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