def from_dict(cls, block_body):
block = block_body['block']
block_serialized = serialize(block)
block_id = hash_data(block_serialized)
verifying_key = VerifyingKey(block['node_pubkey'])
try:
signature = block_body['signature']
except KeyError:
signature = None
if block_id != block_body['id']:
raise InvalidHash()
if signature is not None:
# NOTE: CC throws a `ValueError` on some wrong signatures
# https://github.com/bigchaindb/cryptoconditions/issues/27
try:
signature_valid = verifying_key.verify(block_serialized,
signature)
except ValueError:
signature_valid = False
if signature_valid is False:
raise InvalidSignature('Invalid block signature')
transactions = [Transaction.from_dict(tx) for tx
in block['transactions']]
return cls(transactions, block['node_pubkey'],
block['timestamp'], block['voters'], signature)
def to_dict(self):
if len(self.transactions) == 0:
raise OperationError('Empty block creation is not allowed')
block = {
'timestamp': self.timestamp,
'transactions': [tx.to_dict() for tx in self.transactions],
'node_pubkey': self.node_pubkey,
'voters': self.voters,
}
block_serialized = serialize(block)
block_id = hash_data(block_serialized)
return {
'id': block_id,
'block': block,
'signature': self.signature,
}