Bitcoin Transaction: Ruby 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 Ruby generated by Kaitai Struct depends on the Ruby runtime library. You have to install it before you can parse data.

The Ruby runtime library can be installed from RubyGems:

gem install kaitai-struct

Code

Parse a local file and get structure in memory:

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

Or parse structure from a string of bytes:

bytes = "\x00\x01\x02..."
data = BitcoinTransaction.new(Kaitai::Struct::Stream.new(bytes))

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

data.version # => Version number.

Ruby source code to parse Bitcoin Transaction

bitcoin_transaction.rb

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

require 'kaitai/struct/struct'

unless Gem::Version.new(Kaitai::Struct::VERSION) >= Gem::Version.new('0.9')
  raise "Incompatible Kaitai Struct Ruby API: 0.9 or later is required, but you have #{Kaitai::Struct::VERSION}"
end


##
# @see https://bitcoin.org/en/developer-guide#transactions
#   https://en.bitcoin.it/wiki/Transaction
#    Source
class BitcoinTransaction < Kaitai::Struct::Struct
  def initialize(_io, _parent = nil, _root = self)
    super(_io, _parent, _root)
    _read
  end

  def _read
    @version = @_io.read_u4le
    @num_vins = @_io.read_u1
    @vins = Array.new(num_vins)
    (num_vins).times { |i|
      @vins[i] = Vin.new(@_io, self, @_root)
    }
    @num_vouts = @_io.read_u1
    @vouts = Array.new(num_vouts)
    (num_vouts).times { |i|
      @vouts[i] = Vout.new(@_io, self, @_root)
    }
    @locktime = @_io.read_u4le
    self
  end
  class Vin < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @txid = @_io.read_bytes(32)
      @output_id = @_io.read_u4le
      @len_script = @_io.read_u1
      @_raw_script_sig = @_io.read_bytes(len_script)
      _io__raw_script_sig = Kaitai::Struct::Stream.new(@_raw_script_sig)
      @script_sig = ScriptSignature.new(_io__raw_script_sig, self, @_root)
      @end_of_vin = @_io.read_bytes(4)
      raise Kaitai::Struct::ValidationNotEqualError.new([255, 255, 255, 255].pack('C*'), end_of_vin, _io, "/types/vin/seq/4") if not end_of_vin == [255, 255, 255, 255].pack('C*')
      self
    end
    class ScriptSignature < Kaitai::Struct::Struct

      SIGHASH_TYPE = {
        1 => :sighash_type_sighash_all,
        2 => :sighash_type_sighash_none,
        3 => :sighash_type_sighash_single,
        80 => :sighash_type_sighash_anyonecanpay,
      }
      I__SIGHASH_TYPE = SIGHASH_TYPE.invert
      def initialize(_io, _parent = nil, _root = self)
        super(_io, _parent, _root)
        _read
      end

      def _read
        @len_sig_stack = @_io.read_u1
        @der_sig = DerSignature.new(@_io, self, @_root)
        @sig_type = Kaitai::Struct::Stream::resolve_enum(SIGHASH_TYPE, @_io.read_u1)
        @len_pubkey_stack = @_io.read_u1
        @pubkey = PublicKey.new(@_io, self, @_root)
        self
      end
      class DerSignature < Kaitai::Struct::Struct
        def initialize(_io, _parent = nil, _root = self)
          super(_io, _parent, _root)
          _read
        end

        def _read
          @sequence = @_io.read_bytes(1)
          raise Kaitai::Struct::ValidationNotEqualError.new([48].pack('C*'), sequence, _io, "/types/vin/types/script_signature/types/der_signature/seq/0") if not sequence == [48].pack('C*')
          @len_sig = @_io.read_u1
          @sep_1 = @_io.read_bytes(1)
          raise Kaitai::Struct::ValidationNotEqualError.new([2].pack('C*'), sep_1, _io, "/types/vin/types/script_signature/types/der_signature/seq/2") if not sep_1 == [2].pack('C*')
          @len_sig_r = @_io.read_u1
          @sig_r = @_io.read_bytes(len_sig_r)
          @sep_2 = @_io.read_bytes(1)
          raise Kaitai::Struct::ValidationNotEqualError.new([2].pack('C*'), sep_2, _io, "/types/vin/types/script_signature/types/der_signature/seq/5") if not sep_2 == [2].pack('C*')
          @len_sig_s = @_io.read_u1
          @sig_s = @_io.read_bytes(len_sig_s)
          self
        end
        attr_reader :sequence
        attr_reader :len_sig
        attr_reader :sep_1

        ##
        # 'r' value's length.
        attr_reader :len_sig_r

        ##
        # 'r' value of the ECDSA signature.
        # @see https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm Source
        attr_reader :sig_r
        attr_reader :sep_2

        ##
        # 's' value's length.
        attr_reader :len_sig_s

        ##
        # 's' value of the ECDSA signature.
        # @see https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm Source
        attr_reader :sig_s
      end
      class PublicKey < Kaitai::Struct::Struct
        def initialize(_io, _parent = nil, _root = self)
          super(_io, _parent, _root)
          _read
        end

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

        ##
        # 'x' coordinate of the public key on the elliptic curve.
        attr_reader :x

        ##
        # 'y' coordinate of the public key on the elliptic curve.
        attr_reader :y
      end
      attr_reader :len_sig_stack

      ##
      # DER-encoded ECDSA signature.
      # @see https://en.wikipedia.org/wiki/X.690#DER_encoding
      #   https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm
      #    Source
      attr_reader :der_sig

      ##
      # Type of signature.
      attr_reader :sig_type
      attr_reader :len_pubkey_stack

      ##
      # Public key (bitcoin address of the recipient).
      attr_reader :pubkey
    end

    ##
    # Previous transaction hash.
    attr_reader :txid

    ##
    # ID indexing an ouput of the transaction refered by txid.
    # This output will be used as an input in the present transaction.
    attr_reader :output_id

    ##
    # ScriptSig's length.
    attr_reader :len_script

    ##
    # ScriptSig.
    # @see https://en.bitcoin.it/wiki/Transaction#Input
    #   https://en.bitcoin.it/wiki/Script
    #    Source
    attr_reader :script_sig

    ##
    # Magic number indicating the end of the current input.
    attr_reader :end_of_vin
    attr_reader :_raw_script_sig
  end
  class Vout < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

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

    ##
    # Number of Satoshis to be transfered.
    attr_reader :amount

    ##
    # ScriptPubKey's length.
    attr_reader :len_script

    ##
    # ScriptPubKey.
    # @see https://en.bitcoin.it/wiki/Transaction#Output
    #   https://en.bitcoin.it/wiki/Script
    #    Source
    attr_reader :script_pub_key
  end

  ##
  # Version number.
  attr_reader :version

  ##
  # Number of input transactions.
  attr_reader :num_vins

  ##
  # Input transactions.
  # An input refers to an output from a previous transaction.
  attr_reader :vins

  ##
  # Number of output transactions.
  attr_reader :num_vouts

  ##
  # Output transactions.
  attr_reader :vouts
  attr_reader :locktime
end