How to authenticate and send contract method using web3.js 1.0

Question

I am confused about how I should be executing a contract\'s method using the web3 1.0 library.

This code works (so long as I manually unlock the account first):

Answer 1

Here's a complete example of how to sign a transaction without a local wallet account. Especially useful if you are using infura for the transaction. This was written for

'use strict';
const Web3 = require('web3');

const wsAddress = 'wss://rinkeby.infura.io/ws';
const contractJson = '(taken from solc or remix online compiler)';
const privateKey = '0xOOOX';
const contractAddress = '0xOOOX';
const walletAddress = '0xOOOX';

const webSocketProvider = new Web3.providers.WebsocketProvider(wsAddress);
const web3 = new Web3(new Web3.providers.WebsocketProvider(webSocketProvider));
const contract = new web3.eth.Contract(
  JSON.parse(contractJson),
  contractAddress
);
// change this to whatever contract method you are trying to call, E.G. SimpleStore("Hello World")
const query = contract.methods.SimpleStore('Hello World');
const encodedABI = query.encodeABI();
const tx = {
  from: walletAddress,
  to: contractAddress,
  gas: 2000000,
  data: encodedABI,
};

const account = web3.eth.accounts.privateKeyToAccount(privateKey);
console.log(account);
web3.eth.getBalance(walletAddress).then(console.log);

web3.eth.accounts.signTransaction(tx, privateKey).then(signed => {
  const tran = web3.eth
    .sendSignedTransaction(signed.rawTransaction)
    .on('confirmation', (confirmationNumber, receipt) => {
      console.log('=> confirmation: ' + confirmationNumber);
    })
    .on('transactionHash', hash => {
      console.log('=> hash');
      console.log(hash);
    })
    .on('receipt', receipt => {
      console.log('=> reciept');
      console.log(receipt);
    })
    .on('error', console.error);
});

Using

"web3": "1.0.0-beta.30"