1112 lines
43 KiB
Python
1112 lines
43 KiB
Python
"""Transaction related models to parse and construct transaction
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payloads.
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"""
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from copy import deepcopy
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from functools import reduce
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import base58
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from cryptoconditions import Fulfillment, ThresholdSha256, Ed25519Sha256
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from cryptoconditions.exceptions import (
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ParsingError, ASN1DecodeError, ASN1EncodeError, UnsupportedTypeError)
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from bigchaindb.common.crypto import PrivateKey, hash_data
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from bigchaindb.common.exceptions import (KeypairMismatchException,
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InvalidHash, InvalidSignature,
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AmountError, AssetIdMismatch,
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ThresholdTooDeep)
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from bigchaindb.common.utils import serialize
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class Input(object):
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"""A Input is used to spend assets locked by an Output.
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Wraps around a Crypto-condition Fulfillment.
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Attributes:
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fulfillment (:class:`cryptoconditions.Fulfillment`): A Fulfillment
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to be signed with a private key.
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owners_before (:obj:`list` of :obj:`str`): A list of owners after a
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Transaction was confirmed.
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fulfills (:class:`~bigchaindb.common.transaction. TransactionLink`,
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optional): A link representing the input of a `TRANSFER`
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Transaction.
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"""
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def __init__(self, fulfillment, owners_before, fulfills=None):
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"""Create an instance of an :class:`~.Input`.
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Args:
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fulfillment (:class:`cryptoconditions.Fulfillment`): A
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Fulfillment to be signed with a private key.
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owners_before (:obj:`list` of :obj:`str`): A list of owners
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after a Transaction was confirmed.
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fulfills (:class:`~bigchaindb.common.transaction.
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TransactionLink`, optional): A link representing the input
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of a `TRANSFER` Transaction.
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"""
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if fulfills is not None and not isinstance(fulfills, TransactionLink):
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raise TypeError('`fulfills` must be a TransactionLink instance')
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if not isinstance(owners_before, list):
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raise TypeError('`owners_after` must be a list instance')
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self.fulfillment = fulfillment
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self.fulfills = fulfills
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self.owners_before = owners_before
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def __eq__(self, other):
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# TODO: If `other !== Fulfillment` return `False`
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return self.to_dict() == other.to_dict()
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def to_dict(self):
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"""Transforms the object to a Python dictionary.
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Note:
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If an Input hasn't been signed yet, this method returns a
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dictionary representation.
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Returns:
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dict: The Input as an alternative serialization format.
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"""
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try:
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fulfillment = self.fulfillment.serialize_uri()
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except (TypeError, AttributeError, ASN1EncodeError):
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fulfillment = _fulfillment_to_details(self.fulfillment)
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try:
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# NOTE: `self.fulfills` can be `None` and that's fine
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fulfills = self.fulfills.to_dict()
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except AttributeError:
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fulfills = None
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input_ = {
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'owners_before': self.owners_before,
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'fulfills': fulfills,
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'fulfillment': fulfillment,
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}
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return input_
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@classmethod
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def generate(cls, public_keys):
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# TODO: write docstring
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# The amount here does not really matter. It is only use on the
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# output data model but here we only care about the fulfillment
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output = Output.generate(public_keys, 1)
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return cls(output.fulfillment, public_keys)
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@classmethod
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def from_dict(cls, data):
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"""Transforms a Python dictionary to an Input object.
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Note:
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Optionally, this method can also serialize a Cryptoconditions-
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Fulfillment that is not yet signed.
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Args:
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data (dict): The Input to be transformed.
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Returns:
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:class:`~bigchaindb.common.transaction.Input`
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Raises:
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InvalidSignature: If an Input's URI couldn't be parsed.
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"""
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fulfillment = data['fulfillment']
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if not isinstance(fulfillment, Fulfillment):
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try:
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fulfillment = Fulfillment.from_uri(data['fulfillment'])
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except ASN1DecodeError:
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# TODO Remove as it is legacy code, and simply fall back on
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# ASN1DecodeError
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raise InvalidSignature("Fulfillment URI couldn't been parsed")
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except TypeError:
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# NOTE: See comment about this special case in
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# `Input.to_dict`
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fulfillment = _fulfillment_from_details(data['fulfillment'])
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fulfills = TransactionLink.from_dict(data['fulfills'])
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return cls(fulfillment, data['owners_before'], fulfills)
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def _fulfillment_to_details(fulfillment):
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"""
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Encode a fulfillment as a details dictionary
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Args:
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fulfillment: Crypto-conditions Fulfillment object
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"""
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if fulfillment.type_name == 'ed25519-sha-256':
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return {
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'type': 'ed25519-sha-256',
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'public_key': base58.b58encode(fulfillment.public_key),
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}
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if fulfillment.type_name == 'threshold-sha-256':
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subconditions = [
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_fulfillment_to_details(cond['body'])
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for cond in fulfillment.subconditions
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]
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return {
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'type': 'threshold-sha-256',
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'threshold': fulfillment.threshold,
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'subconditions': subconditions,
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}
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raise UnsupportedTypeError(fulfillment.type_name)
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def _fulfillment_from_details(data, _depth=0):
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"""
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Load a fulfillment for a signing spec dictionary
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Args:
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data: tx.output[].condition.details dictionary
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"""
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if _depth == 100:
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raise ThresholdTooDeep()
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if data['type'] == 'ed25519-sha-256':
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public_key = base58.b58decode(data['public_key'])
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return Ed25519Sha256(public_key=public_key)
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if data['type'] == 'threshold-sha-256':
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threshold = ThresholdSha256(data['threshold'])
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for cond in data['subconditions']:
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cond = _fulfillment_from_details(cond, _depth+1)
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threshold.add_subfulfillment(cond)
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return threshold
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raise UnsupportedTypeError(data.get('type'))
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class TransactionLink(object):
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"""An object for unidirectional linking to a Transaction's Output.
