mirror of
https://github.com/bigchaindb/bigchaindb.git
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126 lines
5.1 KiB
Python
126 lines
5.1 KiB
Python
from bigchaindb.common.exceptions import (InvalidSignature, DoubleSpend,
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InputDoesNotExist,
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TransactionNotInValidBlock,
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AssetIdMismatch, AmountError,
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DuplicateTransaction)
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from bigchaindb.common.transaction import Transaction
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from bigchaindb.common.utils import (validate_txn_obj, validate_key)
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from bigchaindb.common.schema import validate_transaction_schema
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from bigchaindb.backend.schema import validate_language_key
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class Transaction(Transaction):
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def validate(self, bigchain, current_transactions=[]):
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"""Validate transaction spend
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Args:
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bigchain (BigchainDB): an instantiated bigchaindb.BigchainDB object.
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Returns:
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The transaction (Transaction) if the transaction is valid else it
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raises an exception describing the reason why the transaction is
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invalid.
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Raises:
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ValidationError: If the transaction is invalid
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"""
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input_conditions = []
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if self.operation == Transaction.CREATE:
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duplicates = any(txn for txn in current_transactions if txn.id == self.id)
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if bigchain.get_transaction(self.to_dict()['id']) or duplicates:
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raise DuplicateTransaction('transaction `{}` already exists'
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.format(self.id))
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elif self.operation == Transaction.TRANSFER:
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# store the inputs so that we can check if the asset ids match
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input_txs = []
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for input_ in self.inputs:
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input_txid = input_.fulfills.txid
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input_tx, status = bigchain.\
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get_transaction(input_txid, include_status=True)
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if input_tx is None:
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for ctxn in current_transactions:
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# assume that the status as valid for previously validated
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# transactions in current round
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if ctxn.id == input_txid:
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input_tx = ctxn
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status = bigchain.TX_VALID
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if input_tx is None:
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raise InputDoesNotExist("input `{}` doesn't exist"
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.format(input_txid))
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if status != bigchain.TX_VALID:
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raise TransactionNotInValidBlock(
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'input `{}` does not exist in a valid block'.format(
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input_txid))
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spent = bigchain.get_spent(input_txid, input_.fulfills.output,
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current_transactions)
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if spent and spent.id != self.id:
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raise DoubleSpend('input `{}` was already spent'
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.format(input_txid))
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output = input_tx.outputs[input_.fulfills.output]
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input_conditions.append(output)
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input_txs.append(input_tx)
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# Validate that all inputs are distinct
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links = [i.fulfills.to_uri() for i in self.inputs]
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if len(links) != len(set(links)):
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raise DoubleSpend('tx "{}" spends inputs twice'.format(self.id))
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# validate asset id
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asset_id = Transaction.get_asset_id(input_txs)
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if asset_id != self.asset['id']:
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raise AssetIdMismatch(('The asset id of the input does not'
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' match the asset id of the'
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' transaction'))
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input_amount = sum([input_condition.amount for input_condition in input_conditions])
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output_amount = sum([output_condition.amount for output_condition in self.outputs])
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if output_amount != input_amount:
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raise AmountError(('The amount used in the inputs `{}`'
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' needs to be same as the amount used'
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' in the outputs `{}`')
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.format(input_amount, output_amount))
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if not self.inputs_valid(input_conditions):
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raise InvalidSignature('Transaction signature is invalid.')
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return self
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@classmethod
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def from_dict(cls, tx_body):
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return super().from_dict(tx_body, False)
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@classmethod
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def validate_schema(cls, tx_body):
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cls.validate_id(tx_body)
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validate_transaction_schema(tx_body)
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validate_txn_obj('asset', tx_body['asset'], 'data', validate_key)
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validate_txn_obj('metadata', tx_body, 'metadata', validate_key)
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validate_language_key(tx_body['asset'], 'data')
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class FastTransaction:
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"""A minimal wrapper around a transaction dictionary. This is useful for
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when validation is not required but a routine expects something that looks
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like a transaction, for example during block creation.
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Note: immutability could also be provided
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"""
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def __init__(self, tx_dict):
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self.data = tx_dict
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@property
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def id(self):
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return self.data['id']
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def to_dict(self):
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return self.data
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