Files
stacks-puppet-node/blockstack_client/operations/transfer.py
2017-02-20 21:05:12 -05:00

280 lines
9.2 KiB
Python

#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Blockstack-client
~~~~~
copyright: (c) 2014-2015 by Halfmoon Labs, Inc.
copyright: (c) 2016 by Blockstack.org
This file is part of Blockstack-client.
Blockstack-client is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Blockstack-client is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Blockstack-client. If not, see <http://www.gnu.org/licenses/>.
"""
import pybitcoin
from pybitcoin import embed_data_in_blockchain, serialize_transaction, \
serialize_sign_and_broadcast, make_op_return_script, \
make_pay_to_address_script
from pybitcoin.transactions.outputs import calculate_change_amount
from utilitybelt import is_hex
from binascii import hexlify, unhexlify
from ..b40 import b40_to_hex, bin_to_b40, is_b40
from ..config import *
from ..scripts import *
import virtualchain
log = virtualchain.get_logger("blockstack-client")
def transfer_sanity_check( name, consensus_hash ):
"""
Verify that data for a transfer is valid.
Return True on success
Raise Exception on error
"""
if name is not None and (not is_b40( name ) or "+" in name or name.count(".") > 1):
raise Exception("Name '%s' has non-base-38 characters" % name)
# without the scheme, name must be 37 bytes
if name is not None and len(name) > LENGTH_MAX_NAME:
raise Exception("Name '%s' is too long; expected %s bytes" % (name, LENGTH_MAX_NAME))
return True
def build(name, keepdata, consensus_hash):
"""
Takes in a name to transfer. Name must include the namespace ID, but not the scheme.
Record format:
0 2 3 4 20 36
|-----|--|----|-------------------|---------------|
magic op keep hash128(name.ns_id) consensus hash
data?
"""
rc = transfer_sanity_check( name, consensus_hash )
if not rc:
raise Exception("Invalid transfer data")
data_disposition = None
if keepdata:
data_disposition = TRANSFER_KEEP_DATA
else:
data_disposition = TRANSFER_REMOVE_DATA
name_hash = hash256_trunc128( name )
disposition_hex = hexlify(data_disposition)
readable_script = 'NAME_TRANSFER 0x%s 0x%s 0x%s' % (disposition_hex, name_hash, consensus_hash)
hex_script = blockstack_script_to_hex(readable_script)
packaged_script = add_magic_bytes(hex_script)
return packaged_script
def make_outputs( data, inputs, new_name_owner_address, change_address, tx_fee=0, pay_fee=True):
"""
Builds the outputs for a name transfer operation.
Raise ValueError if there are not enough inputs to make the transaction
"""
dust_fee = None
op_fee = None
dust_value = DEFAULT_DUST_FEE
if pay_fee:
dust_fee = (len(inputs) + 2) * DEFAULT_DUST_FEE + DEFAULT_OP_RETURN_FEE + tx_fee
op_fee = DEFAULT_DUST_FEE
else:
dust_fee = 0
op_fee = 0
return [
# main output
{"script_hex": make_op_return_script(str(data), format='hex'),
"value": 0},
# new name owner output
{"script_hex": virtualchain.make_payment_script(new_name_owner_address),
"value": dust_value},
# change output
{"script_hex": virtualchain.make_payment_script(change_address),
"value": calculate_change_amount(inputs, op_fee, dust_fee)}
]
def make_transaction(name, destination_address, keepdata, consensus_hash, old_owner_addr, blockchain_client, tx_fee=0, subsidize=False, safety=True):
name = str(name)
destination_address = str(destination_address)
consensus_hash = str(consensus_hash)
old_owner_addr = str(old_owner_addr)
tx_fee = int(tx_fee)
assert len(consensus_hash) == LENGTH_CONSENSUS_HASH * 2
assert is_name_valid(name)
# sanity check
pay_fee = True
if subsidize:
pay_fee = False
inputs = tx_get_unspents( old_owner_addr, blockchain_client )
if safety:
assert len(inputs) > 0, "No UTXOs for {}".format(old_owner_addr)
nulldata = build(name, keepdata, consensus_hash)
outputs = make_outputs(nulldata, inputs, destination_address, old_owner_addr, tx_fee, pay_fee=pay_fee)
return (inputs, outputs)
def get_fees( inputs, outputs ):
"""
Given a transaction's outputs, look up its fees:
* the first output should be an OP_RETURN with the transfer info
* the second output should be the new owner's address, with a DEFAULT_DUST_FEE
* the third output should be the change address
Return (dust fees, operation fees) on success
Return (None, None) on invalid output listing
"""
if len(outputs) != 3:
return (None, None)
# 0: op_return
if not tx_output_is_op_return( outputs[0] ):
return (None, None)
if outputs[0]["value"] != 0:
return (None, None)
# 1: transfer address
if virtualchain.script_hex_to_address( outputs[1]["script_hex"] ) is None:
return (None, None)
# 2: change address
if virtualchain.script_hex_to_address( outputs[2]["script_hex"] ) is None:
return (None, None)
dust_fee = (len(inputs) + 2) * DEFAULT_DUST_FEE + DEFAULT_OP_RETURN_FEE
op_fee = DEFAULT_DUST_FEE
return (dust_fee, op_fee)
def find_last_transfer_consensus_hash( name_rec, block_id, vtxindex ):
"""
Given a name record, find the last non-NAME_TRANSFER consensus hash.
