Information lost when getting string from byte32 Solidiy smart contract

Question

I have a number as a string which I pass to smart contract function as a parameter. The function takes byte32 as a parameter.

Here is the node.js code for executing the contract function:

const app = require("express")();
const config = require("./config");
const Web3 = require("web3");
const web3EndPoint = config.web3EndPoint;
const web3 = new Web3(new Web3.providers.HttpProvider(web3EndPoint));
const ethTx = require('./eth-transaction');
const abi = config.abi;
const MyContract = web3.eth.contract(abi);
const myContractInstance = MyContract.at(config.contractAddress);

txnCount = web3.eth.getTransactionCount(config.defaultAccount);

const parameter = '1234';
const data = myContractInstance.setID.getData(parameter);
myContractInstance.setID.estimateGas(parameter, (error , value) => {
    if (!error) {
        console.log("gasLimit" , value);
        const rawTx = {
            nonce: web3.toHex(txnCount) ,
            gasPrice: web3.toHex(100000000000) ,
            gasLimit: value ,
            to: config.contractAddress ,
            value: web3.toHex(0) ,
            data: data ,
        };

        ethTx.sendRawTransaction(config.priKey , rawTx , web3 ).then((result) => {
            console.log(result);
        }).catch(transactionFailedErr => {
            console.error(transactionFailedErr);
        });
    } else {
        console.error(error);
    }
});

myContractInstance.LogTestCase().watch((error, result) => {
    console.log(web3.toUtf8(result.args._id)); // Its logs 'M'
});

Here is the solidity code:

pragma solidity ^0.4.21;

contract test2 {

    bytes32 public _id;

    event LogTestCase(
        bytes32 _id
    );

    function setID(bytes32 cId) returns (bool){
        _id = cId;
        emit LogTestCase(_id);
        return true;
    }
}

Now when I put '1234' as a parameter, fetching it from the contract event results in 'M'. But when I put any other string containing alphabets, I get the correct initial string

So passing any number as a string to the contract function with byte32 type cannot be retrieved. Is there any way to get exactly what I passed?

Answer 1

In order to pass byte32 parameter properly you need to use 0x prefix in value (e.g. '0x1234')

or take a look how to convert string to bytes32 https://ethereum.stackexchange.com/a/23110/30889