Web3js – How to Send Payment from Wallet on Ubuntu

When watching for events from web3, this is the format of the result you get when one is called:

{ address: '0x9c0ac1e0f0a8e0b01c7b652d5fbe094ddff48b81',
  blockNumber: 704227,
  transactionHash: '0x5887ba4e15d51e1cfddf626ecf416a0002085a1e0929fffe1f90ad69d5040081',
  transactionIndex: 0,
  blockHash: '0x5f485133ec662f556d88affccc18a358375de160178c6cf7cc0cec678d833a2a',
  logIndex: 0,
  removed: false,
  event: 'ExampleEvent',
  args: 
   { argOne: BigNumber { s: 1, e: 0, c: [Array] },
     argTwo: '0x374623456fa2' } }

So you can just get the TX from result.transactionHash

Event in contract:

event ExampleEvent(uint argOne, bytes32 argTwo)

Web3 code:

import exampleContractObject from 'path/to/ExampleContract.json'

ExampleContract = web3.eth.contract(exampleContractObject.abi);
contractInstance = ExampleContract.at('0x9c0ac1e0f0a8e0b01c7b652d5fbe094ddff48b81');
exampleEvent = contractInstance.ExampleEvent();

exampleEvent.watch((err, result) => {
  // Do something 
}

EDIT:

The Transfer event from ERC20 tokens would look like this:

{ address: '<contract_address>',
  blockNumber: <block_number>,
  transactionHash: '<transaction_hash>',
  transactionIndex: <tx_index_in_block,
  blockHash: '<block_hash>',
  logIndex: <log_index>,
  removed: <> ,
  event: 'Transfer',
  args: 
   { _from: <address>,
     _two: <address> ,
     _value: <uint256>} }

I've used this scripts to deploy a contract using web3 v1.0-beta24

const Web3 = require('web3');
const web3 = new Web3('http://127.0.0.1:8545');

const ownerAddress = "0x....";
const contractAbi = [{"constant":false.... }];
const contractCode = "0x606060...";

const MyContract = new web3.eth.Contract(contractAbi);

MyContract.deploy({
  data: contractCode,
})
.send({
  from: ownerAddress,
  gas: 4000000,
  gasPrice: '30000000000000',
})
.then((instance) => {
  console.log(`Address: ${instance.options.address}`);
});

And this other script to send a message and make a query

const Web3 = require('web3');
const web3 = new Web3('http://127.0.0.1:8545');

const ownerAddress = "0x....";
const contractAbi = [{"constant":false.... }];
const contractCode = "0x606060...";
const contractAddress = "0x....";  // <----- previous script output

const myContract = new web3.eth.Contract(contractAbi, contractAddress);

const options = {
  from: ownerAddress,
  gas: 4000000,
  gasPrice: '30000000000000',
};

const message = web3.utils.asciiToHex('hola');

myContract.methods.sendMessage(message)
.send(options, (err, hash) => {
  if (err) {
    console.log(err);
  }
  console.log(`TxHash: ${hash}`);
})
.then((result) => {
  myContract.methods.getMessage().call()
  .then((result) => {
    console.log(web3.utils.hexToAscii(result));
  });
});

The sample contract I've used is very simple

pragma solidity ^0.4.18;

contract Echo {
    bytes32 public message;

    function sendMessage(bytes32 _message) public {
        message = _message;
    }

    function getMessage() view public returns (bytes32) {
        return message;
    }
}