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Attributes:
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txid (str, optional): A Transaction to link to.
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output (int, optional): An output's index in a Transaction with id
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`txid`.
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"""
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def __init__(self, txid=None, output=None):
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"""Create an instance of a :class:`~.TransactionLink`.
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Note:
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In an IPLD implementation, this class is not necessary anymore,
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as an IPLD link can simply point to an object, as well as an
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objects properties. So instead of having a (de)serializable
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class, we can have a simple IPLD link of the form:
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`/<tx_id>/transaction/outputs/<output>/`.
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Args:
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txid (str, optional): A Transaction to link to.
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output (int, optional): An Outputs's index in a Transaction with
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id `txid`.
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"""
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self.txid = txid
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self.output = output
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def __bool__(self):
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return self.txid is not None and self.output is not None
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def __eq__(self, other):
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# TODO: If `other !== TransactionLink` return `False`
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return self.to_dict() == other.to_dict()
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def __hash__(self):
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return hash((self.txid, self.output))
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@classmethod
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def from_dict(cls, link):
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"""Transforms a Python dictionary to a TransactionLink object.
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Args:
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link (dict): The link to be transformed.
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Returns:
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:class:`~bigchaindb.common.transaction.TransactionLink`
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"""
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try:
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return cls(link['transaction_id'], link['output_index'])
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except TypeError:
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return cls()
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def to_dict(self):
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"""Transforms the object to a Python dictionary.
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Returns:
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(dict|None): The link as an alternative serialization format.
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"""
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if self.txid is None and self.output is None:
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return None
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else:
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return {
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'transaction_id': self.txid,
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'output_index': self.output,
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}
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def to_uri(self, path=''):
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if self.txid is None and self.output is None:
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return None
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return '{}/transactions/{}/outputs/{}'.format(path, self.txid,
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self.output)
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class Output(object):
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"""An Output is used to lock an asset.
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Wraps around a Crypto-condition Condition.
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Attributes:
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fulfillment (:class:`cryptoconditions.Fulfillment`): A Fulfillment
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to extract a Condition from.
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public_keys (:obj:`list` of :obj:`str`, optional): A list of
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owners before a Transaction was confirmed.
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"""
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MAX_AMOUNT = 9 * 10 ** 18
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def __init__(self, fulfillment, public_keys=None, amount=1):
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"""Create an instance of a :class:`~.Output`.
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Args:
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fulfillment (:class:`cryptoconditions.Fulfillment`): A
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Fulfillment to extract a Condition from.
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public_keys (:obj:`list` of :obj:`str`, optional): A list of
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owners before a Transaction was confirmed.
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amount (int): The amount of Assets to be locked with this
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Output.
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Raises:
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TypeError: if `public_keys` is not instance of `list`.
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"""
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if not isinstance(public_keys, list) and public_keys is not None:
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raise TypeError('`public_keys` must be a list instance or None')
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if not isinstance(amount, int):
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raise TypeError('`amount` must be an int')
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if amount < 1:
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raise AmountError('`amount` must be greater than 0')
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if amount > self.MAX_AMOUNT:
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raise AmountError('`amount` must be <= %s' % self.MAX_AMOUNT)
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self.fulfillment = fulfillment
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self.amount = amount
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self.public_keys = public_keys
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def __eq__(self, other):
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# TODO: If `other !== Condition` return `False`
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return self.to_dict() == other.to_dict()
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def to_dict(self):
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"""Transforms the object to a Python dictionary.
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Note:
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A dictionary serialization of the Input the Output was
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derived from is always provided.
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Returns:
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dict: The Output as an alternative serialization format.
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"""
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# TODO FOR CC: It must be able to recognize a hashlock condition
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# and fulfillment!
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condition = {}
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try:
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condition['details'] = _fulfillment_to_details(self.fulfillment)
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except AttributeError:
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pass
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try:
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condition['uri'] = self.fulfillment.condition_uri
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except AttributeError:
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condition['uri'] = self.fulfillment
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output = {
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'public_keys': self.public_keys,
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'condition': condition,
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'amount': str(self.amount),
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}
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return output
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@classmethod
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def generate(cls, public_keys, amount):
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"""Generates a Output from a specifically formed tuple or list.
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Note:
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If a ThresholdCondition has to be generated where the threshold
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is always the number of subconditions it is split between, a
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list of the following structure is sufficient:
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[(address|condition)*, [(address|condition)*, ...], ...]
