Web3py Infura – Fix ‘eth_newFilter Does Not Exist’ Error When Getting Events

infuraweb3.py

I'm trying to get all events from contract, but get error:
"ValueError: {'code': -32601, 'message': 'The method eth_newFilter does not exist/is not available'}"

I'm using Web3py and Infura. My code:

myfilter = <myContract>.events.<MyEvent>.createFilter(fromBlock=0)

myFilter = web3.eth.filter({"address": <myContractAddress>})

Why is this error? How do I get events?
Help me please.

Best Answer

The issue is that Infura only exposes the eth_newFilter endpoint via websockets, but you are connecting via https.

Try using a WebsocketProvider when declaring your web3 instance, as shown in the following example:

from web3 import Web3

PROVIDER = "wss://ropsten.infura.io/ws/v3/YOUR-PROJECT-ID"
web3 = Web3(Web3.WebsocketProvider(PROVIDER))

Related Solutions

Web3JS – How to Make Smart Contract Calls Using INFURA and NodeJS

First of all INFURA does not allows to send unsigned transactions, so you have to sign them firstly and then pass them to INFURA.

To do this, you have to:

prepare the transaction
sign it
send it (using INFURA)

Please check INFURA documentation.

There is an example below:

const Web3 = require('web3')
const Tx = require('ethereumjs-tx')

// connect to Infura node
const web3 = new Web3(new Web3.providers.HttpProvider('https://mainnet.infura.io/INFURA_KEY'))

// the address that will send the test transaction
const addressFrom = '0x1889EF49cDBaad420EB4D6f04066CA4093088Bbd'
const privKey = 'PRIVATE_KEY'

// the destination address
const addressTo = '0x1463500476a3ADDa33ef1dF530063fE126203186'

// Signs the given transaction data and sends it. Abstracts some of the details 
// of buffering and serializing the transaction for web3.
function sendSigned(txData, cb) {
  const privateKey = new Buffer(config.privKey, 'hex')
  const transaction = new Tx(txData)
  transaction.sign(privateKey)
  const serializedTx = transaction.serialize().toString('hex')
  web3.eth.sendSignedTransaction('0x' + serializedTx, cb)
}

// get the number of transactions sent so far so we can create a fresh nonce
web3.eth.getTransactionCount(addressFrom).then(txCount => {

  // construct the transaction data
  const txData = {
    nonce: web3.utils.toHex(txCount),
    gasLimit: web3.utils.toHex(25000),
    gasPrice: web3.utils.toHex(10e9), // 10 Gwei
    to: addressTo,
    from: addressFrom,
    value: web3.utils.toHex(web3.utils.toWei(123, 'wei'))
  }

  // fire away!
  sendSigned(txData, function(err, result) {
    if (err) return console.log('error', err)
    console.log('sent', result)
  })

})

Web3.py – Making an ERC20 Transfer Using Python

transact() asks the node to sign your transaction using eth_sendTransaction. Infura can't do that, because they don't have your keys.

Instead, you can use the contract object to create an unsigned transaction like:

contract_call = contract.functions.transfer(destination_address, value)
unsigned_txn = contract_call.buildTransaction({'chainId': 1, 'gasPrice': w3.toWei(100, 'gwei')})

Then you can sign the transaction with your private key, and broadcast it:

signed_txn = w3.eth.account.sign_transaction(unsigned_txn, private_key=private_key)
w3.eth.sendRawTransaction(signed_txn.rawTransaction)

Best Answer

Related Solutions

Web3JS – How to Make Smart Contract Calls Using INFURA and NodeJS

Web3.py – Making an ERC20 Transfer Using Python

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