def vote(self, block_id, previous_block_id, decision, invalid_reason=None):
"""Create a signed vote for a block given the
:attr:`previous_block_id` and the :attr:`decision` (valid/invalid).
Args:
block_id (str): The id of the block to vote on.
previous_block_id (str): The id of the previous block.
decision (bool): Whether the block is valid or invalid.
invalid_reason (Optional[str]): Reason the block is invalid
"""
if block_id == previous_block_id:
raise exceptions.CyclicBlockchainError()
vote = {
'voting_for_block': block_id,
'previous_block': previous_block_id,
'is_block_valid': decision,
'invalid_reason': invalid_reason,
'timestamp': gen_timestamp()
}
vote_data = serialize(vote)
signature = crypto.PrivateKey(self.me_private).sign(vote_data.encode())
vote_signed = {
'node_pubkey': self.me,
'signature': signature.decode(),
'vote': vote
}
return vote_signed
def fulfill_escrow_asset(bigchain,
source,
to,
asset_id,
sk,
execution_fulfillment=None):
asset = bigchain.get_transaction(asset_id['txid'])
asset_owners = asset['transaction']['conditions'][
asset_id['cid']]['new_owners']
other_owner = [owner for owner in asset_owners if not owner == source][0]
# Create a base template for fulfill transaction
asset_escrow_fulfill = bigchain.create_transaction(
asset_owners,
to,
asset_id,
'TRANSFER',
payload=asset['transaction']['data']['payload'])
# Parse the threshold cryptocondition
escrow_fulfillment = cc.Fulfillment.from_dict(
asset['transaction']['conditions'][0]['condition']['details'])
# Get the fulfillment message to sign
tx_escrow_execute_fulfillment_message = \
bigchaindb.util.get_fulfillment_message(asset_escrow_fulfill,
asset_escrow_fulfill['transaction']['fulfillments'][0],
serialized=True)
# get the indices path for the source that wants to fulfill
_, indices = get_subcondition_indices_from_vk(escrow_fulfillment, source)
subfulfillment_source = escrow_fulfillment
for index in indices:
subfulfillment_source = subfulfillment_source.subconditions[index][
'body']
# sign the fulfillment
subfulfillment_source.sign(tx_escrow_execute_fulfillment_message,
crypto.PrivateKey(sk))
# get the indices path for the other source that delivers the condition
_, indices = get_subcondition_indices_from_vk(escrow_fulfillment,
other_owner)
subfulfillment_other = escrow_fulfillment.subconditions[indices[0]]['body']
# update the condition
del escrow_fulfillment.subconditions[indices[0]]
escrow_fulfillment.add_subcondition(subfulfillment_other.condition)
if execution_fulfillment:
_, indices = get_subcondition_indices_from_type(
escrow_fulfillment, cc.PreimageSha256Fulfillment.TYPE_ID)
del escrow_fulfillment.subconditions[indices[0]]['body'].subconditions[
indices[1]]
escrow_fulfillment.subconditions[
indices[0]]['body'].add_subfulfillment_uri(execution_fulfillment)
asset_escrow_fulfill['transaction']['fulfillments'][0][
'fulfillment'] = escrow_fulfillment.serialize_uri()
bigchain.write_transaction(asset_escrow_fulfill)
return asset_escrow_fulfill
