
source = MuxedAccount.from_account(source)
self.source: Optional[MuxedAccount] = source
@property
@abstractmethod
def _XDR_OPERATION_TYPE(self) -> stellar_xdr.OperationType:
pass # pragma: no cover
@staticmethod
def to_xdr_amount(value: Union[str, Decimal]) -> int:
"""Converts an amount to the appropriate value to send over the network
as a part of an XDR object.
Each asset amount is encoded as a signed 64-bit integer in the XDR
structures. An asset amount unit (that which is seen by end users) is
scaled down by a factor of ten million (10,000,000) to arrive at the
native 64-bit integer representation. For example, the integer amount
value 25,123,456 equals 2.5123456 units of the asset. This scaling
allows for seven decimal places of precision in human-friendly amount
units.
This static method correctly multiplies the value by the scaling factor
in order to come to the integer value used in XDR structures.
See `Stellar's documentation on Asset Precision
<https://developers.stellar.org/docs/issuing-assets/anatomy-of-an-asset/#amount-precision>`_
for more information.
:param value: The amount to convert to an integer for XDR
serialization.
"""
return utils.to_xdr_amount(value)
@staticmethod
def from_xdr_amount(value: int) -> str:
"""Converts a str amount from an XDR amount object
:param value: The amount to convert to a string from an XDR int64
amount.
"""
return utils.from_xdr_amount(value)
@abstractmethod
def _to_operation_body(self) -> stellar_xdr.OperationBody:
pass # pragma: no cover
def to_xdr_object(self) -> stellar_xdr.Operation:
"""Creates an XDR Operation object that represents this
:class:`Operation`.
"""
source_account = None
if self.source:
source_account = self.source.to_xdr_object()
return stellar_xdr.Operation(source_account, self._to_operation_body())
@classmethod
def from_xdr_object(cls, xdr_object: stellar_xdr.Operation) -> "Operation":
"""Create the appropriate :class:`Operation` subclass from the XDR
object.
:param xdr_object: The XDR object to create an :class:`Operation` (or
subclass) instance from.
"""
for sub_cls in cls.__subclasses__():
if sub_cls._XDR_OPERATION_TYPE == xdr_object.body.type:
return sub_cls.from_xdr_object(xdr_object)
raise NotImplementedError(
f"Operation of type={xdr_object.body.type} is not implemented."
)
@staticmethod
def get_source_from_xdr_obj(
xdr_object: stellar_xdr.Operation,
) -> Optional[MuxedAccount]:
"""Get the source account from account the operation xdr object.
:param xdr_object: the operation xdr object.
:return: The source account from account the operation xdr object.
"""
if xdr_object.source_account:
return MuxedAccount.from_xdr_object(xdr_object.source_account)
return None
def __hash__(self):
return hash(self.to_xdr_object())
def __eq__(self, other: object) -> bool:
if not isinstance(other, self.__class__):
return NotImplemented
return self.to_xdr_object() == other.to_xdr_object()