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transactionBuilder.md

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TransactionBuilder

constructor

Create new Transaction Builder. The Transaction Builder object represents a transaction internally and is used to build a transaction step-by-step. It can then be expressed as a hexadecimal string ready to be sent to the $BCH network. The necessary steps to create a transaction are: addInput, addOutput, setLockTime, sign and build.

Arguments

  1. network string: Defaults to "mainnet"

Result

TransactionBuilder TransactionBuilder

Examples

  // instance of transaction builder
  let transactionBuilder = new bitbox.TransactionBuilder('mainnet');

hashTypes

BITBOX supports the SIGHASH_ALL, SIGHASH_NONE and SIGHASH_SINGLE hash types w/ the SIGHASH_ANYONECANPAY modifier.

Examples

  transactionBuilder.hashTypes
  // { SIGHASH_ALL: 1,
  //   SIGHASH_NONE: 2,
  //   SIGHASH_SINGLE: 3,
  //   SIGHASH_ANYONECANPAY: 128,
  //   SIGHASH_BITCOINCASH_BIP143: 64 }

  transactionBuilder.hashTypes.SIGHASH_ALL
  // 1

  // also has a DEFAULT_SEQUENCE of 0xffffffff
  transactionBuilder.DEFAULT_SEQUENCE
  // 4294967295

signatureAlgorithms

BITBOX supports the ECDSA and SCHNORR signature algorithms.

Examples

  transactionBuilder.signatureAlgorithms
  // { ECDSA: 0,
  //   SCHNORR: 1 }

addInput

Add input to transaction

Arguments

  1. txid string: txid of vout
  2. index number: index of vout
  3. sequence number optional: relative lock time. Default 0xffffffff
  4. prevOutScript string optional: previous output script

Examples

  // txid of vout
  let txid = 'f7890915febe580920df2681d2bac0909ae89bd0cc1d3ed763e5eeba7f337f0e';
  // add input with txid and index of vout
  transactionBuilder.addInput(txid, 0);

addOutput

Add output to transaction

Arguments

  1. scriptPubKey string: legacy/cashaddr address or script
  2. sendAmount number: amount to send in satoshis

Examples

  let originalAmount = 100000;
  let byteCount = bitbox.BitcoinCash.getByteCount({ P2PKH: 1 }, { P2PKH: 1 });
  // amount to send to receiver. It's the original amount - 1 sat/byte for tx size
  let sendAmount = originalAmount - byteCount;
  // add output w/ address and amount to send
  transactionBuilder.addOutput('bitcoincash:qpuax2tarq33f86wccwlx8ge7tad2wgvqgjqlwshpw', sendAmount);

setLockTime

Set locktime

Arguments

  1. locktime number

Examples

  let originalAmount = 100000;
  let byteCount = bitbox.BitcoinCash.getByteCount({ P2PKH: 1 }, { P2PKH: 1 });
  // amount to send to receiver. It's the original amount - 1 sat/byte for tx size
  let sendAmount = originalAmount - byteCount;
  // add output w/ address and amount to send
  transactionBuilder.addOutput('bitcoincash:qpuax2tarq33f86wccwlx8ge7tad2wgvqgjqlwshpw', sendAmount);
  transactionBuilder.setLockTime(50000)

sign

Sign transaction. It creates the unlocking script needed to spend an input. Each input has its own script and thus 'sign' must be called for each input even if the keyPair is the same.

Arguments

  1. vin number: vin to sign
  2. keyPair ECPair: ECPair of HDNode
  3. redeemScript Buffer
  4. hashType number
  5. originalAmount number: satoshis in vin
  6. signatureAlgorithm optional number: Signature Algorithm (ECDSA/Schnorr)

Examples

  let originalAmount = 100000;
  // node of address which is going to spend utxo
  let hdnode = bitbox.HDNode.fromXPriv("xprvA3eaDg64MwDr72PVGJ7CkvshNAzCDRz7rn98sYrZVAtDSWCAmNGQhEQeCLDcnmcpSkfjhHevXmu4ZL8ZcT9D4vEbG8LpiToZETrHZttw9Yw");
  // keypair
  let keyPair = bitbox.HDNode.toKeyPair(hdnode);
  // empty redeemScript variable
  let redeemScript;
  // sign w/ keyPair
  transactionBuilder.sign(0, keyPair, redeemScript, transactionBuilder.hashTypes.SIGHASH_ALL, originalAmount, transactionBuilder.signatureAlgorithms.SCHNORR);

build

Build transaction

Result

Transaction Object: Transaction

Examples

  // build tx
  let tx = transactionBuilder.build();

