Blockchain Library for Haskell

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ED/DV: Pavan Ananth Sharma

A blockchain library for haskell.

Reference

Parse a raw bitcoin transaction

Use a haskell library binary to parse.

getTransaction :: Get Transaction

getTransactionFromHexString :: String -> Transaction

Both functions will automatically detect whether the given transaction is segwit format or not.

An example:

import Data.ByteString.Base16.Lazy (encode, decode)
import Data.ByteString.Lazy.Char8 (pack)
import Data.Binary.Get
import Control.Applicative ((<|>))
import ParserUtil
import Transaction

main :: IO ()
main = print $ getTransactionFromHexString "01000000000101....."

See https://github.com/aidatorajiro/blockchain-haskell/blob/master/test/ParseTransactionSpec.hs for test vectors.

Create a raw bitcoin transaction from Transaction

putTransaction :: Transaction -> Put

putTransactionToHexString :: Transaction -> String

Set transactionIsSegwit True to include transactionMarker, transactionFlag and transactionWitness to the output.

An example:

import Data.ByteString.Base16.Lazy (encode, decode)
import Data.ByteString.Lazy.Char8 (pack)
import Data.Binary.Get
import Control.Applicative ((<|>))
import ParserUtil
import Transaction

main :: IO ()
main = print $ putTransactionToHexString $ Transaction {
      transactionIsSegwit = True,
      transactionVersion = 1,
      transactionMarker = Just 0,
      transactionFlag = Just 1,
      transactionTxins = [
        Txin {
          txinHash = decodeHex $ "b04613c21ede2fb0ae2a1e9c28f0ce165df76e927a39cf2ffba9b4573f0a1c91",
          txinIndex = 0,
          txinScript = decodeHex $ "",
          txinSequenceNo = 4294967293
        }
      ],
      transactionTxouts = [
        Txout {
          txoutAmount = 0,
          txoutScript = decodeHex $ "6a14e381a6e38199e381a8e381a0e382882121212121"
        },
        Txout {
          txoutAmount = 39974,
          txoutScript = decodeHex $ "001481eab72a9b738962f178dc833cc56ca9b210151e"
        }
      ],
      transactionLocktime = 550309,
      transactionWitness = Just $ Witness [[decodeHex $ "3044022079cc2e04889802b4623813232fa3075929dab3395f4f7a0f0ab6e032c84412ca02200c8e51fae2a8aa56642f272ccb8655a6e26dc28aa36c5b9e237ee51fa8fff1df01", decodeHex $ "02383da0568d9536aa96c9d0514578c1a75e14c95fee4a9330f1fee7591640e51e"]]
    }

Features

implemented

• Parse a Bitcoin transaction
• Serialize a Bitcoin transaction

not implemented

• Blocks
• Verification
• Signing
• Simulate a Bitcoin system monadically

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