def __init__(self, fulfillment, public_keys=None, amount=1):
"""Create an instance of a :class:`~.Output`.
Args:
fulfillment (:class:`cryptoconditions.Fulfillment`): A
Fulfillment to extract a Condition from.
public_keys (:obj:`list` of :obj:`str`, optional): A list of
owners before a Transaction was confirmed.
amount (int): The amount of Assets to be locked with this
Output.
Raises:
TypeError: if `public_keys` is not instance of `list`.
"""
if not isinstance(public_keys, list) and public_keys is not None:
raise TypeError('`public_keys` must be a list instance or None')
if not isinstance(amount, int):
raise TypeError('`amount` must be an int')
if amount < 1:
raise AmountError('`amount` must be greater than 0')
if amount > self.MAX_AMOUNT:
raise AmountError('`amount` must be <= %s' % self.MAX_AMOUNT)
self.fulfillment = fulfillment
self.amount = amount
self.public_keys = public_keys
def validate_asset(self, amount=None):
"""Validates the asset"""
if self.data is not None and not isinstance(self.data, dict):
raise TypeError('`data` must be a dict instance or None')
if not isinstance(self.divisible, bool):
raise TypeError('`divisible` must be a boolean')
if not isinstance(self.refillable, bool):
raise TypeError('`refillable` must be a boolean')
if not isinstance(self.updatable, bool):
raise TypeError('`updatable` must be a boolean')
if self.refillable:
raise NotImplementedError('Refillable assets are not yet'
' implemented')
if self.updatable:
raise NotImplementedError('Updatable assets are not yet'
' implemented')
# If the amount is supplied we can perform extra validations to
# the asset
if amount is not None:
if not isinstance(amount, int):
raise TypeError('`amount` must be an int')
if self.divisible is False and amount != 1:
raise AmountError('non divisible assets always have'
' amount equal to one')
# Since refillable assets are not yet implemented this should
# raise and exception
if self.divisible is True and amount < 2:
raise AmountError('divisible assets must have an amount'
' greater than one')
def from_dict(cls, data):
"""Transforms a Python dictionary to an Output object.
Note:
To pass a serialization cycle multiple times, a
Cryptoconditions Fulfillment needs to be present in the
passed-in dictionary, as Condition URIs are not serializable
anymore.
Args:
data (dict): The dict to be transformed.
Returns:
:class:`~bigchaindb.common.transaction.Output`
"""
try:
fulfillment = _fulfillment_from_details(
data['condition']['details'])
except KeyError:
# NOTE: Hashlock condition case
fulfillment = data['condition']['uri']
try:
amount = int(data['amount'])
except ValueError:
raise AmountError('Invalid amount: %s' % data['amount'])
return cls(fulfillment, data['public_keys'], amount)
def validate_transfer_inputs(self, bigchain, current_transactions=[]):
# store the inputs so that we can check if the asset ids match
input_txs = []
input_conditions = []
for input_ in self.inputs:
input_txid = input_.fulfills.txid
input_tx = bigchain.get_transaction(input_txid)
if input_tx is None:
for ctxn in current_transactions:
if ctxn.id == input_txid:
input_tx = ctxn
if input_tx is None:
raise InputDoesNotExist(
"input `{}` doesn't exist".format(input_txid))
spent = bigchain.get_spent(input_txid, input_.fulfills.output,
current_transactions)
if spent:
raise DoubleSpend(
'input `{}` was already spent'.format(input_txid))
output = input_tx.outputs[input_.fulfills.output]
input_conditions.append(output)
input_txs.append(input_tx)
# Validate that all inputs are distinct
links = [i.fulfills.to_uri() for i in self.inputs]
if len(links) != len(set(links)):
raise DoubleSpend('tx "{}" spends inputs twice'.format(self.id))
# validate asset id
asset_id = self.get_asset_id(input_txs)
if asset_id != self.asset['id']:
raise AssetIdMismatch(('The asset id of the input does not'
' match the asset id of the'
' transaction'))
input_amount = sum(
[input_condition.amount for input_condition in input_conditions])
output_amount = sum(
[output_condition.amount for output_condition in self.outputs])
if output_amount != input_amount:
raise AmountError(
('The amount used in the inputs `{}`'
' needs to be same as the amount used'
' in the outputs `{}`').format(input_amount, output_amount))
if not self.inputs_valid(input_conditions):
raise InvalidSignature('Transaction signature is invalid.')
return True
def generate(cls, public_keys, amount):
"""Generates a Output from a specifically formed tuple or list.
Note:
If a ThresholdCondition has to be generated where the threshold
is always the number of subconditions it is split between, a
list of the following structure is sufficient:
[(address|condition)*, [(address|condition)*, ...], ...]
Args:
public_keys (:obj:`list` of :obj:`str`): The public key of
the users that should be able to fulfill the Condition
that is being created.
amount (:obj:`int`): The amount locked by the Output.
Returns:
An Output that can be used in a Transaction.
Raises:
TypeError: If `public_keys` is not an instance of `list`.