Return None if not found.
"""
from ..proxy import nameop_restore_from_history
history_keys = name_rec['history'].keys()
history_keys.sort()
history_keys.reverse()
for hk in history_keys:
name_history = name_rec['history']
history_states = nameop_restore_from_history( name_rec, name_history, hk )
for history_state in reversed(history_states):
if history_state['block_number'] > block_id or (history_state['block_number'] == block_id and history_state['vtxindex'] > vtxindex):
# from the future
continue
if history_state['op'][0] == NAME_TRANSFER:
# skip NAME_TRANSFERS
continue
if history_state['op'][0] == NAME_PREORDER:
# out of history
return None
if name_rec['consensus_hash'] is not None:
return name_rec['consensus_hash']
return None
def snv_consensus_extras( name_rec, block_id, blockchain_name_data, transfer_send_block_id_consensus_hash=None ):
"""
Given a name record most recently affected by an instance of this operation,
find the dict of consensus-affecting fields from the operation that are not
already present in the name record.
Specific to NAME_TRANSFER:
The consensus hash is a field that we snapshot when we discover the transfer,
but it is not a field that we preserve. It will instead be present in the
snapshots database, indexed by the block number in `transfer_send_block_id`.
(This is an artifact of a design quirk of a previous version of the system).
"""
from ..proxy import get_consensus_at
ret_op = {}
# reconstruct the recipient information
ret_op['recipient'] = str(name_rec['sender'])
ret_op['recipient_address'] = str(name_rec['address'])
# reconstruct name_hash, consensus_hash, keep_data
keep_data = None
try:
assert len(name_rec['op']) == 2, "Invalid op sequence '%s'" % (name_rec['op'])
if name_rec['op'][-1] == TRANSFER_KEEP_DATA:
keep_data = True
elif name_rec['op'][-1] == TRANSFER_REMOVE_DATA:
keep_data = False
else:
raise Exception("Invalid op sequence '%s'" % (name_rec['op']))
except Exception, e:
log.exception(e)
log.error("FATAL: invalid transfer op sequence")
os.abort()
ret_op['keep_data'] = keep_data
ret_op['name_hash128'] = hash256_trunc128( str(name_rec['name']) )
ret_op['sender_pubkey'] = None
if blockchain_name_data is None:
consensus_hash = find_last_transfer_consensus_hash( name_rec, block_id, name_rec['vtxindex'] )
ret_op['consensus_hash'] = consensus_hash
else:
ret_op['consensus_hash'] = blockchain_name_data['consensus_hash']
if ret_op['consensus_hash'] is None:
# no prior consensus hash; must be the one in the name operation itself
if transfer_send_block_id_consensus_hash is None:
# go look it up
ret_op['consensus_hash'] = get_consensus_at( name_rec['transfer_send_block_id'] )
else:
# caller already knows it
log.debug("consensus hash for %s is caller-given: %s" % (name_rec['transfer_send_block_id'], transfer_send_block_id_consensus_hash))
ret_op['consensus_hash'] = transfer_send_block_id_consensus_hash
return ret_op