gistfile1.py

# need 'from bitcoin import *' in the git version of pybitcointools...
from pybitcointools import *

### OPCODES - just the ones we need
OP_NAME_UPDATE = 3
OP_2DROP = 109
OP_DROP = 117
OP_DUP = 118
OP_HASH160 = 169
OP_EQUALVERIFY = 136
OP_CHECKSIG = 172

def name_update_to_script(name, data, addr):
    return serialize_script([
        OP_NAME_UPDATE,
        hexlify(name),
        hexlify(data),
        OP_2DROP, OP_DROP,
        OP_DUP, OP_HASH160,
        b58check_to_hex(addr),
        OP_EQUALVERIFY, OP_CHECKSIG
    ])

def script_to_name_update(script):
    # XXX for now be strict about format
    opcodes = deserialize_script(script)
    name = unhexlify(opcodes[1])
    data = unhexlify(opcodes[2])
    addr = hex_to_b58check(opcodes[7])
    if script == name_update_to_script(name, data, addr):
        return AttrDict({'name':name, 'data':data, 'address':addr})
    else:
        raise ValueError("Malformed NAME_UPDATE script.")

## rpc via bitcoinrpc - it works out of the box with namecoin

def get_last_output(name):
    history = filter(lambda x: 'expired' not in x, _nt['rpc'].name_history(name))
    txid = sorted(history, key=lambda x: x['expires_in'], reverse=True)[0]['txid']
    # we still need the vout
    for output in _nt['rpc'].getrawtransaction(txid, 1)['vout']:
        if 'nameOp' in output['scriptPubKey']:
            if output['scriptPubKey']['nameOp']['name'] == name:
                return AttrDict({
                    'txid': txid,
                    'vout': output['n'],
                    'amount': output['value']
                })
    raise ValueError("Could not find last output for '%s'!" % name)