def tx(self, txid):
"""
Get the MsgTx. Retreive it from the blockchain if necessary.
Args:
txid (str): A hex encoded transaction ID to fetch.
Returns:
MsgTx: The transaction.
"""
hashKey = hashFromHex(txid).bytes()
with self.txDB as txDB:
try:
encoded = ByteArray(txDB[hashKey])
return msgtx.MsgTx.deserialize(encoded)
except database.NoValue:
try:
# Grab the hex encoded transaction
txHex = self.dcrdata.tx.hex(txid)
if not txHex:
raise Exception(
"failed to retrieve tx hex from dcrdata")
encoded = ByteArray(txHex)
txDB[hashKey] = encoded.bytes()
return msgtx.MsgTx.deserialize(encoded)
except:
log.warning(
"unable to retrieve tx data from dcrdata at %s" %
self.dcrdata.baseUri)
raise Exception("failed to reteive transaction")
def __init__(self, pw):
"""
Args:
pw (byte-like): A password that deterministically generates the key.
"""
super().__init__()
salt = ByteArray(generateSeed(KEY_SIZE))
b = lambda v: ByteArray(v).bytes()
func, hashName, iterations = defaultKDFParams()
self.key = ByteArray(
hashlib.pbkdf2_hmac(hashName, b(pw), salt.bytes(), iterations))
digest = ByteArray(hashlib.sha256(self.key.b).digest())
self.keyParams = KDFParams(salt, digest)
def string(self):
"""
string returns the extended key as a base58-encoded string. See
`decodeExtendedKey` for decoding.
Returns:
str: The encoded extended key.
"""
if self.key.iszero():
raise ZeroBytesError("unexpected zero key")
childNumBytes = ByteArray(self.childNum, length=4)
depthByte = ByteArray(self.depth % 256, length=1)
# The serialized format is:
# version (4) || depth (1) || parent fingerprint (4)) ||
# child num (4) || chain code (32) || key data (33) || checksum (4)
serializedBytes = ByteArray(
bytearray(0)) # length serializedKeyLen + 4 after appending
if self.isPrivate:
serializedBytes += self.privVer
else:
serializedBytes += self.pubVer
serializedBytes += depthByte
serializedBytes += self.parentFP
serializedBytes += childNumBytes
serializedBytes += self.chainCode
if self.isPrivate:
serializedBytes += bytearray(1)
serializedBytes += self.key
else:
serializedBytes += self.pubKey
checkSum = checksum(serializedBytes.b)[:4]
serializedBytes += checkSum
return b58encode(serializedBytes.bytes()).decode()