scratch-vm/src/io/bt.js
Evelyn Eastmond 2564b24d71 Differentiate peripheral errors: request vs. disconnect (#1654)
* Beginning to add differentiation for hardware disconnect alerts.

* Set connected status after error is sent.
2018-10-17 15:48:07 -04:00

143 lines
4.9 KiB
JavaScript

const JSONRPCWebSocket = require('../util/jsonrpc-web-socket');
const ScratchLinkWebSocket = 'wss://device-manager.scratch.mit.edu:20110/scratch/bt';
// const log = require('../util/log');
class BT extends JSONRPCWebSocket {
/**
* A BT peripheral socket object. It handles connecting, over web sockets, to
* BT peripherals, and reading and writing data to them.
* @param {Runtime} runtime - the Runtime for sending/receiving GUI update events.
* @param {string} extensionId - the id of the extension using this socket.
* @param {object} peripheralOptions - the list of options for peripheral discovery.
* @param {object} connectCallback - a callback for connection.
* @param {object} messageCallback - a callback for message sending.
*/
constructor (runtime, extensionId, peripheralOptions, connectCallback, messageCallback) {
const ws = new WebSocket(ScratchLinkWebSocket);
super(ws);
this._ws = ws;
this._ws.onopen = this.requestPeripheral.bind(this); // only call request peripheral after socket opens
this._ws.onerror = this._sendDisconnectError.bind(this, 'ws onerror');
this._ws.onclose = this._sendDisconnectError.bind(this, 'ws onclose');
this._availablePeripherals = {};
this._connectCallback = connectCallback;
this._connected = false;
this._characteristicDidChangeCallback = null;
this._extensionId = extensionId;
this._peripheralOptions = peripheralOptions;
this._discoverTimeoutID = null;
this._messageCallback = messageCallback;
this._runtime = runtime;
}
/**
* Request connection to the peripheral.
* If the web socket is not yet open, request when the socket promise resolves.
*/
requestPeripheral () {
if (this._ws.readyState === 1) { // is this needed since it's only called on ws.onopen?
this._availablePeripherals = {};
this._discoverTimeoutID = window.setTimeout(this._sendDiscoverTimeout.bind(this), 15000);
this.sendRemoteRequest('discover', this._peripheralOptions)
.catch(e => this._sendRequestError(e)); // never reached?
}
// TODO: else?
}
/**
* Try connecting to the input peripheral id, and then call the connect
* callback if connection is successful.
* @param {number} id - the id of the peripheral to connect to
*/
connectPeripheral (id) {
this.sendRemoteRequest('connect', {peripheralId: id})
.then(() => {
this._connected = true;
this._runtime.emit(this._runtime.constructor.PERIPHERAL_CONNECTED);
this._connectCallback();
})
.catch(e => {
this._sendRequestError(e);
});
}
/**
* Close the websocket.
*/
disconnect () {
this._ws.close();
}
/**
* @return {bool} whether the peripheral is connected.
*/
isConnected () {
return this._connected;
}
sendMessage (options) {
return this.sendRemoteRequest('send', options)
.catch(e => {
this._sendDisconnectError(e);
});
}
/**
* Handle a received call from the socket.
* @param {string} method - a received method label.
* @param {object} params - a received list of parameters.
* @return {object} - optional return value.
*/
didReceiveCall (method, params) {
// TODO: Add peripheral 'undiscover' handling
switch (method) {
case 'didDiscoverPeripheral':
this._availablePeripherals[params.peripheralId] = params;
this._runtime.emit(
this._runtime.constructor.PERIPHERAL_LIST_UPDATE,
this._availablePeripherals
);
if (this._discoverTimeoutID) {
// TODO: window?
window.clearTimeout(this._discoverTimeoutID);
}
break;
case 'didReceiveMessage':
this._messageCallback(params); // TODO: refine?
break;
default:
return 'nah';
}
}
_sendRequestError (/* e */) {
// log.error(`BT error: ${JSON.stringify(e)}`);
this._runtime.emit(this._runtime.constructor.PERIPHERAL_REQUEST_ERROR, {
message: `Scratch lost connection to`,
extensionId: this._extensionId
});
}
_sendDisconnectError (/* e */) {
// log.error(`BT error: ${JSON.stringify(e)}`);
if (!this._connected) return;
this._connected = false;
this._runtime.emit(this._runtime.constructor.PERIPHERAL_DISCONNECT_ERROR, {
message: `Scratch lost connection to`,
extensionId: this._extensionId
});
}
_sendDiscoverTimeout () {
this._runtime.emit(this._runtime.constructor.PERIPHERAL_SCAN_TIMEOUT);
}
}
module.exports = BT;