Merge pull request #2182 from paulkaplan/scratch-link-socket

Initial prototype of configurable scratch link socket

src/engine/runtime.js

@@ -16,6 +16,7 @@ const maybeFormatMessage = require('../util/maybe-format-message');
 const StageLayering = require('./stage-layering');
 const Variable = require('./variable');
 const xmlEscape = require('../util/xml-escape');
+const ScratchLinkWebSocket = require('../util/scratch-link-websocket');
 
 // Virtual I/O devices.
 const Clock = require('../io/clock');
@@ -1289,6 +1290,34 @@ class Runtime extends EventEmitter {
             (result, categoryInfo) => result.concat(categoryInfo.blocks.map(blockInfo => blockInfo.json)), []);
     }
 
+    /**
+     * Get a scratch link socket.
+     * @param {string} type Either BLE or BT
+     * @returns {ScratchLinkSocket} The scratch link socket.
+     */
+    getScratchLinkSocket (type) {
+        const factory = this._linkSocketFactory || this._defaultScratchLinkSocketFactory;
+        return factory(type);
+    }
+
+    /**
+     * Configure how ScratchLink sockets are created. Factory must consume a "type" parameter
+     * either BT or BLE.
+     * @param {Function} factory The new factory for creating ScratchLink sockets.
+     */
+    configureScratchLinkSocketFactory (factory) {
+        this._linkSocketFactory = factory;
+    }
+
+    /**
+     * The default scratch link socket creator, using websockets to the installed device manager.
+     * @param {string} type Either BLE or BT
+     * @returns {ScratchLinkSocket} The new scratch link socket (a WebSocket object)
+     */
+    _defaultScratchLinkSocketFactory (type) {
+        return new ScratchLinkWebSocket(type);
+    }
+
     /**
      * Register an extension that communications with a hardware peripheral by id,
      * to have access to it and its peripheral functions in the future.

src/io/ble.js

@@ -1,8 +1,6 @@
-const JSONRPCWebSocket = require('../util/jsonrpc-web-socket');
-const ScratchLinkWebSocket = 'wss://device-manager.scratch.mit.edu:20110/scratch/ble';
-// const log = require('../util/log');
+const JSONRPC = require('../util/jsonrpc');
 
-class BLE extends JSONRPCWebSocket {
+class BLE extends JSONRPC {
 
     /**
      * A BLE peripheral socket object.  It handles connecting, over web sockets, to
@@ -14,13 +12,15 @@ class BLE extends JSONRPCWebSocket {
      * @param {object} disconnectCallback - a callback for disconnection.
      */
     constructor (runtime, extensionId, peripheralOptions, connectCallback, disconnectCallback = null) {
-        const ws = new WebSocket(ScratchLinkWebSocket);
-        super(ws);
+        super();
 
-        this._ws = ws;
-        this._ws.onopen = this.requestPeripheral.bind(this); // only call request peripheral after socket opens
-        this._ws.onerror = this._handleRequestError.bind(this, 'ws onerror');
-        this._ws.onclose = this.handleDisconnectError.bind(this, 'ws onclose');
+        this._socket = runtime.getScratchLinkSocket('BLE');
+        this._socket.setOnOpen(this.requestPeripheral.bind(this));
+        this._socket.setOnClose(this.handleDisconnectError.bind(this));
+        this._socket.setOnError(this._handleRequestError.bind(this));
+        this._socket.setHandleMessage(this._handleMessage.bind(this));
+
+        this._sendMessage = this._socket.sendMessage.bind(this._socket);
 
         this._availablePeripherals = {};
         this._connectCallback = connectCallback;
@@ -31,6 +31,8 @@ class BLE extends JSONRPCWebSocket {
         this._extensionId = extensionId;
         this._peripheralOptions = peripheralOptions;
         this._runtime = runtime;
+
+        this._socket.open();
     }
 
