Search for a command to run...
Alfred is a software engineer and cyber security specialist based in Enugu, Nigeria. He is passionate about solving real-world problems through well-crafted software and leveraging blockchain technology.
No comments yet. Be the first to comment.
The tech industry is changing fast—but not in the way most people think. By 2026, success in engineering won’t be about chasing the newest tools or stacking buzzwords on a résumé. It will be about depth, ownership, and usefulness. Here’s a grounded l...
1. Server Streaming RPC: Description: In this type of RPC, the client sends a single request to the server, and the server responds with a stream of messages. The client reads from this stream of responses until there are no more messages. Use Case...
Email communication is a crucial aspect of many applications, and Amazon Simple Email Service (SES) provides a reliable and scalable solution for sending emails in the Amazon Web Services (AWS) environment. I've created a go package that facilitates ...
Introduction This article shows a complete setup on how you can verify a signature sent by paystack when they make a POST request to your server. I'm using the bun http router as my go lang framework. I really do not have strength for long talks, so ...
Funny title, but that's the reality from January to December. So, you're here to hear some gist about my 2023, say less. First I just want to take a moment to laugh small, 😂😂😂😂 why? the plans I had for 2023 come be like say na small pikin write a...
Below are code snippets that work for creating wallet addresses, checking wallet balances, and sending ether to another wallet. My provider is infura, get your free account already.
npm package versions
"web3": "^1.3.6", "ethereumjs-tx": "^2.1.2"
Below is an extraction of my code that works which I use in building my Dapp, basically I am managing the user's wallet credentials.
const wssethProvider =
"wss://rinkeby.infura.io/ws/v3/YOUR-API-KEY";
exports.createETHAddress = async (req, res, next) => {
try {
const { email, userId } = req.body;
const web3 = new Web3(new Web3.providers.WebsocketProvider(wssethProvider));
web3.setProvider(new Web3.providers.WebsocketProvider(wssethProvider));
const account = web3.eth.accounts.wallet.create(1, `${email}${userId}`);
const accountKeyStore = web3.eth.accounts.encrypt(
account[0].privateKey,
`SMART__07b7ee54020142cb8d7b2a6c963a0b4e`
);
res.json({
status: "ok",
account: account[0],
accountKeyStore,
});
} catch (e) {
next(User.checkDuplicateEmail(e));
}
exports.getETHBalance = async (req, res, next) => {
try {
const { address } = req.params;
const web3 = new Web3(
new Web3.providers.WebsocketProvider(wssethProvider)
);
web3.setProvider(new Web3.providers.WebsocketProvider(wssethProvider));
let balance = await web3.eth.getBalance(address);
balance = web3.utils.fromWei(balance, "ether");
res.json({
status: "ok",
balance: String(balance)
});
} catch (e) {
next(User.checkDuplicateEmail(e));
}
};
Using ethereumjs-tx to sing transactions, and web3 to broadcast the transaction to the network for verification and processing.
exports.transferEth = async (req, res, next) => {
try {
const web3 = new Web3(new Web3.providers.WebsocketProvider(wssethProvider));
web3.setProvider(new Web3.providers.WebsocketProvider(wssethProvider));
web3.eth.defaultAccount = req.body.from;
const {
amount, to, sendersPrivateKey, from
} = req.body;
const privateKey = await Buffer.from(sendersPrivateKey.substr(2), 'hex');
const myBalanceWei = await web3.eth.getBalance(web3.eth.defaultAccount);
const myBalance = web3.utils.fromWei(myBalanceWei, 'ether');
console.log(`Your wallet balance is currently ${myBalance}`);
const nonce = await web3.eth.getTransactionCount(web3.eth.defaultAccount);
console.log(`The outgoing transaction count for your wallet address is: ${nonce}`);
const gasPrices = await getCurrentGasPrices();
console.log(`The current gas price is ${gasPrices.low} ETH/GAS`);
const details = {
from,
to,
value: web3.utils.toHex(web3.utils.toWei(amount, 'ether')),
gasLimit: 21000,
gasPrice: gasPrices.low * 1000000000, // converts the gwei price to wei
nonce,
chainId: 4 // EIP 155 chainId - mainnet: 1, rinkeby: 4
};
const transaction = new EthereumTx.Transaction(details, { chain: 'rinkeby' });
await transaction.sign(privateKey);
const serializedTransaction = await transaction.serialize();
const sd = String(`0x${serializedTransaction.toString('hex')}`);
const transactionId = await web3.eth.sendSignedTransaction(sd);
return res.send(transactionId);
} catch (error) {
return res.send('Failed to send transaction');
}
};
Note that, all transactions are recorded on the rinkeby testnet, do well to switch to the main net url provided by infura which can be found on your dashboard.
Resources Used
Feel free to ask me questions about this code in the comments, cheers!!😊