def get_spent(self, txid, output, current_transactions=[]):
transactions = backend.query.get_spent(self.connection, txid, output)
transactions = list(transactions) if transactions else []
if len(transactions) > 1:
raise core_exceptions.CriticalDoubleSpend(
'`{}` was spent more than once. There is a problem'
' with the chain'.format(txid))
current_spent_transactions = []
for ctxn in current_transactions:
for ctxn_input in ctxn.inputs:
if ctxn_input.fulfills and\
ctxn_input.fulfills.txid == txid and\
ctxn_input.fulfills.output == output:
current_spent_transactions.append(ctxn)
transaction = None
if len(transactions) + len(current_spent_transactions) > 1:
raise DoubleSpend('tx "{}" spends inputs twice'.format(txid))
elif transactions:
transaction = Transaction.from_db(self, transactions[0])
elif current_spent_transactions:
transaction = current_spent_transactions[0]
return transaction
def get_spent(self, txid, output, current_transactions=[]):
transactions = backend.query.get_spent(self.connection, txid, output)
transactions = list(transactions) if transactions else []
for ctxn in current_transactions:
for ctxn_input in ctxn.inputs:
if ctxn_input.fulfills.txid == txid and\
ctxn_input.fulfills.output == output:
transactions.append(ctxn.to_dict())
transaction = None
if len(transactions) > 1:
raise core_exceptions.CriticalDoubleSpend(
'`{}` was spent more than once. There is a problem'
' with the chain'.format(txid))
elif transactions:
transaction = transactions[0]
if transaction and transaction['operation'] == 'CREATE':
asset = backend.query.get_asset(self.connection, transaction['id'])
if asset:
transaction['asset'] = asset
else:
transaction['asset'] = {'data': None}
return Transaction.from_dict(transaction)
elif transaction and transaction['operation'] == 'TRANSFER':
return Transaction.from_dict(transaction)
else:
return None
def get_spent(self, txid, output):
"""Check if a `txid` was already used as an input.
A transaction can be used as an input for another transaction. Bigchain
needs to make sure that a given `(txid, output)` is only used once.
This method will check if the `(txid, output)` has already been
spent in a transaction that is in either the `VALID`, `UNDECIDED` or
`BACKLOG` state.
Args:
txid (str): The id of the transaction
output (num): the index of the output in the respective transaction
Returns:
The transaction (Transaction) that used the `(txid, output)` as an
input else `None`
Raises:
CriticalDoubleSpend: If the given `(txid, output)` was spent in
more than one valid transaction.
"""
# checks if an input was already spent
# checks if the bigchain has any transaction with input {'txid': ...,
# 'output': ...}
transactions = list(
backend.query.get_spent(self.connection, txid, output))
# a transaction_id should have been spent at most one time
# determine if these valid transactions appear in more than one valid
# block
num_valid_transactions = 0
non_invalid_transactions = []
for transaction in transactions:
# ignore transactions in invalid blocks
# FIXME: Isn't there a faster solution than doing I/O again?
txn, status = self.get_transaction(transaction['id'],
include_status=True)
if status == self.TX_VALID:
num_valid_transactions += 1
# `txid` can only have been spent in at most on valid block.
if num_valid_transactions > 1:
raise core_exceptions.CriticalDoubleSpend(
'`{}` was spent more than once. There is a problem'
' with the chain'.format(txid))
# if its not and invalid transaction
if status is not None:
transaction.update({'metadata': txn.metadata})
non_invalid_transactions.append(transaction)
if non_invalid_transactions:
return Transaction.from_dict(non_invalid_transactions[0])
def get_spent(self, txid, output):
"""Check if a `txid` was already used as an input.
A transaction can be used as an input for another transaction. Bigchain needs to make sure that a
given `txid` is only used once.
Args:
txid (str): The id of the transaction
output (num): the index of the output in the respective transaction
Returns:
The transaction (Transaction) that used the `txid` as an input else
`None`
"""
# checks if an input was already spent
# checks if the bigchain has any transaction with input {'txid': ...,
# 'output': ...}
transactions = list(
backend.query.get_spent(self.connection, txid, output))
# a transaction_id should have been spent at most one time
if transactions:
# determine if these valid transactions appear in more than one valid block
num_valid_transactions = 0
for transaction in transactions:
# ignore invalid blocks
# FIXME: Isn't there a faster solution than doing I/O again?
if self.get_transaction(transaction['id']):
num_valid_transactions += 1
if num_valid_transactions > 1:
raise core_exceptions.CriticalDoubleSpend(
'`{}` was spent more than once. There is a problem'
' with the chain'.format(txid))
if num_valid_transactions:
return Transaction.from_dict(transactions[0])
else:
# all queried transactions were invalid
return None
else:
return None