     /**
@@ -38,18 +40,15 @@ class BLE extends JSONRPCWebSocket {
      * 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 = {};
-            if (this._discoverTimeoutID) {
-                window.clearTimeout(this._discoverTimeoutID);
-            }
-            this._discoverTimeoutID = window.setTimeout(this._handleDiscoverTimeout.bind(this), 15000);
-            this.sendRemoteRequest('discover', this._peripheralOptions)
-                .catch(e => {
-                    this._handleRequestError(e);
-                });
+        this._availablePeripherals = {};
+        if (this._discoverTimeoutID) {
+            window.clearTimeout(this._discoverTimeoutID);
         }
-        // TODO: else?
+        this._discoverTimeoutID = window.setTimeout(this._handleDiscoverTimeout.bind(this), 15000);
+        this.sendRemoteRequest('discover', this._peripheralOptions)
+            .catch(e => {
+                this._handleRequestError(e);
+            });
     }
 
     /**
@@ -73,14 +72,14 @@ class BLE extends JSONRPCWebSocket {
      * Close the websocket.
      */
     disconnect () {
-        if (this._ws.readyState === this._ws.OPEN) {
-            this._ws.close();
-        }
-
         if (this._connected) {
             this._connected = false;
         }
 
+        if (this._socket.isOpen()) {
+            this._socket.close();
+        }
+
         if (this._discoverTimeoutID) {
             window.clearTimeout(this._discoverTimeoutID);
         }

src/io/bt.js

@@ -1,8 +1,6 @@
-const JSONRPCWebSocket = require('../util/jsonrpc-web-socket');
-const ScratchLinkWebSocket = 'wss://device-manager.scratch.mit.edu:20110/scratch/bt';
-// const log = require('../util/log');
+const JSONRPC = require('../util/jsonrpc');
 
-class BT extends JSONRPCWebSocket {
+class BT extends JSONRPC {
 
     /**
      * A BT peripheral socket object.  It handles connecting, over web sockets, to
@@ -15,13 +13,15 @@ class BT extends JSONRPCWebSocket {
      * @param {object} messageCallback - a callback for message sending.
      */
     constructor (runtime, extensionId, peripheralOptions, connectCallback, disconnectCallback = null, messageCallback) {
-        const ws = new WebSocket(ScratchLinkWebSocket);
-        super(ws);
+        super();
 
-        this._ws = ws;
-        this._ws.onopen = this.requestPeripheral.bind(this); // only call request peripheral after socket opens
-        this._ws.onerror = this._handleRequestError.bind(this, 'ws onerror');
-        this._ws.onclose = this.handleDisconnectError.bind(this, 'ws onclose');
+        this._socket = runtime.getScratchLinkSocket('BT');
+        this._socket.setOnOpen(this.requestPeripheral.bind(this));
+        this._socket.setOnError(this._handleRequestError.bind(this));
+        this._socket.setOnClose(this.handleDisconnectError.bind(this));
+        this._socket.setHandleMessage(this._handleMessage.bind(this));
+
+        this._sendMessage = this._socket.sendMessage.bind(this._socket);
 
         this._availablePeripherals = {};
         this._connectCallback = connectCallback;
@@ -33,6 +33,8 @@ class BT extends JSONRPCWebSocket {
         this._peripheralOptions = peripheralOptions;
         this._messageCallback = messageCallback;
         this._runtime = runtime;
+
+        this._socket.open();
     }
 
     /**
@@ -40,18 +42,15 @@ class BT extends JSONRPCWebSocket {
      * 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 = {};
-            if (this._discoverTimeoutID) {
-                window.clearTimeout(this._discoverTimeoutID);
-            }
-            this._discoverTimeoutID = window.setTimeout(this._handleDiscoverTimeout.bind(this), 15000);
-            this.sendRemoteRequest('discover', this._peripheralOptions)
-                .catch(
-                    e => this._handleRequestError(e)
-                );
+        this._availablePeripherals = {};
+        if (this._discoverTimeoutID) {
+            window.clearTimeout(this._discoverTimeoutID);
         }
-        // TODO: else?
+        this._discoverTimeoutID = window.setTimeout(this._handleDiscoverTimeout.bind(this), 15000);
+        this.sendRemoteRequest('discover', this._peripheralOptions)
+            .catch(
+                e => this._handleRequestError(e)
+            );
     }
 
     /**
@@ -75,14 +74,14 @@ class BT extends JSONRPCWebSocket {
      * Close the websocket.
      */
     disconnect () {
-        if (this._ws.readyState === this._ws.OPEN) {
-            this._ws.close();
-        }
-
         if (this._connected) {
             this._connected = false;
         }
 
