Leshan: Observe Objects with CompositeObserve

server/django/sensordata/serializers/composite_resource_serializer.py

@@ -15,7 +15,7 @@ class InstanceSerializer(serializers.Serializer):
     id = serializers.IntegerField(help_text="Instance Counter")
 
 
-class ValueSerializer(serializers.Serializer):
+class ObjectSerializer(serializers.Serializer):
     instances = InstanceSerializer(many=True, required=False)
     KIND_CHOICES = [
         'obj',
@@ -24,6 +24,29 @@ class ValueSerializer(serializers.Serializer):
     id = serializers.IntegerField(help_text="Object ID")
 
 
+class ValueSerializer(serializers.Serializer):
+    # Annotation for Django Rest Framework for documentation generation
+    objects = serializers.ListField(
+        child=ObjectSerializer(),
+        help_text="List of LwM2M objects"
+    )
+
+    def to_representation(self, instance):
+        ret = {}
+        for key, value in instance.items():
+            serializer = ObjectSerializer(value, context=self.context)
+            ret[key] = serializer.data
+        return ret
+
+    def to_internal_value(self, data):
+        ret = {}
+        for key, value in data.items():
+            serializer = ObjectSerializer(data=value, context=self.context)
+            serializer.is_valid(raise_exception=True)
+            ret[key] = serializer.validated_data
+        return ret
+
+
 class CompositeResourceSerializer(HandleResourceMixin, serializers.Serializer):
     ep = serializers.CharField(max_length=255, help_text="Unique LwM2M Endpoint")
     val = ValueSerializer()
@@ -34,19 +57,15 @@ def create(self, validated_data):
 
         endpoint, _ = Endpoint.objects.get_or_create(endpoint=ep)
 
-        # Check if value is an object with instances (Composite resource)
-        if val['kind'] == 'obj':
-            obj_id = val.get('id')
-            for instance in val['instances']:
+        for _, obj in val.items():
+            obj_id = obj.get('id')
+            for instance in obj['instances']:
                 for resource in instance['resources']:
                     try:
                         self.handle_resource(endpoint, obj_id, resource)
                     except serializers.ValidationError as e:
                         # Re-raise the validation error to be handled by
                         # Django's validation system
                         raise e
-        else:
-            logger.error("Expected composite resource data.")
-            raise serializers.ValidationError("Expected composite resource data.")
 
         return endpoint

server/leshan/src/main/java/lwm2m/LeshanSvr.java

@@ -12,8 +12,10 @@
 import org.eclipse.leshan.core.observation.CompositeObservation;
 import org.eclipse.leshan.core.observation.SingleObservation;
 import org.eclipse.leshan.core.request.ObserveRequest;
+import org.eclipse.leshan.core.request.ObserveCompositeRequest;
 import org.eclipse.leshan.core.response.ObserveCompositeResponse;
 import org.eclipse.leshan.core.response.ObserveResponse;
+import org.eclipse.leshan.core.request.ContentFormat;
 import org.eclipse.leshan.server.send.SendListener;
 import org.eclipse.leshan.core.request.SendRequest;
 import org.eclipse.leshan.core.request.ReadRequest;
@@ -189,10 +191,13 @@ private void onboardingDevice(Registration registration) {
             try {
                 ReadResponse readResp = server.send(registration, new ReadRequest(3));
                 if (readResp.isSuccess()) {
+                    /* Match the additional hierachiy of the observe response format */
                     mapper.enable(SerializationFeature.INDENT_OUTPUT);
                     ObjectNode node = mapper.createObjectNode();
                     node.put("ep", registration.getEndpoint());
-                    node.set("val", mapper.valueToTree(readResp.getContent()));
+                    ObjectNode valNode = mapper.createObjectNode();
+                    valNode.set("/3", mapper.valueToTree(readResp.getContent()));
+                    node.set("val", valNode);
 
                     dataSenderRest.sendData(ApiPath.COMPOSITE_RES, node);
                 } else {
@@ -204,12 +209,49 @@ private void onboardingDevice(Registration registration) {
                 e.printStackTrace();
             }
 
-            /* Subscribe to individual objects */
-            int[][] objectLinks = {{3303, 0, 5700}, {3304, 0, 5701}, {3305, 0, 5702}};
-            for (int[] link : objectLinks) {
-                ObserveRequest observeRequest = new ObserveRequest(link[0], link[1], link[2]);
+            /* Subscribe to single resource instances as an example
+             * 3303: Temperature Sensor
+             */
+            int[][] singleObjectLinks = {
+                {3303, 0, 5700}
+            };
+
+            for (int[] link : singleObjectLinks) {
+                try {
+                    ObserveRequest singleRequest = new ObserveRequest(link[0], link[2]);
+
+                    log.trace("Sending ObserveRequest: " + singleRequest);
+                    server.send(registration, singleRequest);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+            }
+
+            /* Subscribe to composite object instances as an example
+             * 10300: Custom Object Instance
+             */
+            int[][] compositeObjectLinks = {
+                {10300}
+            };
+
+            for (int[] link : compositeObjectLinks) {
                 try {
-                    server.send(registration, observeRequest);
+                    List<LwM2mPath> paths = new ArrayList<>();
+                    paths.add(new LwM2mPath(link[0]));
+
+                    // Specify the content formats
+                    ContentFormat requestContentFormat = ContentFormat.SENML_CBOR;
+                    ContentFormat responseContentFormat = ContentFormat.SENML_CBOR;
+
+                    // Create the ObserveCompositeRequest for the whole object instance
+                    ObserveCompositeRequest observeCompositeRequest = new ObserveCompositeRequest(
+                        requestContentFormat,
+                        responseContentFormat,
+                        paths
+                    );
+
+                    log.trace("Sending ObserveCompositeRequest: " + observeCompositeRequest);
+                    server.send(registration, observeCompositeRequest);
                 } catch (InterruptedException e) {
                     e.printStackTrace();
                 }