ValueError: If `public_keys` is an empty list.
"""
threshold = len(public_keys)
if not isinstance(amount, int):
raise TypeError('`amount` must be a int')
if amount < 1:
raise AmountError('`amount` needs to be greater than zero')
if not isinstance(public_keys, list):
raise TypeError('`public_keys` must be an instance of list')
if len(public_keys) == 0:
raise ValueError('`public_keys` needs to contain at least one'
'owner')
elif len(public_keys) == 1 and not isinstance(public_keys[0], list):
if isinstance(public_keys[0], Fulfillment):
ffill = public_keys[0]
else:
ffill = Ed25519Sha256(
public_key=base58.b58decode(public_keys[0]))
return cls(ffill, public_keys, amount=amount)
else:
initial_cond = ThresholdSha256(threshold=threshold)
threshold_cond = reduce(cls._gen_condition, public_keys,
initial_cond)
return cls(threshold_cond, public_keys, amount=amount)
def validate(self, bigchain):
"""Validate a transaction.
Args:
bigchain (Bigchain): an instantiated bigchaindb.Bigchain object.
Returns:
The transaction (Transaction) if the transaction is valid else it
raises an exception describing the reason why the transaction is
invalid.
Raises:
OperationError: if the transaction operation is not supported
TransactionDoesNotExist: if the input of the transaction is not
found
TransactionNotInValidBlock: if the input of the transaction is not
in a valid block
TransactionOwnerError: if the new transaction is using an input it
doesn't own
DoubleSpend: if the transaction is a double spend
InvalidHash: if the hash of the transaction is wrong
InvalidSignature: if the signature of the transaction is wrong
"""
if len(self.inputs) == 0:
raise ValueError('Transaction contains no inputs')
input_conditions = []
inputs_defined = all([input_.fulfills for input_ in self.inputs])
# validate amounts
if any(output.amount < 1 for output in self.outputs):
raise AmountError('`amount` needs to be greater than zero')
if self.operation in (Transaction.CREATE, Transaction.GENESIS):
# validate asset
if self.asset['data'] is not None and not isinstance(
self.asset['data'], dict):
raise TypeError(('`asset.data` must be a dict instance or '
'None for `CREATE` transactions'))
# validate inputs
if inputs_defined:
raise ValueError('A CREATE operation has no inputs')
elif self.operation == Transaction.TRANSFER:
# validate asset
if not isinstance(self.asset['id'], str):
raise ValueError(('`asset.id` must be a string for '
'`TRANSFER` transations'))
# check inputs
if not inputs_defined:
raise ValueError('Only `CREATE` transactions can have null '
'inputs')
# store the inputs so that we can check if the asset ids match
input_txs = []
for input_ in self.inputs:
input_txid = input_.fulfills.txid
input_tx, status = bigchain.\
get_transaction(input_txid, include_status=True)
if input_tx is None:
raise TransactionDoesNotExist(
"input `{}` doesn't exist".format(input_txid))
if status != bigchain.TX_VALID:
raise TransactionNotInValidBlock(
'input `{}` does not exist in a valid block'.format(
input_txid))
spent = bigchain.get_spent(input_txid, input_.fulfills.output)
if spent and spent.id != self.id:
raise DoubleSpend(
'input `{}` was already spent'.format(input_txid))
output = input_tx.outputs[input_.fulfills.output]
input_conditions.append(output)
input_txs.append(input_tx)
if output.amount < 1:
raise AmountError('`amount` needs to be greater than zero')
# Validate that all inputs are distinct
links = [i.fulfills.to_uri() for i in self.inputs]
if len(links) != len(set(links)):
raise DoubleSpend('tx "{}" spends inputs twice'.format(
self.id))
# validate asset id
asset_id = Transaction.get_asset_id(input_txs)
if asset_id != self.asset['id']:
raise AssetIdMismatch(('The asset id of the input does not'
' match the asset id of the'
' transaction'))
# validate the amounts
for output in self.outputs:
if output.amount < 1:
raise AmountError('`amount` needs to be greater than zero')
input_amount = sum([
input_condition.amount for input_condition in input_conditions
])
output_amount = sum(
[output_condition.amount for output_condition in self.outputs])
if output_amount != input_amount:
raise AmountError(
('The amount used in the inputs `{}`'
' needs to be same as the amount used'
' in the outputs `{}`').format(input_amount,
output_amount))
else:
allowed_operations = ', '.join(Transaction.ALLOWED_OPERATIONS)
raise TypeError('`operation`: `{}` must be either {}.'.format(
self.operation, allowed_operations))
if not self.inputs_valid(input_conditions):
raise InvalidSignature('Transaction signature is invalid.')
return self
def validate(self, bigchain):
"""Validate transaction spend
Args:
bigchain (Bigchain): an instantiated bigchaindb.Bigchain object.
Returns:
The transaction (Transaction) if the transaction is valid else it
raises an exception describing the reason why the transaction is
invalid.
