transactions.ts

// This files contain examples on how to use this module. You can run them with ts-node, as this
// project is developed in typescript. Install the dependencies and run `npx ts-node examples/transactions.ts`

import { Transaction } from '../src'

// We create an unsigned transaction.
// Notice we don't set the `to` field because we are creating a new contract.
// This transaction's chain is set to mainnet
const tx = new Transaction({
  nonce: 0,
  gasPrice: 100,
  gasLimit: 1000000000,
  value: 0,
  data:
    '0x7f4e616d65526567000000000000000000000000000000000000000000000000003057307f4e616d6552656700000000000000000000000000000000000000000000000000573360455760415160566000396000f20036602259604556330e0f600f5933ff33560f601e5960003356576000335700604158600035560f602b590033560f60365960003356573360003557600035335700',
})

// We sign the transaction with this private key
const privateKey = new Buffer(
  'e331b6d69882b4cb4ea581d88e0b604039a3de5967688d3dcffdd2270c0fd109',
  'hex',
)
tx.sign(privateKey)

// We have a signed transaction, Now for it to be fully fundable the account that we signed
// it with needs to have a certain amount of wei in to. To see how much this
// account needs we can use the getUpfrontCost() method.
const feeCost = tx.getUpfrontCost()
console.log('Total Amount of wei needed:' + feeCost.toString())

// Lets serialize the transaction

console.log('---Serialized TX----')
console.log(tx.serialize().toString('hex'))
console.log('--------------------')

// Parsing & Validating transactions
// If you have a transaction that you want to verify you can parse it. If you got
// it directly from the network it will be rlp encoded. You can decode it with the rlp
// module. After that you should have something like:
const rawTx = [
  '0x00',
  '0x09184e72a000',
  '0x2710',
  '0x0000000000000000000000000000000000000000',
  '0x00',
  '0x7f7465737432000000000000000000000000000000000000000000000000000000600057',
  '0x1c',
  '0x5e1d3a76fbf824220eafc8c79ad578ad2b67d01b0c2425eb1f1347e8f50882ab',
  '0x5bd428537f05f9830e93792f90ea6a3e2d1ee84952dd96edbae9f658f831ab13',
]

const tx2 = new Transaction(rawTx) // This is also a maninnet transaction

// Note rlp.decode will actually produce an array of buffers `new Transaction` will
// take either an array of buffers or an array of hex strings.
// So assuming that you were able to parse the transaction, we will now get the sender's
// address

console.log('Senders Address: ' + tx2.getSenderAddress().toString('hex'))

// Cool now we know who sent the tx! Lets verify the signature to make sure it was not
// some poser.

if (tx2.verifySignature()) {
  console.log('Signature Checks out!')
}

// And hopefully its verified. For the transaction to be totally valid we would
// also need to check the account of the sender and see if they have enough funds.