/* * Copyright (C) 2019-2020 Alex Yatskov <alex@foosoft.net> * Author: Alex Yatskov <alex@foosoft.net> * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <https://www.gnu.org/licenses/>. */ class FrontendApiSender { constructor() { this.senderId = FrontendApiSender.generateId(16); this.ackTimeout = 3000; // 3 seconds this.responseTimeout = 10000; // 10 seconds this.callbacks = new Map(); this.disconnected = false; this.nextId = 0; this.port = null; } invoke(action, params, target) { if (this.disconnected) { return Promise.reject(new Error('Disconnected')); } if (this.port === null) { this.createPort(); } const id = `${this.nextId}`; ++this.nextId; return new Promise((resolve, reject) => { const info = {id, resolve, reject, ack: false, timer: null}; this.callbacks.set(id, info); info.timer = setTimeout(() => this.onError(id, 'Timeout (ack)'), this.ackTimeout); this.port.postMessage({id, action, params, target, senderId: this.senderId}); }); } createPort() { this.port = chrome.runtime.connect(null, {name: 'backend-api-forwarder'}); this.port.onDisconnect.addListener(this.onDisconnect.bind(this)); this.port.onMessage.addListener(this.onMessage.bind(this)); } onMessage({type, id, data, senderId}) { if (senderId !== this.senderId) { return; } switch (type) { case 'ack': this.onAck(id); break; case 'result': this.onResult(id, data); break; } } onDisconnect() { this.disconnected = true; for (const id of this.callbacks.keys()) { this.onError(id, 'Disconnected'); } } onAck(id) { const info = this.callbacks.get(id); if (typeof info === 'undefined') { console.warn(`ID ${id} not found for ack`); return; } if (info.ack) { console.warn(`Request ${id} already ack'd`); return; } info.ack = true; clearTimeout(info.timer); info.timer = setTimeout(() => this.onError(id, 'Timeout (response)'), this.responseTimeout); } onResult(id, data) { const info = this.callbacks.get(id); if (typeof info === 'undefined') { console.warn(`ID ${id} not found`); return; } if (!info.ack) { console.warn(`Request ${id} not ack'd`); return; } this.callbacks.delete(id); clearTimeout(info.timer); info.timer = null; if (typeof data.error !== 'undefined') { info.reject(jsonToError(data.error)); } else { info.resolve(data.result); } } onError(id, reason) { const info = this.callbacks.get(id); if (typeof info === 'undefined') { return; } this.callbacks.delete(id); info.timer = null; info.reject(new Error(reason)); } static generateId(length) { let id = ''; for (let i = 0; i < length; ++i) { id += Math.floor(Math.random() * 256).toString(16).padStart(2, '0'); } return id; } }