Rebuilt shadow bindings and updated shadow sample to show how to clear properties (#269)

* Rebuilt shadow bindings and updated shadow sample to show how to clear properties
* Modified Shadow sample to fit model generator adjustments that allow passing None as valid input
* Adjusted iotshadow so that the none_is_valid properties default to False
* Minor adjustments to passing None in Shadow
* Updated variable_is_null_valid to variable_is_nullable for better readability. Added setting _is_nullable to from_payload

Author: TwistedTwigleg

awsiot/iotshadow.py

@@ -765,8 +765,10 @@ def __init__(self, *args, **kwargs):
     def to_payload(self):
         # type: () -> typing.Dict[str, typing.Any]
         payload = {} # type: typing.Dict[str, typing.Any]
+
         if self.client_token is not None:
             payload['clientToken'] = self.client_token
+
         return payload
 
 class DeleteNamedShadowSubscriptionRequest(awsiot.ModeledClass):
@@ -824,8 +826,10 @@ def __init__(self, *args, **kwargs):
     def to_payload(self):
         # type: () -> typing.Dict[str, typing.Any]
         payload = {} # type: typing.Dict[str, typing.Any]
+
         if self.client_token is not None:
             payload['clientToken'] = self.client_token
+
         return payload
 
 class DeleteShadowResponse(awsiot.ModeledClass):
@@ -977,8 +981,10 @@ def __init__(self, *args, **kwargs):
     def to_payload(self):
         # type: () -> typing.Dict[str, typing.Any]
         payload = {} # type: typing.Dict[str, typing.Any]
+
         if self.client_token is not None:
             payload['clientToken'] = self.client_token
+
         return payload
 
 class GetNamedShadowSubscriptionRequest(awsiot.ModeledClass):
@@ -1036,8 +1042,10 @@ def __init__(self, *args, **kwargs):
     def to_payload(self):
         # type: () -> typing.Dict[str, typing.Any]
         payload = {} # type: typing.Dict[str, typing.Any]
+
         if self.client_token is not None:
             payload['clientToken'] = self.client_token
+
         return payload
 
 class GetShadowResponse(awsiot.ModeledClass):
@@ -1295,15 +1303,22 @@ class ShadowState(awsiot.ModeledClass):
 
     Attributes:
         desired (typing.Dict[str, typing.Any]): The desired shadow state (from external services and devices).
+        desired_is_nullable (bool): Set to true to allow 'desired' to be None, clearing the data if sent.
+
         reported (typing.Dict[str, typing.Any]): The (last) reported shadow state from the device.
+        reported_is_nullable (bool): Set to true to allow 'reported' to be None, clearing the data if sent.
+
     """
 
-    __slots__ = ['desired', 'reported']
+    __slots__ = ['desired', 'desired_is_nullable', 'reported', 'reported_is_nullable']
 
     def __init__(self, *args, **kwargs):
         self.desired = kwargs.get('desired')
         self.reported = kwargs.get('reported')
 
+        self.desired_is_nullable = kwargs.get('desired_is_nullable', False)
+        self.reported_is_nullable = kwargs.get('reported_is_nullable', False)
+
         # for backwards compatibility, read any arguments that used to be accepted by position
         for key, val in zip(['desired', 'reported'], args):
             setattr(self, key, val)
@@ -1318,15 +1333,28 @@ def from_payload(cls, payload):
         val = payload.get('reported')
         if val is not None:
             new.reported = val
+        if new.desired == None:
+            new.desired_is_nullable = True
+        if new.reported == None:
+            new.reported_is_nullable = True
         return new
 
     def to_payload(self):
         # type: () -> typing.Dict[str, typing.Any]
         payload = {} # type: typing.Dict[str, typing.Any]
-        if self.desired is not None:
+
+        if self.desired_is_nullable is True:
             payload['desired'] = self.desired
-        if self.reported is not None:
+        else:
+            if self.desired is not None:
+                payload['desired'] = self.desired
+
+        if self.reported_is_nullable is True:
             payload['reported'] = self.reported
+        else:
+            if self.reported is not None:
+                payload['reported'] = self.reported
+
         return payload
 
 class ShadowStateWithDelta(awsiot.ModeledClass):
@@ -1522,12 +1550,16 @@ def __init__(self, *args, **kwargs):
     def to_payload(self):
         # type: () -> typing.Dict[str, typing.Any]
         payload = {} # type: typing.Dict[str, typing.Any]
+
         if self.client_token is not None:
             payload['clientToken'] = self.client_token
+
         if self.state is not None:
             payload['state'] = self.state.to_payload()
+
         if self.version is not None:
             payload['version'] = self.version
+
         return payload
 
 class UpdateNamedShadowSubscriptionRequest(awsiot.ModeledClass):
@@ -1591,12 +1623,16 @@ def __init__(self, *args, **kwargs):
     def to_payload(self):
         # type: () -> typing.Dict[str, typing.Any]
         payload = {} # type: typing.Dict[str, typing.Any]
+
         if self.client_token is not None:
             payload['clientToken'] = self.client_token
+
         if self.state is not None:
             payload['state'] = self.state.to_payload()
+
         if self.version is not None:
             payload['version'] = self.version
+
         return payload
 
 class UpdateShadowResponse(awsiot.ModeledClass):

samples/shadow.py

@@ -192,10 +192,16 @@ def on_update_shadow_accepted(response):
                 return
 
         try:
-            print("Finished updating reported shadow value to '{}'.".format(response.state.reported[shadow_property])) # type: ignore
+            if response.state.reported != None:
+                if shadow_property in response.state.reported:
+                    print("Finished updating reported shadow value to '{}'.".format(response.state.reported[shadow_property])) # type: ignore
+                else:
+                    print ("Could not find shadow property with name: '{}'.".format(shadow_property)) # type: ignore
+            else:
+                print("Shadow states cleared.") # when the shadow states are cleared, reported and desired are set to None
             print("Enter desired value: ") # remind user they can input new values
         except:
-            exit("Updated shadow is missing the target property.")
+            exit("Updated shadow is missing the target property")
 
     except Exception as e:
         exit(e)
@@ -238,14 +244,32 @@ def change_shadow_value(value):
         # any "response" messages received on the /accepted and /rejected topics
         token = str(uuid4())
 
-        request = iotshadow.UpdateShadowRequest(
+        # if the value is "clear shadow" then send a UpdateShadowRequest with None
+        # for both reported and desired to clear the shadow document completely
+        # of both.
+        if value == "clear_shadow":
+            tmp_state = iotshadow.ShadowState(reported=None, desired=None, reported_is_nullable=True, desired_is_nullable=True)
+            request = iotshadow.UpdateShadowRequest(
+                thing_name=thing_name,
+                state=tmp_state,
+                client_token=token,
+            )
+        # Otherwise, send a normal update request
+        else:
+            # if the value is "none" then set it to a Python none object to
+            # clear the individual shadow property
+            if value == "none":
+                value = None
+
+            request = iotshadow.UpdateShadowRequest(
             thing_name=thing_name,
             state=iotshadow.ShadowState(
                 reported={ shadow_property: value },
                 desired={ shadow_property: value },
-            ),
-            client_token=token,
-        )
+                ),
+                client_token=token,
+            )
+        
         future = shadow_client.publish_update_shadow(request, mqtt.QoS.AT_LEAST_ONCE)
 
         locked_data.request_tokens.add(token)