The send transactions "from" field must be defined using Infura web3

Question

when I try to send my transaction using infura I get this error

      "The send transactions "from" field must be defined" 

My problem is my web3 object. When I used Metamask and my app from a Google Chrome page I did't have problem

  App.web3Provider = web3.currentProvider
  web3 = new Web3(web3.currentProvider)

Now, using Truffle, I need to interact with my smart contract without metamask.

I get my web3 from infura.

    App.web3Provider = new Web3.providers.HttpProvider("https://ropsten.infura.io/v3/2a8xxxxxxxxxxxxxxx")
    web3 = new Web3(App.web3Provider)

(UPDATE) Iteraction with my Smart Contract

    const partecipazioneContest = await $.getJSON('File.json')
    App.contracts.PartecipazioneContest = TruffleContract(partecipazioneContest)
    App.contracts.PartecipazioneContest.setProvider(App.web3Provider)
    App.partecipazioneContest = await App.contracts.PartecipazioneContest.deployed()

Error when I make the transaction:

  await App.partecipazioneContest.addUser(parameters);

I think my problem is that it does't load my account, so I create my account from my private key and i get the correct addres, but when I try to get my account with getAccount() function the accounts are empty.

    await web3.eth.accounts.privateKeyToAccount('0x33434XXXXXXXXXXX13');
    web3.eth.getAccounts().then(function(acc){ 
      accounts = acc 
      console.log(accounts)
      alert(" getAccounts " + accounts)

    })

How to load my web3 returned from infura with my accounts and all the information that i need to interact with the smart contracts?
I would like to interact with my Smart contract with my wallet on Metamask passing by infura

Answer 1

You can use wrap Web3.js provider with a Truffle HDWalletProvider.

HDWalletProvider wraps the underlying provider and allows you easily use send() with ETH and smart contract transactions with the existing web3.js and contract APIs.

• Wrap web3 provider with HDWalletProvider
• Import your private keys to HDWalletProvider
• Interact with smart contracts and such, set send({from: ...}) to an account that maches the imported private keys