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Args:
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public_keys (:obj:`list` of :obj:`str`): The public key of
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the users that should be able to fulfill the Condition
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that is being created.
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amount (:obj:`int`): The amount locked by the Output.
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Returns:
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An Output that can be used in a Transaction.
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Raises:
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TypeError: If `public_keys` is not an instance of `list`.
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ValueError: If `public_keys` is an empty list.
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"""
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threshold = len(public_keys)
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if not isinstance(amount, int):
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raise TypeError('`amount` must be a int')
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if amount < 1:
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raise AmountError('`amount` needs to be greater than zero')
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if not isinstance(public_keys, list):
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raise TypeError('`public_keys` must be an instance of list')
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if len(public_keys) == 0:
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raise ValueError('`public_keys` needs to contain at least one'
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'owner')
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elif len(public_keys) == 1 and not isinstance(public_keys[0], list):
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if isinstance(public_keys[0], Fulfillment):
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ffill = public_keys[0]
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else:
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ffill = Ed25519Sha256(
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public_key=base58.b58decode(public_keys[0]))
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return cls(ffill, public_keys, amount=amount)
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else:
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initial_cond = ThresholdSha256(threshold=threshold)
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threshold_cond = reduce(cls._gen_condition, public_keys,
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initial_cond)
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return cls(threshold_cond, public_keys, amount=amount)
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@classmethod
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def _gen_condition(cls, initial, new_public_keys):
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"""Generates ThresholdSha256 conditions from a list of new owners.
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Note:
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This method is intended only to be used with a reduce function.
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For a description on how to use this method, see
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:meth:`~.Output.generate`.
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Args:
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initial (:class:`cryptoconditions.ThresholdSha256`):
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A Condition representing the overall root.
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new_public_keys (:obj:`list` of :obj:`str`|str): A list of new
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owners or a single new owner.
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Returns:
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:class:`cryptoconditions.ThresholdSha256`:
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"""
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try:
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threshold = len(new_public_keys)
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except TypeError:
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threshold = None
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if isinstance(new_public_keys, list) and len(new_public_keys) > 1:
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ffill = ThresholdSha256(threshold=threshold)
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reduce(cls._gen_condition, new_public_keys, ffill)
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elif isinstance(new_public_keys, list) and len(new_public_keys) <= 1:
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raise ValueError('Sublist cannot contain single owner')
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else:
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try:
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new_public_keys = new_public_keys.pop()
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except AttributeError:
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pass
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# NOTE: Instead of submitting base58 encoded addresses, a user
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# of this class can also submit fully instantiated
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# Cryptoconditions. In the case of casting
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# `new_public_keys` to a Ed25519Fulfillment with the
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# result of a `TypeError`, we're assuming that
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# `new_public_keys` is a Cryptocondition then.
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if isinstance(new_public_keys, Fulfillment):
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ffill = new_public_keys
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else:
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ffill = Ed25519Sha256(
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public_key=base58.b58decode(new_public_keys))
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initial.add_subfulfillment(ffill)
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return initial
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@classmethod
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def from_dict(cls, data):
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"""Transforms a Python dictionary to an Output object.
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Note:
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To pass a serialization cycle multiple times, a
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Cryptoconditions Fulfillment needs to be present in the
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passed-in dictionary, as Condition URIs are not serializable
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anymore.
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Args:
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data (dict): The dict to be transformed.
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Returns:
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:class:`~bigchaindb.common.transaction.Output`
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"""
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try:
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fulfillment = _fulfillment_from_details(data['condition']['details'])
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except KeyError:
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# NOTE: Hashlock condition case
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fulfillment = data['condition']['uri']
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try:
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amount = int(data['amount'])
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except ValueError:
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raise AmountError('Invalid amount: %s' % data['amount'])
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return cls(fulfillment, data['public_keys'], amount)
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|
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class Transaction(object):
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"""A Transaction is used to create and transfer assets.
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|
|
Note:
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For adding Inputs and Outputs, this class provides methods
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to do so.
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|
|
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Attributes:
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operation (str): Defines the operation of the Transaction.
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inputs (:obj:`list` of :class:`~bigchaindb.common.
|
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transaction.Input`, optional): Define the assets to
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spend.
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|
outputs (:obj:`list` of :class:`~bigchaindb.common.
|
|
transaction.Output`, optional): Define the assets to lock.
|
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asset (dict): Asset payload for this Transaction. ``CREATE`` and
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``GENESIS`` Transactions require a dict with a ``data``
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property while ``TRANSFER`` Transactions require a dict with a
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``id`` property.
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metadata (dict):
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Metadata to be stored along with the Transaction.
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version (string): Defines the version number of a Transaction.
|
|
"""
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CREATE = 'CREATE'
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TRANSFER = 'TRANSFER'
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GENESIS = 'GENESIS'
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ALLOWED_OPERATIONS = (CREATE, TRANSFER, GENESIS)
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VERSION = '1.0'
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|
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def __init__(self, operation, asset, inputs=None, outputs=None,
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metadata=None, version=None):
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"""The constructor allows to create a customizable Transaction.
|
|
|
|
Note:
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When no `version` is provided, one is being
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generated by this method.
|
|
|
|
Args:
|
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operation (str): Defines the operation of the Transaction.
|
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asset (dict): Asset payload for this Transaction.
