def prepare_transfer(inputs, outputs, metadata=None):
"""Create an instance of a :class:`~.Output`.
Args:
inputs (list of
(dict):
{
'tx': <(bigchaindb.common.transactionTransaction):
input transaction, can differ but must have same asset id>,
'output': <(int): output index of tx>
}
)
outputs (list of
(dict):
{
'condition': <(cryptoconditions.Condition): output condition>,
'public_keys': <(optional list of base58): for indexing defaults to `None`>,
'amount': <(int): defaults to `1`>
}
)
metadata (dict)
Raises:
TypeError: if `public_keys` is not instance of `list`.
"""
from bigchaindb.common.transaction import (Input, Output, TransactionLink)
from bigchaindb.models import Transaction
from cryptoconditions import (Fulfillment, Condition)
asset = inputs[0]['tx']['asset']
asset = {'id': asset['id'] if 'id' in asset else inputs[0]['tx']['id']}
_inputs, _outputs = [], []
for _input in inputs:
_output = _input['tx']['outputs'][_input['output']]
_inputs.append(
Input(fulfillment=Condition.from_uri(_output['condition']['uri']),
owners_before=_output['public_keys'],
fulfills=TransactionLink(txid=_input['tx']['id'],
output=_input['output'])))
for output in outputs:
_outputs.append(
Output(fulfillment=output['condition'],
public_keys=output['public_keys']
if "public_keys" in output else [],
amount=output['amount'] if "amount" in output else 1))
return Transaction(
operation='TRANSFER',
asset=asset,
inputs=_inputs,
outputs=_outputs,
metadata=metadata,
)
