NodeJS + Web3 + Infura Ropsten - Error: Invalid JSON RPC response: “”

Question

I have problem with invalid response to ethereum from BE NodeJS app. I got error like:

Error: Invalid JSON RPC response: ""

Below I'd attached my simple code for testing connection.

const Web3 = require("web3");
const web3 = new Web3(new Web3.providers.HttpProvider(providerUrl));
const contract_web3 = new web3.eth.Contract(abi, contractAddress);

console.log("Config Data: \n", providerUrl, "\n", config.privateKey, "\n", contractAddress);

contract_web3.methods.getDocuments().call((err, result) => {
    if (err) {
        // handle error here
        console.log("Test call error: ", err);
    }
    else {
        console.log("Test call: ", result);
    }
})

I'v readed about HDWalletProvider, but I havent dive in it yet.

Regards!

Answer 1

Ok. With this code the parts were errors might occur are very limited.

Make sure providerUrl has the correct value.

I hope you filled contractAddress correctly.

Abi is the bigger problem. Do a console.log of it. I would suggest a JSON.parse on the abi. This might fix the problem.

EDIT: What is your web3 version? Make sure not to use an outdated one.