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inputs (:obj:`list` of :class:`~bigchaindb.common.
|
|
transaction.Input`, optional): Define the assets to
|
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outputs (:obj:`list` of :class:`~bigchaindb.common.
|
|
transaction.Output`, optional): Define the assets to
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lock.
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metadata (dict): Metadata to be stored along with the
|
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Transaction.
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version (string): Defines the version number of a Transaction.
|
|
"""
|
|
if operation not in Transaction.ALLOWED_OPERATIONS:
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allowed_ops = ', '.join(self.__class__.ALLOWED_OPERATIONS)
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raise ValueError('`operation` must be one of {}'
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.format(allowed_ops))
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|
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# Asset payloads for 'CREATE' and 'GENESIS' operations must be None or
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# dicts holding a `data` property. Asset payloads for 'TRANSFER'
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# operations must be dicts holding an `id` property.
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|
if (operation in [Transaction.CREATE, Transaction.GENESIS] and
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asset is not None and not (isinstance(asset, dict) and 'data' in asset)):
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raise TypeError(('`asset` must be None or a dict holding a `data` '
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|
" property instance for '{}' Transactions".format(operation)))
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|
elif (operation == Transaction.TRANSFER and
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not (isinstance(asset, dict) and 'id' in asset)):
|
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raise TypeError(('`asset` must be a dict holding an `id` property '
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"for 'TRANSFER' Transactions".format(operation)))
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|
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if outputs and not isinstance(outputs, list):
|
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raise TypeError('`outputs` must be a list instance or None')
|
|
|
|
if inputs and not isinstance(inputs, list):
|
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raise TypeError('`inputs` must be a list instance or None')
|
|
|
|
if metadata is not None and not isinstance(metadata, dict):
|
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raise TypeError('`metadata` must be a dict or None')
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|
|
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self.version = version if version is not None else self.VERSION
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self.operation = operation
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self.asset = asset
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|
self.inputs = inputs or []
|
|
self.outputs = outputs or []
|
|
self.metadata = metadata
|
|
|
|
@classmethod
|
|
def create(cls, tx_signers, recipients, metadata=None, asset=None):
|
|
"""A simple way to generate a `CREATE` transaction.
|
|
|
|
Note:
|
|
This method currently supports the following Cryptoconditions
|
|
use cases:
|
|
- Ed25519
|
|
- ThresholdSha256
|
|
|
|
Additionally, it provides support for the following BigchainDB
|
|
use cases:
|
|
- Multiple inputs and outputs.
|
|
|
|
Args:
|
|
tx_signers (:obj:`list` of :obj:`str`): A list of keys that
|
|
represent the signers of the CREATE Transaction.
|
|
recipients (:obj:`list` of :obj:`tuple`): A list of
|
|
([keys],amount) that represent the recipients of this
|
|
Transaction.
|
|
metadata (dict): The metadata to be stored along with the
|
|
Transaction.
|
|
asset (dict): The metadata associated with the asset that will
|
|
be created in this Transaction.
|
|
|
|
Returns:
|
|
:class:`~bigchaindb.common.transaction.Transaction`
|
|
"""
|
|
if not isinstance(tx_signers, list):
|
|
raise TypeError('`tx_signers` must be a list instance')
|
|
if not isinstance(recipients, list):
|
|
raise TypeError('`recipients` must be a list instance')
|
|
if len(tx_signers) == 0:
|
|
raise ValueError('`tx_signers` list cannot be empty')
|
|
if len(recipients) == 0:
|
|
raise ValueError('`recipients` list cannot be empty')
|
|
if not (asset is None or isinstance(asset, dict)):
|
|
raise TypeError('`asset` must be a dict or None')
|
|
|
|
inputs = []
|
|
outputs = []
|
|
|
|
# generate_outputs
|
|
for recipient in recipients:
|
|
if not isinstance(recipient, tuple) or len(recipient) != 2:
|
|
raise ValueError(('Each `recipient` in the list must be a'
|
|
' tuple of `([<list of public keys>],'
|
|
' <amount>)`'))
|
|
pub_keys, amount = recipient
|
|
outputs.append(Output.generate(pub_keys, amount))
|
|
|
|
# generate inputs
|
|
inputs.append(Input.generate(tx_signers))
|
|
|
|
return cls(cls.CREATE, {'data': asset}, inputs, outputs, metadata)
|
|
|
|
@classmethod
|
|
def transfer(cls, inputs, recipients, asset_id, metadata=None):
|
|
"""A simple way to generate a `TRANSFER` transaction.
|
|
|
|
Note:
|
|
Different cases for threshold conditions:
|
|
|
|
Combining multiple `inputs` with an arbitrary number of
|
|
`recipients` can yield interesting cases for the creation of
|
|
threshold conditions we'd like to support. The following
|
|
notation is proposed:
|
|
|
|
1. The index of a `recipient` corresponds to the index of
|
|
an input:
|
|
e.g. `transfer([input1], [a])`, means `input1` would now be
|
|
owned by user `a`.
