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livetrax/share/web_surfaces/shared/ardour.js
Luciano Iam 50ba8dea96
WebSockets: improve JS client and demo
add methods to callback.js
automatically reconnect js client on disconnection
mixer-demo do not recreate UI on reconnection
NO-OP: indentation in message.js
make client JS reconnection optional
fix mixer-demo scrolling
minor JS client refactor
improve mixer-demo readability
2020-04-17 20:15:10 +02:00

144 lines
3.6 KiB
JavaScript

/*
* 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 { ControlMixin } from './control.js';
import { MetadataMixin } from './metadata.js';
import { Message } from './message.js';
import { MessageChannel } from './channel.js';
// See ControlMixin and MetadataMixin for available APIs
// See ArdourCallback for an example callback implementation
class BaseArdourClient {
constructor () {
this._callbacks = [];
this._connected = false;
this._pendingRequest = null;
this._channel = new MessageChannel(location.host);
this._channel.onError = (error) => {
this._fireCallbacks('error', error);
};
this._channel.onMessage = (msg) => {
this._onChannelMessage(msg);
};
}
addCallbacks (callbacks) {
this._callbacks.push(callbacks);
}
async connect (autoReconnect) {
this._channel.onClose = async () => {
if (this._connected) {
this._fireCallbacks('disconnected');
this._connected = false;
}
if ((autoReconnect == null) || autoReconnect) {
await this._sleep(1000);
await this._connect();
}
};
this._connect();
}
disconnect () {
this._channel.onClose = () => {};
this._channel.close();
this._connected = false;
}
send (msg) {
this._channel.send(msg);
}
// Private methods
async _connect () {
await this._channel.open();
this._connected = true;
this._fireCallbacks('connected');
}
_send (node, addr, val) {
const msg = new Message(node, addr, val);
this.send(msg);
return msg;
}
async _sendAndReceive (node, addr, val) {
return new Promise((resolve, reject) => {
const hash = this._send(node, addr, val).hash;
this._pendingRequest = {resolve: resolve, hash: hash};
});
}
async _sendRecvSingle (node, addr, val) {
return await this._sendAndReceive (node, addr, val)[0];
}
_onChannelMessage (msg) {
if (this._pendingRequest && (this._pendingRequest.hash == msg.hash)) {
this._pendingRequest.resolve(msg.val);
this._pendingRequest = null;
} else {
this._fireCallbacks('message', msg);
this._fireCallbacks(msg.node, ...msg.addr, ...msg.val);
}
}
_fireCallbacks (name, ...args) {
// name_with_underscores -> onNameWithUnderscores
const method = 'on' + name.split('_').map((s) => {
return s[0].toUpperCase() + s.slice(1).toLowerCase();
}).join('');
for (const callbacks of this._callbacks) {
if (method in callbacks) {
callbacks[method](...args)
}
}
}
_fetchResponseStatusError (status) {
return new Error(`HTTP response status ${status}`);
}
async _sleep (t) {
return new Promise(resolve => setTimeout(resolve, 1000));
}
}
export class ArdourClient extends mixin(BaseArdourClient, ControlMixin, MetadataMixin) {}
function mixin (dstClass, ...classes) {
for (const srcClass of classes) {
for (const propName of Object.getOwnPropertyNames(srcClass.prototype)) {
if (propName != 'constructor') {
dstClass.prototype[propName] = srcClass.prototype[propName];
}
}
}
return dstClass;
}