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livetrax/share/web_surfaces/shared/base/channel.js

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/*
* Copyright © 2020 Luciano Iam <lucianito@gmail.com>
*
* 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 2 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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
import { Message } from './protocol.js';
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export default class MessageChannel {
constructor (host) {
// https://developer.mozilla.org/en-US/docs/Web/API/URL/host
this._host = host;
this._pending = null;
}
async open () {
return new Promise((resolve, reject) => {
this._socket = new WebSocket(`ws://${this._host}`);
this._socket.onclose = () => this.onClose();
this._socket.onerror = (error) => this.onError(error);
this._socket.onmessage = (event) => {
const msg = Message.fromJsonText(event.data);
if (this._pending && (this._pending.nodeAddrId == msg.nodeAddrId)) {
this._pending.resolve(msg);
this._pending = null;
} else {
this.onMessage(msg, true);
}
};
this._socket.onopen = resolve;
});
}
close () {
this._socket.close();
if (this._pending) {
this._pending.reject(Error('MessageChannel: socket closed awaiting response'));
this._pending = null;
}
}
send (msg) {
if (this._socket) {
this._socket.send(msg.toJsonText());
this.onMessage(msg, false);
} else {
this.onError(Error('MessageChannel: cannot call send() before open()'));
}
}
async sendAndReceive (msg) {
return new Promise((resolve, reject) => {
this._pending = {resolve: resolve, reject: reject, nodeAddrId: msg.nodeAddrId};
this.send(msg);
});
}
onClose () {}
onError (error) {}
onMessage (msg, inbound) {}
}