toHex

Return raw hex of transaction ready to be sent to the $BCH network

Result

rawHex string: hex encoded raw transaction ready to be sent to the $BCH network

Examples

  // output rawhex
  let hex = tx.toHex();
  // 02000000010e7f337fbaeee563d73e1dccd09be89a90c0bad28126df200958befe150989f7000000006b48304502210085b8eb33f3981315bbe39c6810d0311c6cb39504914300ecd952cab8353222e202200ec95797c06ba8c9b15d59ab80e63300cb2371f67b3969d0b502d0fed733fbed4121025c85a571619e60fed412de0356b4e28f4f3670ab0c2b899dfe60e69aaa6cd4c0ffffffff01a6370000000000001976a91479d3297d1823149f4ec61df31d19f2fad5390c0288ac00000000
  // sendRawTransaction to running BCH node
  bitbox.RawTransactions.sendRawTransaction(hex).then((result) => { console.log(result); }, (err) => { console.log(err); });
  // dfe54ec45c6fa2fa85b76d113de85b169d36902eaf6700f1cca21eed1392814b

OP_RETURN

Write data to the blockchain w/ OP_RETURN

Result

rawHex string: hex encoded raw transaction ready to be sent to the $BCH network

Examples

  // encode some text as a buffer
  let buf = new Buffer('#BCHForEveryone');
  // create array w/ OP_RETURN code and text buffer and encode
  let data = bitbox.Script.encode([
  bitbox.Script.opcodes.OP_RETURN,
  buf
  ])
  // add encoded data as output and send 0 satoshis
  transactionBuilder.addOutput(data, 0)

  // later when you decode the raw hex of the tx you'll see this scriptPubKey
  "OP_RETURN 23424348466f7245766572796f6e65"

  // you can use BITBOX to decode it to the original text
  let fromAsm = bitbox.Script.fromASM("OP_RETURN 23424348466f7245766572796f6e65")
  let decoded = bitbox.Script.decode(fromAsm)
  decoded[1].toString('ascii')
  // #BCHForEveryone

bip66.encode

Strict DER signature encoding per bip66

Arguments

  1. r Buffer
  2. s Buffer

Result

encoded Buffer

Examples

  let transactionBuilder = new bitbox.TransactionBuilder();
  let r = Buffer.from('1ea1fdff81b3a271659df4aad19bc4ef83def389131a36358fe64b245632e777', 'hex');
  let s = Buffer.from('29e164658be9ce810921bf81d6b86694785a79ea1e52dbfa5105148d1f0bc1', 'hex');
  transactionBuilder.bip66.encode(r, s);
  //

bip66.decode

Strict DER signature decoding per bip66

Arguments

  1. signature Buffer

Result

decoded Object

Examples

  let transactionBuilder = new bitbox.TransactionBuilder();
  let signature = new Buffer.from('304302201ea1fdff81b3a271659df4aad19bc4ef83def389131a36358fe64b245632e777021f29e164658be9ce810921bf81d6b86694785a79ea1e52dbfa5105148d1f0bc1', 'hex');
  transactionBuilder.bip66.decode(signature);
  // { r:
  //  ,
  // s:
  //   }

bip66.check

Check format of bip66 Strict DER Signature

Arguments

  1. DER Buffer

Result

value boolean

Examples

  let transactionBuilder = new bitbox.TransactionBuilder();
  let DER = '3044022029db2d5f4e1dcc04e19266cce3cb135865784c62ab653b307f0e0bb744f5c2aa022000a97f5826912cac8b44d9f577a26f169a2f8db781f2ddb7de2bc886e93b6844';
  let buffer = Buffer.from(DER, 'hex')
  transactionBuilder.bip66.check(buffer);
  // true

bip68.encode

Encoded bip68 relative time lock

Arguments

  1. config Object: Valid keys: seconds and block. seconds must be in multiples of 512.

Result

hex string: hex encoded relative timelock

Examples

  let transactionBuilder = new bitbox.TransactionBuilder();
  transactionBuilder.bip68.encode({ seconds: 2048 })
  // 4194308
  transactionBuilder.bip68.encode({ blocks: 52 })
  // 52

bip68.decode

Decoded bip68 relative time lock

Arguments

  1. hex string: hex encoded relative lock time

Result

details Object: details about the relative lock time

Examples

  let transactionBuilder = new bitbox.TransactionBuilder();
  transactionBuilder.bip68.decode(0x03ffffff)
  // { seconds: 33553920 }
  transactionBuilder.bip68.decode(0x0100fffe)
  // { blocks: 65534 }