Error: The method eth_sendTransaction does not exist/is not available

Question

Showing an error while calling solidity contract, which is deployed already in ropsten-infura. I'm using web3(@0.19.1) for calling contract.

Anybody faced the same issue?

Solution 1

I'm guessing that you're connected directly to Infura, which doesn't support eth_sendTransaction. (For it to support that, it would need to know your private key, but it's a shared public node.)

You need to either sign the transaction yourself and then send via eth_sendRawTransaction or use a provider that can hold private keys like MetaMask in the browser.

Solution 2

this is a sample of smart contract function execution: as we know it's not possible to make a transaction in Ethereum network without fee, so you can delegate the fee payment by the contact account

                                    const rawTx =
                                    {
                                        nonce: _hex_nonce,
                                        from: MainAccountAddress,
                                        to: contractAddress,
                                        gasPrice: _hex_gasPrice,
                                        gasLimit: _hex_gasLimit,
                                        gas: _hex_Gas,
                                        value: '0x0',
                                        data: contract.methods.transfer(toAddress, _hex_value).encodeABI()
                                    };

                                    const tx = new Tx(rawTx, { 'chain': 'ropsten' });
                                    tx.sign(privateKey);

                                    var serializedTx = '0x' + tx.serialize().toString('hex');
                                    web3.eth.sendSignedTransaction(serializedTx.toString('hex'), function (err, hash) {
                                        if (err) {
                                            reject(err);
                                        }
                                        else {
                                            resolve(hash);
                                        }
                                    })

here is the full source to execute the smart contract with delegation by contract main accout:

async function TransferERC20Token(toAddress, value) {
return new Promise(function (resolve, reject) {
    try {
        web3.eth.getBlock("latest", false, (error, result) => {
            var _gasLimit = result.gasLimit;
            let contract = new web3.eth.Contract(contractABI, contractAddress);

            contract.methods.decimals().call().then(function (result) {
                try {
                    var decimals = result;
                    let amount = parseFloat(value) * Math.pow(10, decimals);
                    web3.eth.getGasPrice(function (error, result) {
                        var _gasPrice = result;
                        try {
                            const Tx = require('ethereumjs-tx').Transaction;
                            const privateKey = Buffer.from(MainAccountPrivateKey, 'hex')

                            var _hex_gasLimit = web3.utils.toHex((_gasLimit + 1000000).toString());
                            var _hex_gasPrice = web3.utils.toHex(_gasPrice.toString());
                            var _hex_value = web3.utils.toHex(amount.toString());
                            var _hex_Gas = web3.utils.toHex('60000');

                            web3.eth.getTransactionCount(MainAccountAddress).then(
                                nonce => {
                                    var _hex_nonce = web3.utils.toHex(nonce); 

                                    const rawTx =
                                    {
                                        nonce: _hex_nonce,
                                        from: MainAccountAddress,
                                        to: contractAddress,
                                        gasPrice: _hex_gasPrice,
                                        gasLimit: _hex_gasLimit,
                                        gas: _hex_Gas,
                                        value: '0x0',
                                        data: contract.methods.transfer(toAddress, _hex_value).encodeABI()
                                    };

                                    const tx = new Tx(rawTx, { 'chain': 'ropsten' });
                                    tx.sign(privateKey);

                                    var serializedTx = '0x' + tx.serialize().toString('hex');
                                    web3.eth.sendSignedTransaction(serializedTx.toString('hex'), function (err, hash) {
                                        if (err) {
                                            reject(err);
                                        }
                                        else {
                                            resolve(hash);
                                        }
                                    })
                                });                                
                        } catch (error) {
                            reject(error);
                        }
                    });
                } catch (error) {
                    reject(error);
                }
            });
        });
    } catch (error) {
        reject(error);
    }
})

}