Attempting to fix #1492: WeDo2 use of should be backwards compatible.

scratchfoundation · Aug 22, 2018 · bfa4dfa · bfa4dfa
1 parent f4e9212
commit bfa4dfa
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Showing 2 changed files with 18 additions and 20 deletions.
diff --git a/src/extensions/scratch3_wedo2/index.js b/src/extensions/scratch3_wedo2/index.js
@@ -460,8 +460,9 @@ class WeDo2 {
     // TODO: rename scan?
     startDeviceScan () {
         this._ble = new BLESession(this._runtime, {
-            filters: [{services: [UUID.DEVICE_SERVICE]}],
-            optionalServices: [UUID.IO_SERVICE]
+            filters: [
+                {services: [UUID.DEVICE_SERVICE, UUID.IO_SERVICE]}
+            ]
         }, this._onConnect);
     }
 
@@ -516,10 +517,6 @@ class WeDo2 {
             })
             .then(() => {
                 // register for attached io notifications
-                // TODO: make backwards compatible with 'read':
-                // - try 'startNotifications'
-                // - then try 'read' with 'startNotifications' flag
-                // - then catch OSX and Windows errors
                 this._ble.startNotifications(UUID.DEVICE_SERVICE, UUID.ATTACHED_IO, this._onMessage);
             });
     }
@@ -629,10 +626,6 @@ class WeDo2 {
 
             this._send(UUID.INPUT_COMMAND, Base64Util.uint8ArrayToBase64(cmd))
                 .then(() => {
-                    // TODO: make backwards compatible with 'read':
-                    // - try 'startNotifications'
-                    // - then try 'read' with 'startNotifications' flag
-                    // - then catch OSX and Windows errors
                     this._ble.startNotifications(UUID.IO_SERVICE, UUID.INPUT_VALUES, this._onMessage);
                 });
         }

diff --git a/src/io/bleSession.js b/src/io/bleSession.js
@@ -1,5 +1,5 @@
 const JSONRPCWebSocket = require('../util/jsonrpc-web-socket');
-// const log = require('../util/log');
+const log = require('../util/log');
 const ScratchLinkWebSocket = 'wss://device-manager.scratch.mit.edu:20110/scratch/ble';
 
 class BLESession extends JSONRPCWebSocket {
@@ -115,7 +115,17 @@ class BLESession extends JSONRPCWebSocket {
             characteristicId
         };
         this._characteristicDidChangeCallback = onCharacteristicChanged;
-        return this.sendRemoteRequest('startNotifications', params);
+        return this.sendRemoteRequest('startNotifications', params)
+            .catch(() => {
+                // backwards compatibility: try read
+                this.read(serviceId, characteristicId, true, onCharacteristicChanged)
+                    .catch(e => {
+                        // if read not allowed, send error
+                        if (e.data !== 'Reading is not permitted.') { // OSX error TODO: Windows error?
+                            this._sendError(e);
+                        }
+                    });
+            });
     }
 
     /**
@@ -135,12 +145,7 @@ class BLESession extends JSONRPCWebSocket {
             params.startNotifications = true;
         }
         this._characteristicDidChangeCallback = onCharacteristicChanged;
-        return this.sendRemoteRequest('read', params)
-            .catch(e => {
-                if (e.data !== 'Reading is not permitted.') { // TODO: move this error check to extension
-                    this._sendError(e);
-                }
-            });
+        return this.sendRemoteRequest('read', params);
     }
 
     /**
@@ -166,9 +171,9 @@ class BLESession extends JSONRPCWebSocket {
             });
     }
 
-    _sendError (/* e */) {
+    _sendError (e) {
         this._connected = false;
-        // log.error(`BLESession error: ${JSON.stringify(e)}`);
+        log.error(`BLESession error: ${JSON.stringify(e)}`);
         this._runtime.emit(this._runtime.constructor.PERIPHERAL_ERROR);
     }