|
|
|
|
2. `recipients` can (almost) get arbitrary deeply nested,
|
|
creating various complex threshold conditions:
|
|
e.g. `transfer([inp1, inp2], [[a, [b, c]], d])`, means
|
|
`a`'s signature would have a 50% weight on `inp1`
|
|
compared to `b` and `c` that share 25% of the leftover
|
|
weight respectively. `inp2` is owned completely by `d`.
|
|
|
|
Args:
|
|
inputs (:obj:`list` of :class:`~bigchaindb.common.transaction.
|
|
Input`): Converted `Output`s, intended to
|
|
be used as inputs in the transfer to generate.
|
|
recipients (:obj:`list` of :obj:`tuple`): A list of
|
|
([keys],amount) that represent the recipients of this
|
|
Transaction.
|
|
asset_id (str): The asset ID of the asset to be transferred in
|
|
this Transaction.
|
|
metadata (dict): Python dictionary to be stored along with the
|
|
Transaction.
|
|
|
|
Returns:
|
|
:class:`~bigchaindb.common.transaction.Transaction`
|
|
"""
|
|
if not isinstance(inputs, list):
|
|
raise TypeError('`inputs` must be a list instance')
|
|
if len(inputs) == 0:
|
|
raise ValueError('`inputs` must contain at least one item')
|
|
if not isinstance(recipients, list):
|
|
raise TypeError('`recipients` must be a list instance')
|
|
if len(recipients) == 0:
|
|
raise ValueError('`recipients` list cannot be empty')
|
|
|
|
outputs = []
|
|
for recipient in recipients:
|
|
if not isinstance(recipient, tuple) or len(recipient) != 2:
|
|
raise ValueError(('Each `recipient` in the list must be a'
|
|
' tuple of `([<list of public keys>],'
|
|
' <amount>)`'))
|
|
pub_keys, amount = recipient
|
|
outputs.append(Output.generate(pub_keys, amount))
|
|
|
|
if not isinstance(asset_id, str):
|
|
raise TypeError('`asset_id` must be a string')
|
|
|
|
inputs = deepcopy(inputs)
|
|
return cls(cls.TRANSFER, {'id': asset_id}, inputs, outputs, metadata)
|
|
|
|
def __eq__(self, other):
|
|
try:
|
|
other = other.to_dict()
|
|
except AttributeError:
|
|
return False
|
|
return self.to_dict() == other
|
|
|
|
def to_inputs(self, indices=None):
|
|
"""Converts a Transaction's outputs to spendable inputs.
|
|
|
|
Note:
|
|
Takes the Transaction's outputs and derives inputs
|
|
from that can then be passed into `Transaction.transfer` as
|
|
`inputs`.
|
|
A list of integers can be passed to `indices` that
|
|
defines which outputs should be returned as inputs.
|
|
If no `indices` are passed (empty list or None) all
|
|
outputs of the Transaction are returned.
|
|
|
|
Args:
|
|
indices (:obj:`list` of int): Defines which
|
|
outputs should be returned as inputs.
|
|
|
|
Returns:
|
|
:obj:`list` of :class:`~bigchaindb.common.transaction.
|
|
Input`
|
|
"""
|
|
# NOTE: If no indices are passed, we just assume to take all outputs
|
|
# as inputs.
|
|
indices = indices or range(len(self.outputs))
|
|
return [
|
|
Input(self.outputs[idx].fulfillment,
|
|
self.outputs[idx].public_keys,
|
|
TransactionLink(self.id, idx))
|
|
for idx in indices
|
|
]
|
|
|
|
def add_input(self, input_):
|
|
"""Adds an input to a Transaction's list of inputs.
|
|
|
|
Args:
|
|
input_ (:class:`~bigchaindb.common.transaction.
|
|
Input`): An Input to be added to the Transaction.
|
|
"""
|
|
if not isinstance(input_, Input):
|
|
raise TypeError('`input_` must be a Input instance')
|
|
self.inputs.append(input_)
|
|
|
|
def add_output(self, output):
|
|
"""Adds an output to a Transaction's list of outputs.
|
|
|
|
Args:
|
|
output (:class:`~bigchaindb.common.transaction.
|
|
Output`): An Output to be added to the
|
|
Transaction.
|
|
"""
|
|
if not isinstance(output, Output):
|
|
raise TypeError('`output` must be an Output instance or None')
|
|
self.outputs.append(output)
|
|
|
|
def sign(self, private_keys):
|
|
"""Fulfills a previous Transaction's Output by signing Inputs.
|
|
|
|
Note:
|
|
This method works only for the following Cryptoconditions
|
|
currently:
|
|
- Ed25519Fulfillment
|
|
- ThresholdSha256
|
|
Furthermore, note that all keys required to fully sign the
|
|
Transaction have to be passed to this method. A subset of all
|
|
will cause this method to fail.
|
|
|
|
Args:
|
|
private_keys (:obj:`list` of :obj:`str`): A complete list of
|
|
all private keys needed to sign all Fulfillments of this
|
|
Transaction.
