@meterio/devkit NPM

Meter DevKit

Typescript library to aid DApp development on Meter

Installation

npm i --save @meterio/devkit

Usage

import all components or some of them

import { cry, abi, RLP, Transaction, Certificate, Bloom, ScriptEngine } from '@meterio/devkit';

Crypto methods

they are under cry namespace

Hashing

let hash = cry.blake2b256('hello world');
console.log(hash.toString('hex'));
// 256c83b297114d201b30179f3f0ef0cace9783622da5974326b436178aeef610

hash = cry.keccak256('hello world');
console.log(hash.toString('hex'));
// 47173285a8d7341e5e972fc677286384f802f8ef42a5ec5f03bbfa254cb01fad

Secp256k1

let privKey = cry.secp256k1.generatePrivateKey();
let pubKey = cry.secp256k1.derivePublicKey(privKey);
let addr = cry.publicKeyToAddress(pubKey);
let signature = cry.secp256k1.sign(cry.keccak256('hello world'), privKey);
let recoveredPubKey = cry.secp256k1.recover(cry.keccak256('hello world'), signature);

Mnemonic & Keystore

// generate BIP39 mnemonic words, default to 12 words(128bit strength)
let words = cry.mnemonic.generate();

// derive private key from mnemonic words according to BIP32, using the path `m/44'/818'/0'/0`.
// defined for VET at https://github.com/satoshilabs/slips/blob/master/slip-0044.md
let privateKey = cry.mnemonic.derivePrivateKey(words);

// in recovery process, validation is recommended
let ok = cry.mnemonic.validate(words);

// encrypt/decrypt private key using Ethereum's keystore scheme
let keystore = await cry.Keystore.encrypt(privateKey, 'your password');

// throw for wrong password
let recoveredPrivateKey = await cry.Keystore.decrypt(keystore, 'your password');

// roughly check keystore format
ok = cry.Keystore.wellFormed(keystore);

RLP

// define the profile for tx clause structure
let profile: RLP.Profile = {
  name: 'clause',
  kind: [
    { name: 'to', kind: new RLP.NullableFixedBlobKind(20) },
    { name: 'value', kind: new RLP.NumericKind(32) },
    { name: 'data', kind: new RLP.BlobKind() },
  ],
};

let clause = {
  to: '0x7567d83b7b8d80addcb281a71d54fc7b3364ffed',
  value: 10,
  data: '0x',
};

let rlp = new RLP(profile);

let data = rlp.encode(clause);
console.log(data.toString('hex'));
// d7947567d83b7b8d80addcb281a71d54fc7b3364ffed0a80

let obj = rlp.decode(data);
// `obj` should be identical to `clause`

ScriptEngine

Encode

// get script data for staking candidate
const scriptDataBuffer = ScriptEngine.getCandidateData(
  ScriptEngine.Option.OneWeekLock,
  '0x7567d83b7b8d80addcb281a71d54fc7b3364ffed',
  'tester', // candidateName
  'BKjr6wO34Vif9oJHK1/AbMCLHVpvJui3Nx3hLwuOfzwx1Th4H4G0I4liGEC3qKsf8KOd078gYFTK+41n+KhDTzk=:::uH2sc+WgsrxPs91LBy8pIBEjM5I7wNPtSwRSNa83wo4V9iX3RmUmkEPq1QRv4wwRbosNO1RFJ/r64bwdSKK1VwA=', // candidatePubkey
  '1.2.3.4', // candidateIP,
  8670, // candidatePort,
  300000000000000000000 // 300 MTRG
);

// get script data for staking bound
const scriptDataBuffer = ScriptEngine.getBoundData(
  ScriptEngine.Option.OneWeekLock,
  '0x7567d83b7b8d80addcb281a71d54fc7b3364ffed', // holderAddr
  '0x7567d83b7b8d80addcb281a71d54fc7b3364ffed', // candidateAddr
  10000000000000000000 // 10 MTRG
);

const scriptData = '0x' + scriptDataBuffer.toString('hex');

Decode

const scriptData = ScriptEngine.decodeScriptData(
  Buffer.from(
    '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',
    'hex'
  )
);
if (scriptData.header.modId === ScriptEngine.ModuleID.Staking) {
  const body = ScriptEngine.decodeStakingBody(scriptData.payload);
  console.log('STAKING BODY: ', body);
}

Transaction

let clauses = [
  {
    to: '0x7567d83b7b8d80addcb281a71d54fc7b3364ffed',
    value: 10000,
    data: '0x',
  },
];

// calc intrinsic gas
let gas = Transaction.intrinsicGas(clauses);
console.log(gas);
// 21000

let body: Transaction.Body = {
  chainTag: 0x9a,
  blockRef: '0x0000000000000000',
  expiration: 32,
  clauses: clauses,
  gasPriceCoef: 128,
  gas: 21000,
  dependsOn: null,
  nonce: 12345678,
};

let tx = new Transaction(body);
let signingHash = cry.blake2b256(tx.encode());
tx.signature = cry.secp256k1.sign(signingHash /* your private key */);

let raw = tx.encode();
let decoded = Transaction.decode(raw);

Certificate

supports client side self-signed certificate

let cert: Certificate = {
    purpose: 'identification',
    payload: {
        type: 'text',
        content: 'fyi'
    },
    domain: 'localhost',
    timestamp: 1545035330,
    signer: <<<signer-address>>>
}

let jsonStr = Certificate.encode(cert)
let signature = secp256k1.sign(cry.blake2b256(jsonStr), <<<private-key>>>)

cert.signature = '0x' + signature.toString('hex')

Certificate.verify(cert)

// certificate id
let id = '0x' + cry.blake2b256(Certificate.encode(cert)).toString('hex')

ABI

let fn = new abi.Function({
  constant: false,
  inputs: [
    {
      name: 'a1',
      type: 'uint256',
    },
    {
      name: 'a2',
      type: 'string',
    },
  ],
  name: 'f1',
  outputs: [
    {
      name: 'r1',
      type: 'address',
    },
    {
      name: 'r2',
      type: 'bytes',
    },
  ],
  payable: false,
  stateMutability: 'nonpayable',
  type: 'function',
});

let data = fn.encode(1, 'foo');