Add IDE messaging support to extensions API. Close #1406

src/extensions.js

@@ -76,6 +76,12 @@
             this.registry.forEach(ext => ext.onSetStageSize(width, height));
         }
 
+        onMessage(type, data) {
+          this.registry
+              .flatMap(ext => ext.getMessageHandlers(type))
+              .forEach(fn => fn(data))
+        }
+
         register(Extension) {
             if (this.isReady()) {
                 this.load(Extension);
@@ -185,6 +191,7 @@
 
     function Extension (name) {
         this.name = name;
+        this._handlers = {};
     }
 
     Extension.prototype.getMenu = function() {
@@ -211,6 +218,25 @@
         return [];
     };
 
+    Extension.prototype.addMessageListener = function(type, fn) {
+        if (!this._handlers[type]) {
+            this._handlers[type] = [];
+        }
+        this._handlers[type].push(fn);
+    };
+
+    Extension.prototype.removeMessageListener = function(type, fn) {
+        const handlers = this.getMessageHandlers(type);
+        const index = handlers.indexOf(fn);
+        if (index > -1) {
+            handlers.splice(index, 1);
+        }
+    };
+
+    Extension.prototype.getMessageHandlers = function(type) {
+      return this._handlers[type] || [];
+    };
+
     Extension.prototype.onRunScripts =
     Extension.prototype.onStopAllScripts =
     Extension.prototype.onPauseAll =

src/websockets.js

@@ -176,6 +176,10 @@ WebSocketManager.IDEMessageHandlers = {
 };
 
 WebSocketManager.MessageHandlers = {
+    'extension': function(msg) {
+        const {type, data} = msg.data;
+        NetsBloxExtensions.onMessage(type, data);
+    },
     'ide-message': function(msg) {
         const {data, sender} = msg;
         let response, error;

test/extensions.spec.js

@@ -373,4 +373,29 @@ describe('extensions', function() {
             assert(w == 123 && h == 456);
         });
     });
+
+    describe('messages', function () {
+        it('should pass recvd messages to ext', function(done) {
+            const {NetsBloxExtensions} = driver.globals();
+            const extension = NetsBloxExtensions.registry[0];
+            const payload = "hello there!";
+            extension.addMessageListener('test', data => {
+                console.log("hello?")
+                const err = data !== payload ?
+                  new Error("Incorrect data payload: " + data) : null;
+                done(err);
+            });
+
+            // spoof receiving the message
+            const msg = {
+                type: 'extension',
+                data: {
+                    type: 'test',
+                    data: payload,
+                },
+            };
+            const rawMsg = {data: JSON.stringify(msg)};
+            driver.ide().sockets.websocket.onmessage(rawMsg);
+        });
+    });
 });