const { ethers } = require('ethers') const { fetchJson } = require('@ethersproject/web') const { numbers } = require('./constants') const defaultRetryAttempt = 0 class ExtendedProvider extends ethers.providers.StaticJsonRpcProvider { constructor(url, network, fallbackRpcs) { super(url, network) this.fallbackRpcs = fallbackRpcs } async send(method, params, retryAttempt = defaultRetryAttempt) { try { return await super.send(method, params) } catch (err) { if (!retryAttempt) { const TIME_OUT = 3000 await this.sleep(TIME_OUT) if (this.fallbackRpcs) { return await this.fallbackSend(method, params, this.fallbackRpcs) } return this.send(method, params, ++retryAttempt) } throw err } } // eslint-disable-next-line async fallbackSend(method, params, fallbackRpcs, retryAttempt = defaultRetryAttempt) { function getResult(payload) { if (payload.error) { const error = new Error(payload.error.message) error.code = payload.error.code error.data = payload.error.data // eslint-disable-next-line @typescript-eslint/no-throw-literal throw error } return payload.result } try { const request = { method: method, params: params, id: this._nextId + numbers.ONE, jsonrpc: '2.0', } const result = fetchJson({ url: fallbackRpcs[retryAttempt] }, JSON.stringify(request), getResult).then( (result) => result, (error) => { throw error }, ) return await result } catch (err) { retryAttempt += numbers.ONE if (!fallbackRpcs[retryAttempt]) { throw err } else { return await this.fallbackSend(method, params, fallbackRpcs, retryAttempt) } } } async sleep(ms) { return await new Promise((resolve) => setTimeout(resolve, ms)) } // private checkRpcError(err: { data: string; code: string; message: string }) { // const code = String(err?.code) // const data = err.data?.toLowerCase() // const message = err.message?.toLowerCase() // const ERROR_DATA = 'too many concurrent request' // const ERROR_MESSAGE = 'timeout' // const ERROR_CODE = '-32017' // return (data?.includes(ERROR_DATA) || message?.includes(ERROR_MESSAGE)) && code === ERROR_CODE // } } module.exports = { ExtendedProvider }