120 lines
4.0 KiB
JavaScript
120 lines
4.0 KiB
JavaScript
//---------------------------------------------------------------------------
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// @syndicate-lang/driver-websocket, WebSocket client support for Syndicate/js
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// Copyright (C) 2016-2018 Tony Garnock-Jones <tonyg@leastfixedpoint.com>
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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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import { currentFacet, Bytes, Observe, Dataspace } from "@syndicate-lang/core";
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const { sleep } = activate require("@syndicate-lang/driver-timer");
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const debugFactory = require('debug');
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const _WebSocket = require('isomorphic-ws');
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assertion type WebSocket(id, url, options);
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message type DataIn(id, chunk);
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message type DataOut(id, chunk);
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Object.assign(module.exports, {
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WebSocket, DataIn, DataOut,
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});
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spawn named 'WebSocketFactory' {
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during Observe(WebSocket($id, $url, $options)) spawn named ['WebSocket', id, url] {
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const facet = currentFacet();
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const debug = debugFactory('syndicate/driver-websocket:' + (id && id.toString()));
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let finish = Dataspace.backgroundTask();
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on stop finish();
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const DEFAULT_RECONNECT_DELAY = 1000; // milliseconds
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const MAX_RECONNECT_DELAY = 30000; // milliseconds
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let ws = null;
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field this.connected = false;
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field this.reconnectDelay = DEFAULT_RECONNECT_DELAY;
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const guard = (context, f) => {
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try {
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f()
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} catch (e) {
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// Swallow e, which will be some kind of websocket-related exception.
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debug('exception in actor '+facet.actor.toString()+' during '+context+':', e.message);
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facet.stop();
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}
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};
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const connect = () => {
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disconnect();
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debug(url, 'connecting');
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ws = new _WebSocket(url, [], options.toJS());
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ws.onerror = Dataspace.wrapExternal((e) => {
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debug(url, e.message);
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disconnect();
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if (this.reconnectDelay !== DEFAULT_RECONNECT_DELAY) {
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debug('Will reconnect in '+Math.floor(this.reconnectDelay)+' milliseconds');
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}
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sleep(Math.floor(this.reconnectDelay), connect);
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this.reconnectDelay = this.reconnectDelay * 1.618 + (Math.random() * 1000);
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this.reconnectDelay =
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this.reconnectDelay > MAX_RECONNECT_DELAY
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? MAX_RECONNECT_DELAY + (Math.random() * 1000)
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: this.reconnectDelay;
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});
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ws.onopen = Dataspace.wrapExternal(() => {
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this.connected = true;
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this.reconnectDelay = DEFAULT_RECONNECT_DELAY;
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});
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ws.onclose = Dataspace.wrapExternal(() => {
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if (this.connected) {
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connect();
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}
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});
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ws.onmessage = Dataspace.wrapExternal((data) => {
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if (typeof Blob !== 'undefined' && data.data instanceof Blob) {
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var reader = new FileReader();
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reader.addEventListener("loadend", Dataspace.wrapExternal(() => {
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send DataIn(id, Bytes.from(reader.result));
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}));
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reader.readAsArrayBuffer(data.data);
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} else {
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send DataIn(id, Bytes.fromIO(data.data));
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}
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});
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};
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const disconnect = () => {
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if (ws) {
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debug(url, 'disconnecting');
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guard('close', () => ws.close());
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ws = null;
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}
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this.connected = false;
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};
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on start connect();
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on stop disconnect();
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assert WebSocket(id, url, options) when (this.connected);
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on message DataOut(id, $data) {
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if (this.connected) {
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guard('send', () => ws.send(Bytes.toIO(data)));
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}
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}
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}
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}
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