Module: Solana::Ruby::Kit::OffchainMessages::Codec

Extended by:
T::Sig
Defined in:
lib/solana/ruby/kit/offchain_messages/codec.rb

Overview

Wire format for off-chain messages (Solana standard).

v0: [0xFF, 0xFF] + domain_len(u8) + domain + version(u8) + message_len(u16LE) + message v1: [0xFF, 0xFF] + domain_len(u8) + domain + version(u8) + app_domain_len(u16LE) + app_domain + message_len(u16LE) + message

Constant Summary collapse

MAGIC = 
T.let("\xFF\xFF".b.freeze, String)

Class Method Summary collapse

Class Method Details

.decode_offchain_message(bytes) ⇒ Object

rubocop:disable Metrics/MethodLength



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# File 'lib/solana/ruby/kit/offchain_messages/codec.rb', line 53

def decode_offchain_message(bytes) # rubocop:disable Metrics/MethodLength
  b = bytes.b
  Kernel.raise SolanaError.new(SolanaError::OFFCHAIN_MESSAGES__INVALID_MESSAGE_FORMAT) unless b.byteslice(0, 2) == MAGIC

  offset     = 2
  domain_len = b.byteslice(offset, 1)&.unpack1('C') || 0
  offset    += 1
  domain     = b.byteslice(offset, domain_len)&.force_encoding('ASCII') || ''
  offset    += domain_len
  version    = b.byteslice(offset, 1)&.unpack1('C') || 0
  offset    += 1

  application_domain = nil
  if version >= 1
    app_len = b.byteslice(offset, 2)&.unpack1('v') || 0
    offset += 2
    # A zero length means there was no application domain, not an empty one, so
    # that encode/decode round-trips a message that never had one.
    application_domain = app_len.positive? ? b.byteslice(offset, app_len)&.force_encoding('ASCII') : nil
    offset += app_len
  end

  msg_len = b.byteslice(offset, 2)&.unpack1('v') || 0
  offset += 2
  message = b.byteslice(offset, msg_len)&.force_encoding('UTF-8') || ''

  Message.new(
    version:            version,
    domain:             domain,
    message:            message,
    application_domain: application_domain
  )
end

.encode_offchain_message(msg) ⇒ Object 



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# File 'lib/solana/ruby/kit/offchain_messages/codec.rb', line 22

def encode_offchain_message(msg)
  domain_b = msg.domain.encode('ASCII').b
  Kernel.raise ArgumentError, 'Domain exceeds 255 bytes' if domain_b.bytesize > 255

  message_b = msg.message.encode('UTF-8').b
  Kernel.raise ArgumentError, 'Message too large' if message_b.bytesize > 0xFFFF

  buf = MAGIC.dup
  buf << [domain_b.bytesize].pack('C')
  buf << domain_b
  buf << [msg.version].pack('C')

  # The v1 application-domain block is always emitted, using a zero length when
  # there is no application domain. The decoder reads this length unconditionally
  # for v1, so omitting the block would desynchronise it and make it read the
  # message length as an application-domain length.
  if msg.version >= 1
    app_b = msg.application_domain ? T.must(msg.application_domain).encode('ASCII').b : ''.b
    Kernel.raise ArgumentError, 'Application domain exceeds 65535 bytes' if app_b.bytesize > 0xFFFF

    buf << [app_b.bytesize].pack('v')
    buf << app_b
  end

  buf << [message_b.bytesize].pack('v')
  buf << message_b
  buf.b
end

.sign_offchain_message(signer, msg) ⇒ Object 



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# File 'lib/solana/ruby/kit/offchain_messages/codec.rb', line 89

def sign_offchain_message(signer, msg)
  payload = encode_offchain_message(msg)
  Keys.encode_signature(signer.sign(payload))
end

.verify_offchain_message_signature(verify_key, signature, msg) ⇒ Object 



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# File 'lib/solana/ruby/kit/offchain_messages/codec.rb', line 102

def verify_offchain_message_signature(verify_key, signature, msg)
  payload = encode_offchain_message(msg)
  vk      = RbNaCl::VerifyKey.new(verify_key)
  # `Signature` holds a base58 string (that is what `sign_offchain_message` returns),
  # so it has to be decoded back to the 64 raw bytes RbNaCl expects.
  sig_bytes = Solana::Ruby::Kit::Encoding::Base58.decode(signature.to_s)
  vk.verify(sig_bytes, payload)
  true
rescue RbNaCl::BadSignatureError, RbNaCl::LengthError
  false
end