|
|
|
|
Returns:
|
|
:class:`~bigchaindb.common.transaction.Transaction`
|
|
"""
|
|
# TODO: Singing should be possible with at least one of all private
|
|
# keys supplied to this method.
|
|
if private_keys is None or not isinstance(private_keys, list):
|
|
raise TypeError('`private_keys` must be a list instance')
|
|
|
|
# NOTE: Generate public keys from private keys and match them in a
|
|
# dictionary:
|
|
# key: public_key
|
|
# value: private_key
|
|
def gen_public_key(private_key):
|
|
# TODO FOR CC: Adjust interface so that this function becomes
|
|
# unnecessary
|
|
|
|
# cc now provides a single method `encode` to return the key
|
|
# in several different encodings.
|
|
public_key = private_key.get_verifying_key().encode()
|
|
# Returned values from cc are always bytestrings so here we need
|
|
# to decode to convert the bytestring into a python str
|
|
return public_key.decode()
|
|
|
|
key_pairs = {gen_public_key(PrivateKey(private_key)):
|
|
PrivateKey(private_key) for private_key in private_keys}
|
|
|
|
tx_dict = self.to_dict()
|
|
tx_dict = Transaction._remove_signatures(tx_dict)
|
|
tx_serialized = Transaction._to_str(tx_dict)
|
|
for i, input_ in enumerate(self.inputs):
|
|
self.inputs[i] = self._sign_input(input_, tx_serialized, key_pairs)
|
|
return self
|
|
|
|
@classmethod
|
|
def _sign_input(cls, input_, message, key_pairs):
|
|
"""Signs a single Input.
|
|
|
|
Note:
|
|
This method works only for the following Cryptoconditions
|
|
currently:
|
|
- Ed25519Fulfillment
|
|
- ThresholdSha256.
|
|
|
|
Args:
|
|
input_ (:class:`~bigchaindb.common.transaction.
|
|
Input`) The Input to be signed.
|
|
message (str): The message to be signed
|
|
key_pairs (dict): The keys to sign the Transaction with.
|
|
"""
|
|
if isinstance(input_.fulfillment, Ed25519Sha256):
|
|
return cls._sign_simple_signature_fulfillment(input_, message,
|
|
key_pairs)
|
|
elif isinstance(input_.fulfillment, ThresholdSha256):
|
|
return cls._sign_threshold_signature_fulfillment(input_, message,
|
|
key_pairs)
|
|
else:
|
|
raise ValueError("Fulfillment couldn't be matched to "
|
|
'Cryptocondition fulfillment type.')
|
|
|
|
@classmethod
|
|
def _sign_simple_signature_fulfillment(cls, input_, message, key_pairs):
|
|
"""Signs a Ed25519Fulfillment.
|
|
|
|
Args:
|
|
input_ (:class:`~bigchaindb.common.transaction.
|
|
Input`) The input to be signed.
|
|
message (str): The message to be signed
|
|
key_pairs (dict): The keys to sign the Transaction with.
|
|
"""
|
|
# NOTE: To eliminate the dangers of accidentally signing a condition by
|
|
# reference, we remove the reference of input_ here
|
|
# intentionally. If the user of this class knows how to use it,
|
|
# this should never happen, but then again, never say never.
|
|
input_ = deepcopy(input_)
|
|
public_key = input_.owners_before[0]
|
|
try:
|
|
# cryptoconditions makes no assumptions of the encoding of the
|
|
# message to sign or verify. It only accepts bytestrings
|
|
input_.fulfillment.sign(
|
|
message.encode(),
|
|
base58.b58decode(key_pairs[public_key].encode()),
|
|
)
|
|
except KeyError:
|
|
raise KeypairMismatchException('Public key {} is not a pair to '
|
|
'any of the private keys'
|
|
.format(public_key))
|
|
return input_
|
|
|
|
@classmethod
|
|
def _sign_threshold_signature_fulfillment(cls, input_, message, key_pairs):
|
|
"""Signs a ThresholdSha256.
|
|
|
|
Args:
|
|
input_ (:class:`~bigchaindb.common.transaction.
|
|
Input`) The Input to be signed.
|
|
message (str): The message to be signed
|
|
key_pairs (dict): The keys to sign the Transaction with.
|
|
"""
|
|
input_ = deepcopy(input_)
|
|
for owner_before in set(input_.owners_before):
|
|
# TODO: CC should throw a KeypairMismatchException, instead of
|
|
# our manual mapping here
|
|
|
|
# TODO FOR CC: Naming wise this is not so smart,
|
|
# `get_subcondition` in fact doesn't return a
|
|
# condition but a fulfillment
|
|
|
|
# TODO FOR CC: `get_subcondition` is singular. One would not
|
|
# expect to get a list back.
|
|
ccffill = input_.fulfillment
|
|
subffills = ccffill.get_subcondition_from_vk(
|
|
base58.b58decode(owner_before))
|
|
if not subffills:
|
|
raise KeypairMismatchException('Public key {} cannot be found '
|
|
'in the fulfillment'
|
|
.format(owner_before))
|
|
try:
|
|
private_key = key_pairs[owner_before]
|
|
except KeyError:
|
|
raise KeypairMismatchException('Public key {} is not a pair '
|
|
'to any of the private keys'
|
|
.format(owner_before))
|
|
|
|
# cryptoconditions makes no assumptions of the encoding of the
|
|
# message to sign or verify. It only accepts bytestrings
|
|
for subffill in subffills:
|
|
subffill.sign(message.encode(), base58.b58decode(private_key.encode()))
|
|
return input_
|
|
|
|
def inputs_valid(self, outputs=None):
|
|
"""Validates the Inputs in the Transaction against given
|
|
Outputs.
