#!/usr/bin/env python # # Use the raw transactions API to spend bitcoins received on particular addresses, # and send any change back to that same address. # # Example usage: # spendfrom.py # Lists available funds # spendfrom.py --from=ADDRESS --to=ADDRESS --amount=11.00 # # Assumes it will talk to a bitcoind or Bitcoin-Qt running # on localhost. # # Depends on jsonrpc # from decimal import * import getpass import math import os import os.path import platform import sys import time from jsonrpc import ServiceProxy, json BASE_FEE=Decimal("0.001") def check_json_precision(): """Make sure json library being used does not lose precision converting BTC values""" n = Decimal("20000000.00000003") satoshis = int(json.loads(json.dumps(float(n)))*1.0e8) if satoshis != 2000000000000003: raise RuntimeError("JSON encode/decode loses precision") def determine_db_dir(): """Return the default location of the bitcoin data directory""" if platform.system() == "Darwin": return os.path.expanduser("~/Library/Application Support/Bitcoin/") elif platform.system() == "Windows": return os.path.join(os.environ['APPDATA'], "Bitcoin") return os.path.expanduser("~/.bitcoin") def read_bitcoin_config(dbdir): """Read the bitcoin.conf file from dbdir, returns dictionary of settings""" from ConfigParser import SafeConfigParser class FakeSecHead(object): def __init__(self, fp): self.fp = fp self.sechead = '[all]\n' def readline(self): if self.sechead: try: return self.sechead finally: self.sechead = None else: s = self.fp.readline() if s.find('#') != -1: s = s[0:s.find('#')].strip() +"\n" return s config_parser = SafeConfigParser() config_parser.readfp(FakeSecHead(open(os.path.join(dbdir, "bitcoin.conf")))) return dict(config_parser.items("all")) def connect_JSON(config): """Connect to a bitcoin JSON-RPC server""" testnet = config.get('testnet', '0') testnet = (int(testnet) > 0) # 0/1 in config file, convert to True/False if not 'rpcport' in config: config['rpcport'] = 19332 if testnet else 9332 connect = "http://%s:%s@127.0.0.1:%s"%(config['rpcuser'], config['rpcpassword'], config['rpcport']) try: result = ServiceProxy(connect) # ServiceProxy is lazy-connect, so send an RPC command mostly to catch connection errors, # but also make sure the bitcoind we're talking to is/isn't testnet: if result.getmininginfo()['testnet'] != testnet: sys.stderr.write("RPC server at "+connect+" testnet setting mismatch\n") sys.exit(1) return result except: sys.stderr.write("Error connecting to RPC server at "+connect+"\n") sys.exit(1) def unlock_wallet(bitcoind): info = bitcoind.getinfo() if 'unlocked_until' not in info: return True # wallet is not encrypted t = int(info['unlocked_until']) if t <= time.time(): try: passphrase = getpass.getpass("Wallet is locked; enter passphrase: ") bitcoind.walletpassphrase(passphrase, 5) except: sys.stderr.write("Wrong passphrase\n") info = bitcoind.getinfo() return int(info['unlocked_until']) > time.time() def list_available(bitcoind): address_summary = dict() address_to_account = dict() for info in bitcoind.listreceivedbyaddress(0): address_to_account[info["address"]] = info["account"] unspent = bitcoind.listunspent(0) for output in unspent: # listunspent doesn't give addresses, so: rawtx = bitcoind.getrawtransaction(output['txid'], 1) vout = rawtx["vout"][output['vout']] pk = vout["scriptPubKey"] # This code only deals with ordinary pay-to-bitcoin-address # or pay-to-script-hash outputs right now; anything exotic is ignored. if pk["type"] != "pubkeyhash" and pk["type"] != "scripthash": continue address = pk["addresses"][0] if address in address_summary: address_summary[address]["total"] += vout["value"] address_summary[address]["outputs"].append(output) else: address_summary[address] = { "total" : vout["value"], "outputs" : [output], "account" : address_to_account.get(address, "") } return address_summary def select_coins(needed, inputs): # Feel free to improve this, this is good enough for my simple needs: outputs = [] have = Decimal("0.0") n = 0 while have < needed and n < len(inputs): outputs.append({ "txid":inputs[n]["txid"], "vout":inputs[n]["vout"]}) have += inputs[n]["amount"] n += 1 return (outputs, have-needed) def create_tx(bitcoind, fromaddresses, toaddress, amount, fee): all_coins = list_available(bitcoind) total_available = Decimal("0.0") needed = amount+fee potential_inputs = [] for addr in fromaddresses: if addr not in all_coins: continue potential_inputs.extend(all_coins[addr]["outputs"]) total_available += all_coins[addr]["total"] if total_available < needed: sys.stderr.write("Error, only %f BTC available, need %f\n"%(total_available, needed)); sys.exit(1) # # Note: # Python's json/jsonrpc modules have inconsistent support for Decimal numbers. # Instead of wrestling with getting json.dumps() (used by jsonrpc) to encode # Decimals, I'm casting amounts to float before sending them to bitcoind. # outputs = { toaddress : float(amount) } (inputs, change_amount) = select_coins(needed, potential_inputs) if change_amount > BASE_FEE: # don't bother with zero or tiny change change_address = fromaddresses[-1] if change_address in outputs: outputs[change_address] += float(change_amount) else: outputs[change_address] = float(change_amount) rawtx = bitcoind.createrawtransaction(inputs, outputs) signed_rawtx = bitcoind.signrawtransaction(rawtx) if not signed_rawtx["complete"]: sys.stderr.write("signrawtransaction failed\n") sys.exit(1) txdata = signed_rawtx["hex"] return txdata def compute_amount_in(bitcoind, txinfo): result = Decimal("0.0") for vin in txinfo['vin']: in_info = bitcoind.getrawtransaction(vin['txid'], 1) vout = in_info['vout'][vin['vout']] result = result + vout['value'] return result def compute_amount_out(txinfo): result = Decimal("0.0") for vout in txinfo['vout']: result = result + vout['value'] return result def sanity_test_fee(bitcoind, txdata_hex, max_fee): class FeeError(RuntimeError): pass try: txinfo = bitcoind.decoderawtransaction(txdata_hex) total_in = compute_amount_in(bitcoind, txinfo) total_out = compute_amount_out(txinfo) if total_in-total_out > max_fee: raise FeeError("Rejecting transaction, unreasonable fee of "+str(total_in-total_out)) tx_size = len(txdata_hex)/2 kb = tx_size/1000 # integer division rounds down if kb > 1 and fee < BASE_FEE: raise FeeError("Rejecting no-fee transaction, larger than 1000 bytes") if total_in < 0.01 and fee < BASE_FEE: raise FeeError("Rejecting no-fee, tiny-amount transaction") # Exercise for the reader: compute transaction priority, and # warn if this is a very-low-priority transaction except FeeError as err: sys.stderr.write((str(err)+"\n")) sys.exit(1) def main(): import optparse parser = optparse.OptionParser(usage="%prog [options]") parser.add_option("--from", dest="fromaddresses", default=None, help="addresses to get bitcoins from") parser.add_option("--to", dest="to", default=None, help="address to get send bitcoins to") parser.add_option("--amount", dest="amount", default=None, help="amount to send") parser.add_option("--fee", dest="fee", default="0.0", help="fee to include") parser.add_option("--datadir", dest="datadir", default=determine_db_dir(), help="location of bitcoin.conf file with RPC username/password (default: %default)") parser.add_option("--testnet", dest="testnet", default=False, action="store_true", help="Use the test network") parser.add_option("--dry_run", dest="dry_run", default=False, action="store_true", help="Don't broadcast the transaction, just create and print the transaction data") (options, args) = parser.parse_args() check_json_precision() config = read_bitcoin_config(options.datadir) if options.testnet: config['testnet'] = True bitcoind = connect_JSON(config) if options.amount is None: address_summary = list_available(bitcoind) for address,info in address_summary.iteritems(): n_transactions = len(info['outputs']) if n_transactions > 1: print("%s %.8f %s (%d transactions)"%(address, info['total'], info['account'], n_transactions)) else: print("%s %.8f %s"%(address, info['total'], info['account'])) else: fee = Decimal(options.fee) amount = Decimal(options.amount) while unlock_wallet(bitcoind) == False: pass # Keep asking for passphrase until they get it right txdata = create_tx(bitcoind, options.fromaddresses.split(","), options.to, amount, fee) sanity_test_fee(bitcoind, txdata, amount*Decimal("0.01")) if options.dry_run: print(txdata) else: txid = bitcoind.sendrawtransaction(txdata) print(txid) if __name__ == '__main__': main()