Add a poll-notify-events request support

Author: Daisuke Baba

examples/01-read-write.json

@@ -34,7 +34,7 @@
         "crontab": "",
         "once": false,
         "x": 200,
-        "y": 260,
+        "y": 220,
         "wires": [
             [
                 "dfcf20d6.138ff"
@@ -101,13 +101,32 @@
             ]
         ]
     },
+    {
+        "id": "5525464e.999a4",
+        "type": "inject",
+        "z": "867e39b4.d517f",
+        "name": "Poll Notify Events",
+        "topic": "2a19",
+        "payload": "{\"notify\":true,\"period\":5000}",
+        "payloadType": "json",
+        "repeat": "",
+        "crontab": "",
+        "once": false,
+        "x": 200,
+        "y": 300,
+        "wires": [
+            [
+                "dfcf20d6.138ff"
+            ]
+        ]
+    },
     {
         "id": "3b98076c.99a4c8",
         "type": "Generic BLE",
         "z": "",
         "localName": "CC2650 SensorTag",
-        "address": "99:99:99:99:99:99",
-        "uuid": "00000000000000000000000000000000",
+        "address": "54:6c:0e:78:86:80",
+        "uuid": "666e850ba45c4952b8bed27a8133ecb2",
         "muteNotifyEvents": true,
         "operationTimeout": "5000",
         "characteristics": [

src/generic-ble.js

@@ -123,7 +123,7 @@ function hasPendingOperations(bleDevice) {
   if (!bleDevice) {
     return false;
   }
-  if ((bleDevice._writeRequests.length > 0) || (bleDevice._readRequests.length > 0)) {
+  if ((bleDevice._writeRequests.length > 0) || (bleDevice._readRequests.length > 0) || (bleDevice._notifyRequests.length > 0)) {
     return true;
   }
   if (bleDevice.muteNotifyEvents) {
@@ -246,14 +246,26 @@ function characteristicsTask(services, bleDevice) {
     }
     process.nextTick(loop);
   }).then(() => {
-    if (bleDevice.muteNotifyEvents) {
-      return Promise.resolve();
-    }
-    let notifiables = bleDevice.characteristics.filter(c => c.notifiable);
-    if (notifiables.length === 0) {
-      return Promise.resolve();
+    let notifiables = [];
+    let notifyRequest = bleDevice._notifyRequests.shift() || [];
+    let notifyUuidList = notifyRequest.map(c => {
+      operationTimeoutMs += c.period;
+      return c.uuid;
+    });
+    notifiables = notifyUuidList.length > 0 ?
+      characteristics.filter(c => c && notifyUuidList.indexOf(c.uuid) >= 0) : [];
+
+    if (notifyRequest.length === 0) {
+      if (bleDevice.muteNotifyEvents) {
+        return Promise.resolve();
+      }
+      operationTimeoutMs += (bleDevice.operationTimeout || BLE_OPERATION_WAIT_MS) * notifiables.length;
+      notifiables = bleDevice.characteristics.filter(c => c.notifiable);
+      if (notifiables.length === 0) {
+        return Promise.resolve();
+      }
     }
-    operationTimeoutMs += (bleDevice.operationTimeout || BLE_OPERATION_WAIT_MS) * notifiables.length;
+
     return new Promise((taskResolve, taskReject) => {
       timeout = addTimeout(() => {
         if (TRACE) {
@@ -708,6 +720,7 @@ export default function(RED) {
       this.nodes = {};
       this._writeRequests = []; // {uuid:'characteristic-uuid-to-write', data:Buffer()}
       this._readRequests = []; // {uuid:'characteristic-uuid-to-read'}
+      this._notifyRequests = []; // {uuid:'characteristic-uuid-to-subscribe', period:subscription period}
       this.operations = {
         register: (node) => {
           this.nodes[node.id] = node;
@@ -777,6 +790,31 @@ export default function(RED) {
             return { uuid: r.uuid };
           }));
           return true;
+        },
+        subscribe: (uuids='', period=3000) => {
+          uuids = uuids.split(',').map((uuid) => uuid.trim()).filter((uuid) => uuid);
+          let notifiables = this.characteristics.filter(c => {
+            if (c.notifiable) {
+              if (uuids.length === 0) {
+                return true;
+              }
+              return uuids.indexOf(c.uuid) >= 0;
+            }
+          });
+          if (TRACE) {
+            this.log(`characteristics => ${JSON.stringify(this.characteristics)}`);
+            this.log(`notifiables.length => ${notifiables.length}`);
+          }
+          if (notifiables.length === 0) {
+            return false;
+          }
+          if (this._notifyRequests.length >= MAX_REQUESTS) {
+            return false;
+          }
+          this._notifyRequests.push(notifiables.map((r) => {
+            return { uuid: r.uuid, period: period };
+          }));
+          return true;
         }
       };
       ['connected', 'disconnected', 'subscribed', 'unsubscribed', 'error', 'timeout'].forEach(ev => {
@@ -869,7 +907,18 @@ export default function(RED) {
           if (TRACE) {
             this.log(`input arrived!`);
           }
-          this.genericBleNode.operations.read(msg.topic);
+          let obj = msg.payload || {};
+          try {
+            if (typeof(obj) === 'string') {
+              obj = JSON.parse(msg.payload);
+            }
+          } catch (_) {
+          }
+          if (obj.notify) {
+            this.genericBleNode.operations.subscribe(msg.topic, obj.period);
+          } else {
+            this.genericBleNode.operations.read(msg.topic);
+          }
         });
         this.on('close', () => {
           if (this.genericBleNode) {

src/locales/en-US/generic-ble.html

@@ -20,10 +20,29 @@ <h3>Outputs</h3>
 </p>
 <h3>Inputs</h3>
 <p>
-Expects a message used for triggering <code>Read</code> operations.
+Expects a message used for triggering <code>Read</code> operation or subscribing <code>Notify</code> events.
+<dl>
+<dt>For <code>Read</code> operation:</dt>
+<dd>
 You can set one or more characteristic uuids separated by comma (CSV) to query to <code>msg.topic</code>.
 However, leave <code>msg.topic</code> empty if you want to query all readable characteristics.
-The content of the message paylaod is always <b>IGNORED</b>.
+</dd>
+<dt>For subscribing <code>Notify</code> events:</dt>
+<dd>
+In order to subscribe <code>Notify</code> events rather than reading characteristics,
+set one or more characteristic uuids separated by comma (CSV) to subscribe to <code>msg.topic</code>
+and set the following object to <code>msg.payload</code> as well.
+However, leave <code>msg.topic</code> empty if you want to subscribe all notifiable characteristics.
+<pre>
+{
+  "notify": true,
+  "period": 6000
+}
+</pre>
+When you set the above in <code>msg.payload</code>, <code>msg.topic</code> is ignored.
+The <code>period</code> property is the period for subscribing <code>Notify</code> events in milliseconds <b>per characteristic</b>.
+</dd>
+</dl>
 </p>
 </script>