+        if (this._socket.isOpen()) {
+            this._socket.close();
+        }
+
         if (this._discoverTimeoutID) {
             window.clearTimeout(this._discoverTimeoutID);
         }

src/util/jsonrpc-web-socket.js

@@ -1,40 +0,0 @@
-const JSONRPC = require('./jsonrpc');
-// const log = require('../util/log');
-
-class JSONRPCWebSocket extends JSONRPC {
-    constructor (webSocket) {
-        super();
-
-        this._ws = webSocket;
-        this._ws.onmessage = e => this._onSocketMessage(e);
-        this._ws.onopen = e => this._onSocketOpen(e);
-        this._ws.onclose = e => this._onSocketClose(e);
-        this._ws.onerror = e => this._onSocketError(e);
-    }
-
-    dispose () {
-        this._ws.close();
-        this._ws = null;
-    }
-
-    _onSocketOpen () {
-    }
-
-    _onSocketClose () {
-    }
-
-    _onSocketError () {
-    }
-
-    _onSocketMessage (e) {
-        const json = JSON.parse(e.data);
-        this._handleMessage(json);
-    }
-
-    _sendMessage (message) {
-        const messageText = JSON.stringify(message);
-        this._ws.send(messageText);
-    }
-}
-
-module.exports = JSONRPCWebSocket;

src/util/scratch-link-websocket.js

@@ -0,0 +1,84 @@
+/**
+ * This class provides a ScratchLinkSocket implementation using WebSockets,
+ * attempting to connect with the locally installed Scratch-Link.
+ *
+ * To connect with ScratchLink without WebSockets, you must implement all of the
+ * public methods in this class.
+ * - open()
+ * - close()
+ * - setOn[Open|Close|Error]
+ * - setHandleMessage
+ * - sendMessage(msgObj)
+ * - isOpen()
+ */
+class ScratchLinkWebSocket {
+    constructor (type) {
+        this._type = type;
+        this._onOpen = null;
+        this._onClose = null;
+        this._onError = null;
+        this._handleMessage = null;
+
+        this._ws = null;
+    }
+
+    open () {
+        switch (this._type) {
+        case 'BLE':
+            this._ws = new WebSocket('wss://device-manager.scratch.mit.edu:20110/scratch/ble');
+            break;
+        case 'BT':
+            this._ws = new WebSocket('wss://device-manager.scratch.mit.edu:20110/scratch/bt');
+            break;
+        default:
+            throw new Error(`Unknown ScratchLink socket Type: ${this._type}`);
+        }
+
+        if (this._onOpen && this._onClose && this._onError && this._handleMessage) {
+            this._ws.onopen = this._onOpen;
+            this._ws.onclose = this._onClose;
+            this._ws.onerror = this._onError;
+        } else {
+            throw new Error('Must set open, close, message and error handlers before calling open on the socket');
+        }
+
+        this._ws.onmessage = this._onMessage.bind(this);
+    }
+
+    close () {
+        this._ws.close();
+        this._ws = null;
+    }
+
+    sendMessage (message) {
+        const messageText = JSON.stringify(message);
+        this._ws.send(messageText);
+    }
+
+    setOnOpen (fn) {
+        this._onOpen = fn;
+    }
+
+    setOnClose (fn) {
+        this._onClose = fn;
+    }
+
+    setOnError (fn) {
+        this._onError = fn;
+    }
+
+    setHandleMessage (fn) {
+        this._handleMessage = fn;
+    }
+
+    isOpen () {
+        return this._ws && this._ws.readyState === this._ws.OPEN;
+    }
+
+    _onMessage (e) {
+        const json = JSON.parse(e.data);
+        this._handleMessage(json);
+    }
+}
+
+module.exports = ScratchLinkWebSocket;

src/virtual-machine.js

@@ -1525,6 +1525,14 @@ class VirtualMachine extends EventEmitter {
         }
         return null;
     }
+
+    /**
+     * Allow VM consumer to configure the ScratchLink socket creator.
+     * @param {Function} factory The custom ScratchLink socket factory.
+     */
+    configureScratchLinkSocketFactory (factory) {
+        this.runtime.configureScratchLinkSocketFactory(factory);
+    }
 }
 
 module.exports = VirtualMachine;