import * as _ from 'lodash'; import * as timers from 'timers'; // HACK: web3 leaks XMLHttpRequest into the global scope and causes requests to hang // because they are using the wrong XHR package. // Filed issue: https://github.com/ethereum/web3.js/issues/844 // tslint:disable-next-line:ordered-imports import * as Web3 from 'web3'; const MAX_QUEUE_SIZE = 500; const DEFAULT_QUEUE_INTERVAL_MS = 1000; export class RequestQueue { protected queueIntervalMs: number; protected queue: string[]; protected queueIntervalId: NodeJS.Timer; protected web3: Web3; constructor(web3: any) { this.queueIntervalMs = DEFAULT_QUEUE_INTERVAL_MS; this.queue = []; this.web3 = web3; this.start(); } public add(recipientAddress: string): boolean { if (this.isFull()) { return false; } this.queue.push(recipientAddress); return true; } public size(): number { return this.queue.length; } public isFull(): boolean { return this.size() >= MAX_QUEUE_SIZE; } protected start() { this.queueIntervalId = timers.setInterval(() => { const recipientAddress = this.queue.shift(); if (_.isUndefined(recipientAddress)) { return; } // tslint:disable-next-line:no-floating-promises this.processNextRequestFireAndForgetAsync(recipientAddress); }, this.queueIntervalMs); } protected stop() { clearInterval(this.queueIntervalId); } // tslint:disable-next-line:prefer-function-over-method protected async processNextRequestFireAndForgetAsync(recipientAddress: string) { throw new Error('Expected processNextRequestFireAndForgetAsync to be implemented by a superclass'); } }