user-guide.md

User Guide

All information for developers using ethjs-signer should consult this document.

Install

npm install --save ethjs-signer

Usage

const HttpProvider = require('ethjs-provider-http');
const Eth = require('ethjs-query');
const eth = new Eth(HttpProvider('http://localhost:8545'));
const sign = require('ethjs-signer');

const address = '0x0F6af8F8D7AAD198a7607C96fb74Ffa02C5eD86B';
const privateKey = '0xecbcd9838f7f2afa6e809df8d7cdae69aa5dfc14d563ee98e97effd3f6a652f2';

eth.getTransactionCount(address).then((nonce) => {
  eth.sendRawTransaction(sign({
    to: '0xcG31a19193d4b23f4e9d6163d7247243bAF801c3',
    value: 300000,
    gas: new BN('43092000'),
    nonce: nonce,
  }, privateKey)).then((txHash) => {
    console.log('Transaction Hash', txHash);
  });
});

API Design

sign

index.js:ethjs-signer

Intakes a raw transaction object and private key, outputs either a signed transaction hex string (by default) or a raw signed array of Buffer values (if specified). The hexified string payload can be used in conjunction with methods like eth_sendRawTransaction.

Parameters

• rawTransaction Object - a single raw transaction object.
• privateKey String - a single 32 byte prefixed hex string that is a Ethereum standard private key
• toArray Boolean (optional) - return the signed payload in its raw array format

Result output signed tx payload String|Object.

const sign = require('ethjs-signer').sign;

console.log(sign({ gas: 300000, data: '0x' }, '0x..privte key'));

// result '0x.....'

console.log(sign({ from: '0x..', gas: '0x...', data: '0x' }, '0x..privte key', true));

// result [ <Buffer...>, <Buffer ...>, <Buffer ...> ...]

recover

index.js:ethjs-signer

Intakes a rawTransaction hex string or Buffer instance, the recovery param (Number), and the transaction signature r (Buffer) and s (Buffer) values. Returns the public key as a Buffer instance for the signers account.

Parameters

• rawTransaction String|Buffer - the raw transaction either as a hex string or Buffer instance
• v Number - the recovery param
• r Buffer - the signature 'r' value
• s Buffer - the signature 's' value

Result output public key Buffer.

const recover = require('ethjs-signer').recover;
const sign = require('ethjs-signer').sign;
const stripHexPrefix = require('strip-hex-prefix');
const generate = require('ethjs-account').generate;
const publicToAddress = require('ethjs-account').publicToAddress;

const testAccount = generate('sdkjfhskjhskhjsfkjhsf093j9sdjfpisjdfoisjdfisdfsfkjhsfkjhskjfhkshdf');
const rawTx = {
  to: testAccount.address.toLowerCase(),
  nonce: `0x${new BN(0).toString(16)}`,
  gasPrice: `0x${new BN(0).toString(16)}`,
  gasLimit: `0x${new BN(0).toString(16)}`,
  value: `0x${new BN(0).toString(16)}`,
  data: '0x',
};
const signedTx = sign(rawTx, testAccount.privateKey, true);
const signedTxBuffer = new Buffer(stripHexPrefix(sign(rawTx, testAccount.privateKey)), 'hex');
const publicKey = recover(signedTxBuffer,
  (new BN(signedTx[6].toString('hex'), 16).toNumber(10)),
  signedTx[7],
  signedTx[8]);
const address = publicToAddress(publicKey);

if (address == testAccount.address) {
  console.log('Recovery success!');
}

Browser Builds

ethjs provides production distributions for all of its modules that are ready for use in the browser right away. Simply include either dist/ethjs-signer.js or dist/ethjs-signer.min.js directly into an HTML file to start using this module. Note, an ethSigner object is made available globally.

<script type="text/javascript" src="ethjs-signer.min.js"></script>
<script type="text/javascript">
ethSigner(...);
</script>

Note, even though ethjs should have transformed and polyfilled most of the requirements to run this module across most modern browsers. You may want to look at an additional polyfill for extra support.

Use a polyfill service such as Polyfill.io to ensure complete cross-browser support: https://polyfill.io/

Latest Webpack Figures

Version: webpack 2.1.0-beta.15
Time: 1756ms
              Asset    Size  Chunks             Chunk Names
    ethjs-signer.js  361 kB       0  [emitted]  main
ethjs-signer.js.map  443 kB       0  [emitted]  main
  [44] multi main 28 bytes {0} [built]
    + 44 hidden modules
                
Version: webpack 2.1.0-beta.15
Time: 7583ms
              Asset    Size  Chunks             Chunk Names
ethjs-signer.min.js  181 kB       0  [emitted]  main
  [44] multi main 28 bytes {0} [built]
    + 44 hidden modules

Other Awesome Modules, Tools and Frameworks

Foundation

• web3.js -- the original Ethereum JS swiss army knife Ethereum Foundation
• ethereumjs -- critical ethereum javascript infrastructure Ethereum Foundation
• browser-solidity -- an in browser Solidity IDE Ethereum Foundation

Nodes

• geth Go-Ethereum
• parity Rust-Ethereum build in Rust
• testrpc Testing Node (ethereumjs-vm)

Testing

• wafr -- a super simple Solidity testing framework
• truffle -- a solidity/js dApp framework
• embark -- a solidity/js dApp framework
• dapple -- a solidity dApp framework
• chaitherium -- a JS web3 unit testing framework
• contest -- a JS testing framework for contracts

Wallets

• ethers-wallet -- an amazingly small Ethereum wallet
• metamask -- turns your browser into an Ethereum enabled browser =D

Our Relationship with Ethereum & EthereumJS

We would like to mention that we are not in any way affiliated with the Ethereum Foundation or ethereumjs. However, we love the work they do and work with them often to make Ethereum great! Our aim is to support the Ethereum ecosystem with a policy of diversity, modularity, simplicity, transparency, clarity, optimization and extensibility.

Many of our modules use code from web3.js and the ethereumjs- repositories. We thank the authors where we can in the relevant repositories. We use their code carefully, and make sure all test coverage is ported over and where possible, expanded on.

A Special Thanks

A special thanks to Richard Moore for building ethers-wallet and other amazing things. Aaron Davis (@kumavis) for his guidence.