|
|
|
|
Note:
|
|
Given a `CREATE` or `GENESIS` Transaction is passed,
|
|
dummy values for Outputs are submitted for validation that
|
|
evaluate parts of the validation-checks to `True`.
|
|
|
|
Args:
|
|
outputs (:obj:`list` of :class:`~bigchaindb.common.
|
|
transaction.Output`): A list of Outputs to check the
|
|
Inputs against.
|
|
|
|
Returns:
|
|
bool: If all Inputs are valid.
|
|
"""
|
|
if self.operation in (Transaction.CREATE, Transaction.GENESIS):
|
|
# NOTE: Since in the case of a `CREATE`-transaction we do not have
|
|
# to check for outputs, we're just submitting dummy
|
|
# values to the actual method. This simplifies it's logic
|
|
# greatly, as we do not have to check against `None` values.
|
|
return self._inputs_valid(['dummyvalue'
|
|
for _ in self.inputs])
|
|
elif self.operation == Transaction.TRANSFER:
|
|
return self._inputs_valid([output.fulfillment.condition_uri
|
|
for output in outputs])
|
|
else:
|
|
allowed_ops = ', '.join(self.__class__.ALLOWED_OPERATIONS)
|
|
raise TypeError('`operation` must be one of {}'
|
|
.format(allowed_ops))
|
|
|
|
def _inputs_valid(self, output_condition_uris):
|
|
"""Validates an Input against a given set of Outputs.
|
|
|
|
Note:
|
|
The number of `output_condition_uris` must be equal to the
|
|
number of Inputs a Transaction has.
|
|
|
|
Args:
|
|
output_condition_uris (:obj:`list` of :obj:`str`): A list of
|
|
Outputs to check the Inputs against.
|
|
|
|
Returns:
|
|
bool: If all Outputs are valid.
|
|
"""
|
|
|
|
if len(self.inputs) != len(output_condition_uris):
|
|
raise ValueError('Inputs and '
|
|
'output_condition_uris must have the same count')
|
|
|
|
tx_dict = self.to_dict()
|
|
tx_dict = Transaction._remove_signatures(tx_dict)
|
|
tx_serialized = Transaction._to_str(tx_dict)
|
|
|
|
def validate(i, output_condition_uri=None):
|
|
""" Validate input against output condition URI """
|
|
return self._input_valid(self.inputs[i], self.operation,
|
|
tx_serialized, output_condition_uri)
|
|
|
|
return all(validate(i, cond)
|
|
for i, cond in enumerate(output_condition_uris))
|
|
|
|
@staticmethod
|
|
def _input_valid(input_, operation, tx_serialized, output_condition_uri=None):
|
|
"""Validates a single Input against a single Output.
|
|
|
|
Note:
|
|
In case of a `CREATE` or `GENESIS` Transaction, this method
|
|
does not validate against `output_condition_uri`.
|
|
|
|
Args:
|
|
input_ (:class:`~bigchaindb.common.transaction.
|
|
Input`) The Input to be signed.
|
|
operation (str): The type of Transaction.
|
|
tx_serialized (str): The Transaction used as a message when
|
|
initially signing it.
|
|
output_condition_uri (str, optional): An Output to check the
|
|
Input against.
|
|
|
|
Returns:
|
|
bool: If the Input is valid.
|
|
"""
|
|
ccffill = input_.fulfillment
|
|
try:
|
|
parsed_ffill = Fulfillment.from_uri(ccffill.serialize_uri())
|
|
except (TypeError, ValueError,
|
|
ParsingError, ASN1DecodeError, ASN1EncodeError):
|
|
return False
|
|
|
|
if operation in (Transaction.CREATE, Transaction.GENESIS):
|
|
# NOTE: In the case of a `CREATE` or `GENESIS` transaction, the
|
|
# output is always valid.
|
|
output_valid = True
|
|
else:
|
|
output_valid = output_condition_uri == ccffill.condition_uri
|
|
|
|
# NOTE: We pass a timestamp to `.validate`, as in case of a timeout
|
|
# condition we'll have to validate against it
|
|
|
|
# cryptoconditions makes no assumptions of the encoding of the
|
|
# message to sign or verify. It only accepts bytestrings
|
|
ffill_valid = parsed_ffill.validate(message=tx_serialized.encode())
|
|
return output_valid and ffill_valid
|
|
|
|
def to_dict(self):
|
|
"""Transforms the object to a Python dictionary.
|
|
|
|
Returns:
|
|
dict: The Transaction as an alternative serialization format.
