how to write backend for contract if you use infura ropsten metamask and remix

Question

i'm using metamask with ropsten. deployed my contract on ropsten using remix. for the backend i used infura to create instance of web3. ew Web3(new Web3.providers.HttpProvider('https://ropsten.infura.io/v3/MY_API_KEY'));

i'm able to get data from blockchain by contract.getDetails(123); but while sending the details i'm getting below error, "The method eth_sendTransaction does not exist/is not available"

Answer 1

I understand you problem, this is due to API version change between Infura and Web3. Please try to match the version of Web3 API with Infura.

Answer 2

Install and use truffle-hdwallet-provider to create a provider using your mnemonic and the infura endpoint. You can then pass this provider while creating instance of Web3:

const HDWalletProvider = require("truffle-hdwallet-provider");

const provider = new HDWalletProvider(
  mnemonic,
  'https://ropsten.infura.io/v3/MY_API_KEY'
);

const web3 = new Web3(provider);