4

I followed the following tutorial: https://medium.com/@mvmurthy/full-stack-hello-world-voting-ethereum-dapp-tutorial-part-1-40d2d0d807c2

Now this tutorial is not using the recent version of web3 but I tried to solve this with the web3 documentation.

This is how far I got:

>byteCode = compiledCode.contracts[':Voting'].bytecode       
>deployedContract = VotingContract.new(['Rama','Nick','Jose'],{data:   byteCode, from: web3.eth.accounts[0], gas: 4700000})
>deployedContract.address
>contractInstance = VotingContract.at(deployedContract.address)

I successfully compiled the byteCode and deployed the contract in the following way:

> VotingContract.deploy({ data: byteCode, arguments: [[web3.utils.asciiToHex("name1"),web3.utils.asciiToHex("name2"),web3.utils.asciiToHex("name3")]] }).send({ from: acc1, gas: 4700000, gasPrice: '3000000' }).on('confirmation', function(confirmationNumber, receipt){console.log(confirmationNumber + ' ' + receipt) }).then(function(instance) {contractInstance = instance});

Now I should have a contract instance, shouldn't I? Or is this something else? The author goes on to do the following:

>contractInstance = VotingContract.at(deployedContract.address)

I did this instead:

var contract3 = new web3.eth.Contract(byteCode, contractInstance.options.address, {from: acc1, gasPrice:'3000000'});

Now if I try to call methods on this contract like:

contract3.methods.totalVotesFor(web3.utils.toHex('name1')).call(acc1).then(function(returned, err) {console.log(returned + ' ' + err)});

I receive the following response:

Promise {
  _bitField: 0,
  _fulfillmentHandler0: undefined,
  _rejectionHandler0: undefined,
  _promise0: undefined,
  _receiver0: undefined }
> Unhandled rejection Error: Returned error: Error: VM Exception while executing eth_call: invalid opcode
    at C:\Path\node_modules\ethereumjs-testrpc\build\cli.node.js:59368:17
    at C:\Path\node_modules\ethereumjs-testrpc\build\cli.node.js:69306:5
    at C:\Path\node_modules\ethereumjs-testrpc\build\cli.node.js:11335:9
    at C:\Path\node_modules\ethereumjs-testrpc\build\cli.node.js:7895:16
    at replenish (C:\Path\node_modules\ethereumjs-testrpc\build\cli.node.js:8415:25)
    at iterateeCallback (C:\Path\node_modules\ethereumjs-testrpc\build\cli.node.js:8405:17)
    at C:\Path\node_modules\ethereumjs-testrpc\build\cli.node.js:8380:16
    at C:\Path\node_modules\ethereumjs-testrpc\build\cli.node.js:11332:13
    at C:\Path\node_modules\ethereumjs-testrpc\build\cli.node.js:69302:9
    at C:\Path\node_modules\ethereumjs-testrpc\build\cli.node.js:63982:7
    at Object.ErrorResponse (C:\Path\node_modules\web3-core-helpers\src\errors.js:29:16)
    at C:\Path\node_modules\web3-core-requestmanager\src\index.js:137:36
    at XMLHttpRequest.request.onreadystatechange (C:\Path\node_modules\web3-providers-http\src\index.js:64:13)
    at XMLHttpRequestEventTarget.dispatchEvent (C:\Path\node_modules\xhr2\lib\xhr2.js:64:18)
    at XMLHttpRequest._setReadyState (C:\Path\node_modules\xhr2\lib\xhr2.js:354:12)

What might I be doing wrong?

Thanks for your help!

  • Please check this question. It might help. – 1sn0s Jan 7 '18 at 11:17
  • Based on the answer below, I think the issue might be in the contract code. Could you please share that – 1sn0s Feb 12 '18 at 4:00
0

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;
    }
}
  • That didnt work for me, Infact I was getting empty methods{}, because of which web3js throws me error cannot get length of undefined. I am using beta 10 – siva Feb 15 '18 at 4:23
  • @siva I was using beta24 when the test was done, you should try with a more recent build. When time permits I'll check if the example is working with latest build. – Ismael Feb 15 '18 at 5:23
0

The contract address is returned on receipt or confirmation event. Here is complete code that votes and get result.

const fs = require('fs');
const solc = require('solc');
const Web3 = require('web3');
const web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:7545"));

async function deploy() {
    let accounts = await web3.eth.getAccounts();

    let code = fs.readFileSync('Voting.sol').toString();
    let compiledCode = solc.compile(code);
    let abi = JSON.parse(compiledCode.contracts[':Voting'].interface);
    let bytecode = compiledCode.contracts[':Voting'].bytecode;
    let votingContract = new web3.eth.Contract(abi, {from: accounts[0], gas: 47000, data: bytecode});

    let rama = web3.utils.asciiToHex('Rama');
    let nick = web3.utils.asciiToHex('Nick');
    let jose = web3.utils.asciiToHex('Jose');

    let contractInstance = await votingContract.deploy({
        arguments: [[rama, nick, jose]]
    })
    .send({
        from: accounts[0],
        gas: 1500000
    }, (err, txHash) => {
        console.log('send:', err, txHash);
    })
    .on('error', (err) => {
        console.log('error:', err);
    })
    .on('transactionHash', (err) => {
        console.log('transactionHash:', err);
    })
    .on('receipt', (receipt) => {
        console.log('receipt:', receipt);
        votingContract.options.address = receipt.contractAddress;
    });

    console.log('contractInstance.options:', contractInstance.options);

    let result = await votingContract.methods.totalVotesFor(rama).call({from: accounts[0]});
    console.log('result:', result); // 0

    let receipt = await votingContract.methods.voteForCandidate(rama).send({from: accounts[0]});
    console.log('voteForCandidate receipt:', receipt);

    result = await votingContract.methods.totalVotesFor(rama).call({from: accounts[0]});
    console.log('new result:', result); // 1
}

deploy()
.then(() => console.log('Success'))
.catch(err => console.log('Script failed:', err));
0

I had a similar problems. I think there is a bug in web3.0 when it comes to constructor-arguments. The constructor-values must be added as hex at the end of the bytecode, when you create the tx to deploy the contract.

You can use eth-crypto's txDataByCompiled and then submit the transaction manually.

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