gwei-alert-bot/src/blockchain.ts

import 'dotenv/config.js';
import Web3 from 'web3';

import { GasPrices } from '../types/gasPrices'
import redisClient from './redis';

const rpcUrl = process.env.RPC_URL || 'ws://localhost:8545';

// Create a new web3 instance
const web3 = new Web3(new Web3.providers.WebsocketProvider(rpcUrl, {
  reconnect: {
    auto: true,
    delay: 5000,
    maxAttempts: 5,
    onTimeout: false
  }
}));

export const subToBlockHeaders = (setDiscordStatus: () => Promise<void>) => {
  web3.eth.subscribe('newBlockHeaders', (error, blockHeader) => {
    if (error) console.error(error);
    
    const shouldLogWei = blockHeader.number % 10 === 0;
    
    // Get the gas price for this block
    web3.eth.getGasPrice((error, gasPrice) => {
      if (error) console.error(error);
      
      if (shouldLogWei) console.log('Gas price in wei:', gasPrice);
      
      redisClient.set('gas-price', Math.round(Number(gasPrice)))
    });
    
    // Set status every block
    setDiscordStatus()
  });
}

const gweiFromWei = (priceInWei: number): number =>
  Math.round(Number(web3.utils.fromWei(`${Math.round(priceInWei)}`, 'gwei')));

const getGasPrice = async (): Promise<number> => {
  const gasPrice = await redisClient.get('gas-price');
  return Number(gasPrice);
}

const getGasPricesInGwei = async (): Promise<GasPrices> => {
  const gasPrice = await getGasPrice()
  const fastPrice = gasPrice * 1.1;
  const slowPrice = gasPrice * 0.9;
  
  const gasPrices = {
    fast: gweiFromWei(fastPrice),
    average: gweiFromWei(gasPrice),
    slow: gweiFromWei(slowPrice),
  };

  return gasPrices;
};

export { getGasPricesInGwei };