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https://github.com/bigchaindb/bigchaindb.git
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Pulled validate_transaction and validate_block out into a base ConsensusRules plugin class
This commit is contained in:
Matt Smith
parent
8a9030e5c0
commit
ee4720d1a5
107
bigchaindb/consensus/base.py
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107
bigchaindb/consensus/base.py
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@ -0,0 +1,107 @@
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import bigchaindb.exceptions as exceptions
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from bigchaindb.crypto import hash_data
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class ConsensusRules(object):
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"""Base consensus rules for Bigchain.
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This class can be copied to write your own consensus rules!
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Note: Consensus plugins will be executed in the order that they're listed in
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the bigchain config file.
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"""
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@classmethod
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def validate_transaction(cls, bigchain, transaction):
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"""Validate a transaction.
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Args:
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bigchain (Bigchain): an instantiated bigchaindb.Bigchain object.
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transaction (dict): transaction to validate.
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Returns:
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The transaction if the transaction is valid else it raises an
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exception describing the reason why the transaction is invalid.
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Raises:
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OperationError: if the transaction operation is not supported
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TransactionDoesNotExist: if the input of the transaction is not found
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TransactionOwnerError: if the new transaction is using an input it doesn't own
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DoubleSpend: if the transaction is a double spend
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InvalidHash: if the hash of the transaction is wrong
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InvalidSignature: if the signature of the transaction is wrong
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"""
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# If the operation is CREATE the transaction should have no inputs and
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# should be signed by a federation node
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if transaction['transaction']['operation'] == 'CREATE':
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if transaction['transaction']['input']:
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raise ValueError('A CREATE operation has no inputs')
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if transaction['transaction']['current_owner'] not in (
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bigchain.federation_nodes + [bigchain.me]):
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raise exceptions.OperationError(
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'Only federation nodes can use the operation `CREATE`')
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else:
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# check if the input exists, is owned by the current_owner
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if not transaction['transaction']['input']:
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raise ValueError(
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'Only `CREATE` transactions can have null inputs')
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tx_input = bigchain.get_transaction(
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transaction['transaction']['input'])
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if not tx_input:
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raise exceptions.TransactionDoesNotExist(
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'input `{}` does not exist in the bigchain'.format(
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transaction['transaction']['input']))
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if (tx_input['transaction']['new_owner'] !=
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transaction['transaction']['current_owner']):
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raise exceptions.TransactionOwnerError(
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'current_owner `{}` does not own the input `{}`'.format(
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transaction['transaction']['current_owner'],
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transaction['transaction']['input']))
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# check if the input was already spent by a transaction other than
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# this one.
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spent = bigchain.get_spent(tx_input['id'])
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if spent and spent['id'] != transaction['id']:
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raise exceptions.DoubleSpend(
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'input `{}` was already spent'.format(
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transaction['transaction']['input']))
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# Check hash of the transaction
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calculated_hash = hash_data(bigchain.serialize(
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transaction['transaction']))
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if calculated_hash != transaction['id']:
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raise exceptions.InvalidHash()
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# Check signature
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if not bigchain.verify_signature(transaction):
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raise exceptions.InvalidSignature()
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return transaction
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# TODO: check that the votings structure is correctly constructed
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@classmethod
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def validate_block(cls, bigchain, block):
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"""Validate a block.
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Args:
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bigchain (Bigchain): an instantiated bigchaindb.Bigchain object.
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block (dict): block to validate.
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Returns:
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The block if the block is valid else it raises and exception
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describing the reason why the block is invalid.
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Raises:
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InvalidHash: if the hash of the block is wrong.
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"""
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# Check if current hash is correct
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calculated_hash = hash_data(bigchain.serialize(block['block']))
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if calculated_hash != block['id']:
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raise exceptions.InvalidHash()
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return block
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@ -327,57 +327,16 @@ class Bigchain(object):
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transaction (dict): transaction to validate.
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Returns:
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The transaction if the transaction is valid else it raises and exception
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describing the reason why the transaction is invalid.
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Raises:
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OperationError: if the transaction operation is not supported
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TransactionDoesNotExist: if the input of the transaction is not found
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TransactionOwnerError: if the new transaction is using an input it doesn't own
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DoubleSpend: if the transaction is a double spend
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InvalidHash: if the hash of the transaction is wrong
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InvalidSignature: if the signature of the transaction is wrong
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The transaction if the transaction is valid else it raises an
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exception describing the reason why the transaction is invalid.
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"""
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# If the operation is CREATE the transaction should have no inputs and should be signed by a
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# federation node
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if transaction['transaction']['operation'] == 'CREATE':
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if transaction['transaction']['input']:
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raise ValueError('A CREATE operation has no inputs')
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if transaction['transaction']['current_owner'] not in self.federation_nodes + [self.me]:
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raise exceptions.OperationError('Only federation nodes can use the operation `CREATE`')
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else:
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# check if the input exists, is owned by the current_owner
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if not transaction['transaction']['input']:
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raise ValueError('Only `CREATE` transactions can have null inputs')
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tx_input = self.get_transaction(transaction['transaction']['input'])
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if not tx_input:
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raise exceptions.TransactionDoesNotExist('input `{}` does not exist in the bigchain'.format(
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transaction['transaction']['input']))
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if tx_input['transaction']['new_owner'] != transaction['transaction']['current_owner']:
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raise exceptions.TransactionOwnerError('current_owner `{}` does not own the input `{}`'.format(
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transaction['transaction']['current_owner'], transaction['transaction']['input']))
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# check if the input was already spent by a transaction other then this one.
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spent = self.get_spent(tx_input['id'])
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if spent:
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if spent['id'] != transaction['id']:
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raise exceptions.DoubleSpend('input `{}` was already spent'.format(
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transaction['transaction']['input']))
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# Check hash of the transaction
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calculated_hash = hash_data(self.serialize(transaction['transaction']))
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if calculated_hash != transaction['id']:
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raise exceptions.InvalidHash()
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# Check signature
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if not self.verify_signature(transaction):
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raise exceptions.InvalidSignature()
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for plugin in self.consensus_plugins:
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transaction = plugin.validate_transaction(self, transaction)
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return transaction
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def is_valid_transaction(self, transaction):
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"""Check whether a transacion is valid or invalid.
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@ -447,12 +406,13 @@ class Bigchain(object):
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"""
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# 1. Check if current hash is correct
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calculated_hash = hash_data(self.serialize(block['block']))
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if calculated_hash != block['id']:
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raise exceptions.InvalidHash()
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# First run all of the plugin block validation logic
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for plugin in self.consensus_plugins:
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transaction = plugin.validate_block(self, block)
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# 2. Validate all transactions in the block
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# Finally: Tentative assumption that every blockchain will want to
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# validate all transactions in each block
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for transaction in block['block']['transactions']:
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if not self.is_valid_transaction(transaction):
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# this will raise the exception
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