JavaScript code to deploy a contract (authentication)

Question

When I run my contract deploy code in a browser (even if MetaMask is installed), I get this error:

authentication needed: password or unlock

The code follows:

var owner = $('#account').val();
var contract = web3.eth.contract(abi);
var contractInstance = contract.new(
    tokenName, tokenSymbol, { data: bytecode, from: owner, gas: 6721975 }
);

Please, please, explain how to do authentication for the user to be able to deploy my contract.

web3.js 0.20.6.

---

I connect to network with the following code:

    var provider = new Web3.providers.HttpProvider('http://localhost:8545');
    var web3 = new Web3(provider);

Answer 1

To use MetaMask, you need code that looks like this:

var web3 = new Web3(web3.currentProvider);

(MetaMask injects a web3 global variable that has the right provider attached.)

To have MetaMask connect to your local geth node, just click the drop-down in the MetaMask UI that lets you choose your network. One of the options should be "localhost 8545." If you're not on that port, you can choose "custom RPC" and specify a URL.

Answer 2

You can also set it up like so:

const assert = require('assert');
const ganache = require('ganache-cli');
const Web3 = require('web3');

const provider = ganache.provider();
const web3 = new Web3(provider);

const { interface, bytecode } = require('../compile');

let accounts;
let inbox;

beforeEach(async () => {
  // Get a list of accounts
  accounts = await web3.eth.getAccounts();

  // Use one of those accounts to deploy contract
  inbox = await new web3.eth.Contract(JSON.parse(interface))
    .deploy({
      data: bytecode,
      arguments: ['hi there']
    })
    .send({ from: accounts[0], gas: '1000000' });

  inbox.setProvider(provider);
});