|
|
"""
|
|
tx = {
|
|
'inputs': [input_.to_dict() for input_ in self.inputs],
|
|
'outputs': [output.to_dict() for output in self.outputs],
|
|
'operation': str(self.operation),
|
|
'metadata': self.metadata,
|
|
'asset': self.asset,
|
|
'version': self.version,
|
|
}
|
|
|
|
tx_no_signatures = Transaction._remove_signatures(tx)
|
|
tx_serialized = Transaction._to_str(tx_no_signatures)
|
|
tx_id = Transaction._to_hash(tx_serialized)
|
|
|
|
tx['id'] = tx_id
|
|
return tx
|
|
|
|
@staticmethod
|
|
# TODO: Remove `_dict` prefix of variable.
|
|
def _remove_signatures(tx_dict):
|
|
"""Takes a Transaction dictionary and removes all signatures.
|
|
|
|
Args:
|
|
tx_dict (dict): The Transaction to remove all signatures from.
|
|
|
|
Returns:
|
|
dict
|
|
|
|
"""
|
|
# NOTE: We remove the reference since we need `tx_dict` only for the
|
|
# transaction's hash
|
|
tx_dict = deepcopy(tx_dict)
|
|
for input_ in tx_dict['inputs']:
|
|
# NOTE: Not all Cryptoconditions return a `signature` key (e.g.
|
|
# ThresholdSha256), so setting it to `None` in any
|
|
# case could yield incorrect signatures. This is why we only
|
|
# set it to `None` if it's set in the dict.
|
|
input_['fulfillment'] = None
|
|
return tx_dict
|
|
|
|
@staticmethod
|
|
def _to_hash(value):
|
|
return hash_data(value)
|
|
|
|
@property
|
|
def id(self):
|
|
return self.to_hash()
|
|
|
|
def to_hash(self):
|
|
return self.to_dict()['id']
|
|
|
|
@staticmethod
|
|
def _to_str(value):
|
|
return serialize(value)
|
|
|
|
# TODO: This method shouldn't call `_remove_signatures`
|
|
def __str__(self):
|
|
tx = Transaction._remove_signatures(self.to_dict())
|
|
return Transaction._to_str(tx)
|
|
|
|
@staticmethod
|
|
def get_asset_ids(transactions):
|
|
if not isinstance(transactions, list):
|
|
transactions = [transactions]
|
|
|
|
if not len(transactions):
|
|
return []
|
|
|
|
# create a set of the transactions' asset ids
|
|
asset_ids = {tx.id if tx.operation == Transaction.CREATE
|
|
else tx.asset['id']
|
|
for tx in transactions}
|
|
|
|
return asset_ids
|
|
|
|
@staticmethod
|
|
def get_asset_id(transactions):
|
|
"""Get the asset id from a list of :class:`~.Transactions`.
|
|
|
|
This is useful when we want to check if the multiple inputs of a
|
|
transaction are related to the same asset id.
|
|
|
|
Args:
|
|
transactions (:obj:`list` of :class:`~bigchaindb.common.
|
|
transaction.Transaction`): A list of Transactions.
|
|
Usually input Transactions that should have a matching
|
|
asset ID.
|
|
|
|
Returns:
|
|
str: ID of the asset.
|
|
|
|
Raises:
|
|
:exc:`AssetIdMismatch`: If the inputs are related to different
|
|
assets.
|
|
"""
|
|
asset_ids = Transaction.get_asset_ids(transactions)
|
|
if len(asset_ids) == 0:
|
|
return None
|
|
|
|
# check that all the transasctions have the same asset id
|
|
if len(asset_ids) > 1:
|
|
raise AssetIdMismatch(('All inputs of all transactions passed'
|
|
' need to have the same asset id'))
|
|
return asset_ids.pop()
|
|
|
|
@staticmethod
|
|
def validate_id(tx_body):
|
|
"""Validate the transaction ID of a transaction
|
|
|
|
Args:
|
|
tx_body (dict): The Transaction to be transformed.
|
|
"""
|
|
# NOTE: Remove reference to avoid side effects
|
|
tx_body = deepcopy(tx_body)
|
|
try:
|
|
proposed_tx_id = tx_body.pop('id')
|
|
except KeyError:
|
|
raise InvalidHash('No transaction id found!')
|
|
|
|
tx_body_no_signatures = Transaction._remove_signatures(tx_body)
|
|
tx_body_serialized = Transaction._to_str(tx_body_no_signatures)
|
|
valid_tx_id = Transaction._to_hash(tx_body_serialized)
|
|
|
|
if proposed_tx_id != valid_tx_id:
|
|
err_msg = ("The transaction's id '{}' isn't equal to "
|
|
"the hash of its body, i.e. it's not valid.")
|
|
raise InvalidHash(err_msg.format(proposed_tx_id))
|
|
|
|
@classmethod
|
|
def from_dict(cls, tx):
|
|
"""Transforms a Python dictionary to a Transaction object.
|
|
|
|
Args:
|
|
tx_body (dict): The Transaction to be transformed.
|
|
|
|
Returns:
|
|
:class:`~bigchaindb.common.transaction.Transaction`
|
|
"""
|
|
cls.validate_id(tx)
|
|
inputs = [Input.from_dict(input_) for input_ in tx['inputs']]
|
|
outputs = [Output.from_dict(output) for output in tx['outputs']]
|
|
return cls(tx['operation'], tx['asset'], inputs, outputs,
|
|
tx['metadata'], tx['version'])
|
|
|