def validate(self, bigchain, current_transactions=[]):
"""Validate transaction spend
Args:
bigchain (BigchainDB): an instantiated bigchaindb.BigchainDB 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.CREATE:
duplicates = any(txn for txn in current_transactions
if txn.id == self.id)
if bigchain.is_committed(self.id) or duplicates:
raise DuplicateTransaction(
'transaction `{}` already exists'.format(self.id))
if not self.inputs_valid(input_conditions):
raise InvalidSignature('Transaction signature is invalid.')
elif self.operation == Transaction.TRANSFER:
self.validate_transfer_inputs(bigchain, current_transactions)
return self
def validate(self, bigchain, current_transactions=[]):
"""Validate election transaction
For more details refer BEP-21: https://github.com/bigchaindb/BEPs/tree/master/21
NOTE:
* A valid election is initiated by an existing validator.
* A valid election is one where voters are validators and votes are
alloacted according to the voting power of each validator node.
Args:
bigchain (BigchainDB): an instantiated bigchaindb.lib.BigchainDB object.
Returns:
ValidatorElection object
Raises:
ValidationError: If the election is invalid
"""
input_conditions = []
duplicates = any(txn for txn in current_transactions
if txn.id == self.id)
if bigchain.get_transaction(self.id) or duplicates:
raise DuplicateTransaction(
'transaction `{}` already exists'.format(self.id))
if not self.inputs_valid(input_conditions):
raise InvalidSignature('Transaction signature is invalid.')
current_validators = self.get_validators(bigchain)
# NOTE: Proposer should be a single node
if len(self.inputs) != 1 or len(self.inputs[0].owners_before) != 1:
raise MultipleInputsError(
'`tx_signers` must be a list instance of length one')
# NOTE: change more than 1/3 of the current power is not allowed
if self.asset['data']['power'] >= (1 / 3) * sum(
current_validators.values()):
raise InvalidPowerChange(
'`power` change must be less than 1/3 of total power')
# NOTE: Check if the proposer is a validator.
[election_initiator_node_pub_key] = self.inputs[0].owners_before
if election_initiator_node_pub_key not in current_validators.keys():
raise InvalidProposer(
'Public key is not a part of the validator set')
# NOTE: Check if all validators have been assigned votes equal to their voting power
if not self.is_same_topology(current_validators, self.outputs):
raise UnequalValidatorSet(
'Validator set much be exactly same to the outputs of election'
)
return self
def validate(self, bigchain, current_transactions=[]):
"""Validate election transaction
NOTE:
* A valid election is initiated by an existing validator.
* A valid election is one where voters are validators and votes are
allocated according to the voting power of each validator node.
Args:
:param bigchain: (BigchainDB) an instantiated bigchaindb.lib.BigchainDB object.
:param current_transactions: (list) A list of transactions to be validated along with the election
Returns:
Election: a Election object or an object of the derived Election subclass.
Raises:
ValidationError: If the election is invalid
"""
input_conditions = []
duplicates = any(txn for txn in current_transactions
if txn.id == self.id)
if bigchain.is_committed(self.id) or duplicates:
raise DuplicateTransaction(
'transaction `{}` already exists'.format(self.id))
if not self.inputs_valid(input_conditions):
raise InvalidSignature('Transaction signature is invalid.')
current_validators = self.get_validators(bigchain)
# NOTE: Proposer should be a single node
if len(self.inputs) != 1 or len(self.inputs[0].owners_before) != 1:
raise MultipleInputsError(
'`tx_signers` must be a list instance of length one')
# NOTE: Check if the proposer is a validator.
[election_initiator_node_pub_key] = self.inputs[0].owners_before
if election_initiator_node_pub_key not in current_validators.keys():
raise InvalidProposer(
'Public key is not a part of the validator set')
# NOTE: Check if all validators have been assigned votes equal to their voting power
if not self.is_same_topology(current_validators, self.outputs):
raise UnequalValidatorSet(
'Validator set much be exactly same to the outputs of election'
)
return self
def _validate_block_transactions(self, bigchain):
"""Validate Block transactions.
Args:
bigchain (Bigchain): an instantiated bigchaindb.Bigchain object.
Raises:
ValidationError: If an invalid transaction is found
"""
txids = [tx.id for tx in self.transactions]
if len(txids) != len(set(txids)):
raise DuplicateTransaction('Block has duplicate transaction')
for tx in self.transactions:
# If a transaction is not valid, `validate_transactions` will
# throw an an exception and block validation will be canceled.
bigchain.validate_transaction(tx)
def _validate_block(self, bigchain):
"""Validate the Block without validating the transactions.
Args:
bigchain (:class:`~bigchaindb.Bigchain`): An instantiated Bigchain
object.
Raises:
ValidationError: If there is a problem with the block
"""
# Check that the signature is valid
if not self.is_signature_valid():
raise InvalidSignature('Invalid block signature')
# Check that the block contains no duplicated transactions
txids = [tx.id for tx in self.transactions]
if len(txids) != len(set(txids)):
raise DuplicateTransaction('Block has duplicate transaction')
def validate(self, bigchain, current_transactions=[]):
"""Validate transaction spend
Args:
bigchain (BigchainDB): an instantiated bigchaindb.tendermint.BigchainDB 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.CREATE:
duplicates = any(txn for txn in current_transactions
if txn.id == self.id)
if bigchain.get_transaction(self.to_dict()['id']) or duplicates:
raise DuplicateTransaction(
'transaction `{}` already exists'.format(self.id))
elif 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:
for ctxn in current_transactions:
# assume that the status as valid for previously validated
# transactions in current round
if ctxn.id == input_txid:
input_tx = ctxn
status = bigchain.TX_VALID
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,
current_transactions)
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
