[WIP] Reku: Reliable ETH Kit & Utils

Event Cross-Check

• used for cross-checking missing events using eth getLogs
• note: cross-check interval shouldn't < 5min, otherwise rpc call would be expensive. Recommend set to 1 hour + 50 blocks (for redundancy check).

BaseCrossChecker

• onMissingLog: FnOnMissingLog: the callback function that will be called when there's a missing log found;
• ignoreLogs?: SimpleLog[] : it allows users to pass in the txhash list (,log index list) that already processed, let the crosschecker to ignore them.

crossCheckRange

crossCheckRetro

crossCheckFrom

AutoCrossCheck

Conceptually it supports 'catchup', 'realtime', 'mix' modes, controled by fromBlock and toBlock;

• realtime mode: run over the latest block data; enter when fromBlock and toBlock are NOT present; starts from latestblocknum+1 and never ends, always waits until latestblocknum >= lastcheckpoint + batchBlocksCount;
• catchup mode: run over historical block data; enter when fromBlock and toBlock is present; starts from fromBlock and ends at toBlock;
• mix mode: start in catchup mode and transit to realtime mode; enter when fromBlock is present and toBlock is NOT; auto-transit when lastcheckpoint > latestblocknum - batchBlocksCount;

i.e. It starts with 'realtime' mode by default.

Options:

• store?: the Store used to cache the <txhash, logindex> that already processed.
• storeKeyPrefix?: set the prefix to all keys when set key-value to store (cache), e.g. key = prefix+'txHashList', prefix can be "project:app:network:" to form a "project:app:network:txHashList" redis key., defult: ''
• storeTtl?: the ttl for <txhash, logindex> record in store, defualt: no limit
• batchBlocksCount?: how many blocks to get per getLogs check, in readtime mode it waits until the new block num >= batchBlocksCount. default: 10
• delayBlockFromLatest?: mostly for realtime mode; each time cc wait until latest height > toBlock + delayBlockFromLatest, default: 1
• blockInterval?: the block interval (in ms) of the given chain, default: 12000 for eth
• pollingInterval?: how long does it take between 2 block height check polling checks; mostly for limiting getLogs calling rate in catchup mode, default: 3000 ms
• fromBlock?: once specified, it means start catching up from historical blocks
• toBlock?: once specified, it means the crosscheck isn't infinite and will end at this height; need fromBlock present if this set

Usage

const acc = new AutoCrossChecker(provider)
await acc.start({
  onMissingLog,
  ignoreLogs,
  fromBlock: 20003371, // optional, empty to start from latest
  toBlock: 20003371, // optional, empty to enter continueous cc
  address: CONTRACT_ADDRESS,
  topics,
  batchBlocksCount: 1,
  pollingInterval: 3000,
})

Provider Manager

RekuProviderManager is a TypeScript class designed to manage Ethereum providers and contracts. It supports both WebSocket and JSON-RPC providers, includes heartbeat functionality to maintain the connection, and provides event listening and management features.

Usage

Import and Initialization

First, import the RekuProviderManager class:

import { RekuProviderManager } from '@ora-io/reku'

Then, create an instance of RekuProviderManager:

const providerManager = new RekuProviderManager('wss://your-ethereum-node-url', {
  heartbeatInterval: 5000, // Optional, default is 10 seconds
  disabledHeartbeat: false // Optional, whether to disable heartbeat
})

Adding Contracts

You can add a contract using its address and ABI:

const contractAddress = '0xYourContractAddress'
const contractAbi = [] // Your contract ABI

providerManager.addContract(contractAddress, contractAbi)

Or add a contract using an ethers.Contract instance:

const contract = new ethers.Contract(contractAddress, contractAbi, providerManager.provider)
providerManager.addContract(contractAddress, contract)

Event Listening

Adding Event Listeners

providerManager.addListener(contractAddress, 'EventName', (event) => {
  console.log('Event received:', event)
})

Removing Event Listeners

providerManager.removeListener(contractAddress, 'EventName', listener)

Removing All Event Listeners

providerManager.removeAllListeners()

Event Management

You can listen for RekuProviderManager errors and close events:

providerManager.on('error', (error) => {
  console.error('Provider error:', error)
})

providerManager.on('close', (code, reason) => {
  console.log(`Provider closed: ${code} - ${reason}`)
})

Reconnecting

You can manually reconnect to the provider:

providerManager.reconnect()

Destroying

When you no longer need the RekuProviderManager, you can destroy it to free up resources:

providerManager.destroy()

Configuration Options

The RekuProviderManager constructor accepts an optional configuration object:

heartbeatInterval: Heartbeat interval time (in milliseconds), default is 10 seconds.
disabledHeartbeat: Whether to disable the heartbeat, default is false.

Contract Manager

The RekuContractManager class is designed to manage Ethereum smart contracts using the ethers library. It provides methods to add, remove, and manage event listeners for contract events.

Example Usage

import { ethers } from 'ethers'
import { RekuContractManager } from '@ora-io/reku'

const provider = new ethers.providers.WebSocketProvider('wss://your-ethereum-node-url')
const contractAddress = '0xYourContractAddress'
const contractAbi = [] // Your contract ABI

const manager = new RekuContractManager(contractAddress, contractAbi, provider)

// Adding an event listener
manager.addListener('EventName', (event) => {
  console.log('Event received:', event)
})

// Removing an event listener
manager.removeListener('EventName', listener)

// Removing all event listeners
manager.removeAllListeners()

// Retrying all event listeners
manager.retryAllListeners()

// Retrying a specific event listener
manager.retryListener('EventName')