stellar_sdk/fee_bump_transaction_envelope.py
from typing import Sequence, Union
from xdrlib3 import Packer
from . import xdr as stellar_xdr
from .base_transaction_envelope import BaseTransactionEnvelope
from .decorated_signature import DecoratedSignature
from .fee_bump_transaction import FeeBumpTransaction
__all__ = ["FeeBumpTransactionEnvelope"]
class FeeBumpTransactionEnvelope(BaseTransactionEnvelope["FeeBumpTransactionEnvelope"]):
"""The :class:`FeeBumpTransactionEnvelope` object, which represents a fee bump transaction
envelope ready to sign and submit to send over the network.
When a fee bump transaction is ready to be prepared for sending over the network, it
must be put into a :class:`FeeBumpTransactionEnvelope`, which includes additional
metadata such as the signers for a given transaction. Ultimately, this
class handles signing and conversion to and from XDR for usage on Stellar's
network.
See `Fee-Bump Transactions <https://developers.stellar.org/docs/glossary/fee-bumps/>`__ for more information.
See `CAP-0015 <https://github.com/stellar/stellar-protocol/blob/master/core/cap-0015.md>`__ for more information.
:param transaction: The fee bump transaction that is encapsulated in this envelope.
:param signatures: which contains a list of signatures that have
already been created.
:param network_passphrase: The network to connect to for verifying and retrieving additional attributes from.
"""
def __init__(
self,
transaction: FeeBumpTransaction,
network_passphrase: str,
signatures: Sequence[DecoratedSignature] = None,
) -> None:
super().__init__(network_passphrase, signatures)
self.transaction: FeeBumpTransaction = transaction
def signature_base(self) -> bytes:
"""Get the signature base of this transaction envelope.
Return the "signature base" of this transaction, which is the value
that, when hashed, should be signed to create a signature that
validators on the Stellar Network will accept.
It is composed of a 4 prefix bytes followed by the xdr-encoded form of
this transaction.
:return: The signature base of this transaction envelope.
"""
network_id = self._network_id
packer = Packer()
stellar_xdr.EnvelopeType.ENVELOPE_TYPE_TX_FEE_BUMP.pack(packer)
self.transaction.to_xdr_object().pack(packer)
return network_id + packer.get_buffer()
@staticmethod
def is_fee_bump_transaction_envelope(xdr: Union[str, bytes]) -> bool:
if isinstance(xdr, str):
xdr_object = stellar_xdr.TransactionEnvelope.from_xdr(xdr)
else:
xdr_object = stellar_xdr.TransactionEnvelope.from_xdr_bytes(xdr)
te_type = xdr_object.type
if te_type == stellar_xdr.EnvelopeType.ENVELOPE_TYPE_TX_FEE_BUMP:
return True
elif (
te_type == stellar_xdr.EnvelopeType.ENVELOPE_TYPE_TX
or te_type == stellar_xdr.EnvelopeType.ENVELOPE_TYPE_TX_V0
):
return False
else:
raise ValueError(
f"This transaction envelope type is not supported, type = {te_type}."
)
def to_xdr_object(self) -> stellar_xdr.TransactionEnvelope:
"""Get an XDR object representation of this :class:`TransactionEnvelope`.
:return: XDR TransactionEnvelope object
"""
tx = self.transaction.to_xdr_object()
te_type = stellar_xdr.EnvelopeType.ENVELOPE_TYPE_TX_FEE_BUMP
signatures = [signature.to_xdr_object() for signature in self.signatures]
tx_envelope = stellar_xdr.FeeBumpTransactionEnvelope(tx, signatures)
return stellar_xdr.TransactionEnvelope(type=te_type, fee_bump=tx_envelope)
@classmethod
def from_xdr_object(
cls, xdr_object: stellar_xdr.TransactionEnvelope, network_passphrase: str
) -> "FeeBumpTransactionEnvelope":
"""Create a new :class:`FeeBumpTransactionEnvelope` from an XDR object.
:param xdr_object: The XDR object that represents a fee bump transaction envelope.
:param network_passphrase: The network to connect to for verifying and retrieving additional attributes from.
:return: A new :class:`FeeBumpTransactionEnvelope` object from the given XDR TransactionEnvelope object.
"""
te_type = xdr_object.type
if te_type == stellar_xdr.EnvelopeType.ENVELOPE_TYPE_TX_FEE_BUMP:
assert xdr_object.fee_bump is not None
tx = FeeBumpTransaction.from_xdr_object(
xdr_object.fee_bump.tx, network_passphrase
)
else:
raise ValueError("Invalid EnvelopeType: %d.", xdr_object.type)
assert xdr_object.fee_bump is not None
signatures = [
DecoratedSignature.from_xdr_object(s)
for s in xdr_object.fee_bump.signatures
]
te = cls(tx, network_passphrase=network_passphrase, signatures=signatures)
return te
def __hash__(self):
return hash((self.transaction, self.network_passphrase, self.signatures))
def __eq__(self, other: object) -> bool:
if not isinstance(other, self.__class__):
return NotImplemented
return (
self.transaction == other.transaction
and self.network_passphrase == other.network_passphrase
and self.signatures == other.signatures
)
def __repr__(self):
return (
f"<FeeBumpTransactionEnvelope [transaction={self.transaction}, "
f"network_passphrase={self.network_passphrase}, signatures={self.signatures}]>"
)