Raises:
ValidationError: If the transaction is invalid
"""
input_conditions = []
if self.operation == Transaction.TRANSFER:
# store the inputs so that we can check if the asset ids match
input_txs = []
for input_ in self.inputs:
input_txid = input_.fulfills.txid
input_tx, status = bigchain.\
get_transaction(input_txid, include_status=True)
if input_tx is None:
raise InputDoesNotExist(
"input `{}` doesn't exist".format(input_txid))
if status != bigchain.TX_VALID:
raise TransactionNotInValidBlock(
'input `{}` does not exist in a valid block'.format(
input_txid))
spent = bigchain.get_spent(input_txid, input_.fulfills.output)
if spent and spent.id != self.id:
raise DoubleSpend(
'input `{}` was already spent'.format(input_txid))
output = input_tx.outputs[input_.fulfills.output]
input_conditions.append(output)
input_txs.append(input_tx)
# Validate that all inputs are distinct
links = [i.fulfills.to_uri() for i in self.inputs]
if len(links) != len(set(links)):
raise DoubleSpend('tx "{}" spends inputs twice'.format(
self.id))
# validate asset id
asset_id = Transaction.get_asset_id(input_txs)
if asset_id != self.asset['id']:
raise AssetIdMismatch(('The asset id of the input does not'
' match the asset id of the'
' transaction'))
input_amount = sum([
input_condition.amount for input_condition in input_conditions
])
output_amount = sum(
[output_condition.amount for output_condition in self.outputs])
if output_amount != input_amount:
raise AmountError(
('The amount used in the inputs `{}`'
' needs to be same as the amount used'
' in the outputs `{}`').format(input_amount,
output_amount))
if not self.inputs_valid(input_conditions):
raise InvalidSignature('Transaction signature is invalid.')
return self
def validate(self, bigchain):
"""Validate a transaction.
Args:
bigchain (Bigchain): an instantiated bigchaindb.Bigchain object.
Returns:
The transaction (Transaction) if the transaction is valid else it
raises an exception describing the reason why the transaction is
invalid.
Raises:
OperationError: if the transaction operation is not supported
TransactionDoesNotExist: if the input of the transaction is not
found
TransactionNotInValidBlock: if the input of the transaction is not
in a valid block
TransactionOwnerError: if the new transaction is using an input it
doesn't own
DoubleSpend: if the transaction is a double spend
InvalidHash: if the hash of the transaction is wrong
InvalidSignature: if the signature of the transaction is wrong
"""
if len(self.fulfillments) == 0:
raise ValueError('Transaction contains no fulfillments')
input_conditions = []
inputs_defined = all([ffill.tx_input for ffill in self.fulfillments])
if self.operation in (Transaction.CREATE, Transaction.GENESIS):
# validate inputs
if inputs_defined:
raise ValueError('A CREATE operation has no inputs')
# validate asset
amount = sum([condition.amount for condition in self.conditions])
self.asset.validate_asset(amount=amount)
elif self.operation == Transaction.TRANSFER:
if not inputs_defined:
raise ValueError('Only `CREATE` transactions can have null '
'inputs')
# check inputs
# store the inputs so that we can check if the asset ids match
input_txs = []
input_amount = 0
for ffill in self.fulfillments:
input_txid = ffill.tx_input.txid
input_cid = ffill.tx_input.cid
input_tx, status = bigchain.\
get_transaction(input_txid, include_status=True)
if input_tx is None:
raise TransactionDoesNotExist(
"input `{}` doesn't exist".format(input_txid))
if status != bigchain.TX_VALID:
raise TransactionNotInValidBlock(
'input `{}` does not exist in a valid block'.format(
input_txid))
spent = bigchain.get_spent(input_txid, ffill.tx_input.cid)
if spent and spent.id != self.id:
raise DoubleSpend(
'input `{}` was already spent'.format(input_txid))
input_conditions.append(input_tx.conditions[input_cid])
input_txs.append(input_tx)
if input_tx.conditions[input_cid].amount < 1:
raise AmountError('`amount` needs to be greater than zero')
input_amount += input_tx.conditions[input_cid].amount
# validate asset id
asset_id = Asset.get_asset_id(input_txs)
if asset_id != self.asset.data_id:
raise AssetIdMismatch(('The asset id of the input does not'
' match the asset id of the'
' transaction'))
# get the asset creation to see if its divisible or not
asset = bigchain.get_asset_by_id(asset_id)
# validate the asset
asset.validate_asset(amount=input_amount)
# validate the amounts
output_amount = 0
for condition in self.conditions:
if condition.amount < 1:
raise AmountError('`amount` needs to be greater than zero')
output_amount += condition.amount
if output_amount != input_amount:
raise AmountError(
('The amount used in the inputs `{}`'
' needs to be same as the amount used'
' in the outputs `{}`').format(input_amount,
output_amount))
else:
allowed_operations = ', '.join(Transaction.ALLOWED_OPERATIONS)
raise TypeError('`operation`: `{}` must be either {}.'.format(
self.operation, allowed_operations))
if not self.fulfillments_valid(input_conditions):
raise InvalidSignature()
else:
return self