Bitcoin Transaction: Python parsing library

KS implementation details

License: MIT

This page hosts a formal specification of Bitcoin Transaction using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for Python generated by Kaitai Struct depends on the Python runtime library. You have to install it before you can parse data.

The Python runtime library can be installed from PyPI:

python3 -m pip install kaitaistruct

Code

Parse a local file and get structure in memory:

data = BitcoinTransaction.from_file("path/to/local/file.bin")

Or parse structure from a bytes:

from kaitaistruct import KaitaiStream, BytesIO

raw = b"\x00\x01\x02..."
data = BitcoinTransaction(KaitaiStream(BytesIO(raw)))

After that, one can get various attributes from the structure by invoking getter methods like:

data.version # => Version number.

Python source code to parse Bitcoin Transaction

bitcoin_transaction.py

# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
# type: ignore

import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO
from enum import IntEnum


if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 11):
    raise Exception("Incompatible Kaitai Struct Python API: 0.11 or later is required, but you have %s" % (kaitaistruct.__version__))

class BitcoinTransaction(KaitaiStruct):
    """
    .. seealso::
       Source - https://bitcoin.org/en/developer-guide#transactions
       https://en.bitcoin.it/wiki/Transaction
    """
    def __init__(self, _io, _parent=None, _root=None):
        super(BitcoinTransaction, self).__init__(_io)
        self._parent = _parent
        self._root = _root or self
        self._read()

    def _read(self):
        self.version = self._io.read_u4le()
        self.num_vins = self._io.read_u1()
        self.vins = []
        for i in range(self.num_vins):
            self.vins.append(BitcoinTransaction.Vin(self._io, self, self._root))

        self.num_vouts = self._io.read_u1()
        self.vouts = []
        for i in range(self.num_vouts):
            self.vouts.append(BitcoinTransaction.Vout(self._io, self, self._root))

        self.locktime = self._io.read_u4le()


    def _fetch_instances(self):
        pass
        for i in range(len(self.vins)):
            pass
            self.vins[i]._fetch_instances()

        for i in range(len(self.vouts)):
            pass
            self.vouts[i]._fetch_instances()


    class Vin(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(BitcoinTransaction.Vin, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.txid = self._io.read_bytes(32)
            self.output_id = self._io.read_u4le()
            self.len_script = self._io.read_u1()
            self._raw_script_sig = self._io.read_bytes(self.len_script)
            _io__raw_script_sig = KaitaiStream(BytesIO(self._raw_script_sig))
            self.script_sig = BitcoinTransaction.Vin.ScriptSignature(_io__raw_script_sig, self, self._root)
            self.end_of_vin = self._io.read_bytes(4)
            if not self.end_of_vin == b"\xFF\xFF\xFF\xFF":
                raise kaitaistruct.ValidationNotEqualError(b"\xFF\xFF\xFF\xFF", self.end_of_vin, self._io, u"/types/vin/seq/4")


        def _fetch_instances(self):
            pass
            self.script_sig._fetch_instances()

        class ScriptSignature(KaitaiStruct):

            class SighashType(IntEnum):
                sighash_all = 1
                sighash_none = 2
                sighash_single = 3
                sighash_anyonecanpay = 80
            def __init__(self, _io, _parent=None, _root=None):
                super(BitcoinTransaction.Vin.ScriptSignature, self).__init__(_io)
                self._parent = _parent
                self._root = _root
                self._read()

            def _read(self):
                self.len_sig_stack = self._io.read_u1()
                self.der_sig = BitcoinTransaction.Vin.ScriptSignature.DerSignature(self._io, self, self._root)
                self.sig_type = KaitaiStream.resolve_enum(BitcoinTransaction.Vin.ScriptSignature.SighashType, self._io.read_u1())
                self.len_pubkey_stack = self._io.read_u1()
                self.pubkey = BitcoinTransaction.Vin.ScriptSignature.PublicKey(self._io, self, self._root)


            def _fetch_instances(self):
                pass
                self.der_sig._fetch_instances()
                self.pubkey._fetch_instances()

            class DerSignature(KaitaiStruct):
                def __init__(self, _io, _parent=None, _root=None):
                    super(BitcoinTransaction.Vin.ScriptSignature.DerSignature, self).__init__(_io)
                    self._parent = _parent
                    self._root = _root
                    self._read()

                def _read(self):
                    self.sequence = self._io.read_bytes(1)
                    if not self.sequence == b"\x30":
                        raise kaitaistruct.ValidationNotEqualError(b"\x30", self.sequence, self._io, u"/types/vin/types/script_signature/types/der_signature/seq/0")
                    self.len_sig = self._io.read_u1()
                    self.sep_1 = self._io.read_bytes(1)
                    if not self.sep_1 == b"\x02":
                        raise kaitaistruct.ValidationNotEqualError(b"\x02", self.sep_1, self._io, u"/types/vin/types/script_signature/types/der_signature/seq/2")
                    self.len_sig_r = self._io.read_u1()
                    self.sig_r = self._io.read_bytes(self.len_sig_r)
                    self.sep_2 = self._io.read_bytes(1)
                    if not self.sep_2 == b"\x02":
                        raise kaitaistruct.ValidationNotEqualError(b"\x02", self.sep_2, self._io, u"/types/vin/types/script_signature/types/der_signature/seq/5")
                    self.len_sig_s = self._io.read_u1()
                    self.sig_s = self._io.read_bytes(self.len_sig_s)


                def _fetch_instances(self):
                    pass


            class PublicKey(KaitaiStruct):
                def __init__(self, _io, _parent=None, _root=None):
                    super(BitcoinTransaction.Vin.ScriptSignature.PublicKey, self).__init__(_io)
                    self._parent = _parent
                    self._root = _root
                    self._read()

                def _read(self):
                    self.type = self._io.read_u1()
                    self.x = self._io.read_bytes(32)
                    self.y = self._io.read_bytes(32)


                def _fetch_instances(self):
                    pass




    class Vout(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(BitcoinTransaction.Vout, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.amount = self._io.read_u8le()
            self.len_script = self._io.read_u1()
            self.script_pub_key = self._io.read_bytes(self.len_script)


        def _fetch_instances(self):
            pass