Auto-Deduce Invoke Response Type (#10933)

* Auto-Deduce Invoke Response Type

This modifies the existing ChipDeviceController.SendCommand() Python API
to automatically deduce the cluster object type associated with the
response and automatically return that to the caller after successfully
deserializing the TLV into that object.

This avoids callers having to explicitly pass in an object, making it
that much easier to use.

Tests: Tested using cluster_objects.py, as well as manually
sending/receiving commands at the Python shell.

* Fix test case

* Restyle

Co-authored-by: Song Guo <songguo@google.com>

src/controller/python/chip/ChipDeviceCtrl.py

@@ -340,6 +340,12 @@ def DeviceAvailableCallback(device, err):
  return returnDevice
 
  async def SendCommand(self, nodeid: int, endpoint: int, payload: ClusterObjects.ClusterCommand, responseType=None):
+ '''
+ Send a cluster-object encapsulated command to a node and get returned a future that can be awaited upon to receive the response.
+ If a valid responseType is passed in, that will be used to deserialize the object. If not, the type will be automatically deduced
+ from the metadata received over the wire.
+ '''
+
  eventLoop = asyncio.get_running_loop()
  future = eventLoop.create_future()
 

src/controller/python/chip/clusters/Command.py

@@ -21,11 +21,13 @@
 from typing import Type
 from ctypes import CFUNCTYPE, c_char_p, c_size_t, c_void_p, c_uint32, c_uint16, c_uint8, py_object
 
-
 from .ClusterObjects import ClusterCommand
 import chip.exceptions
 import chip.interaction_model
 
+import inspect
+import sys
+
 
 @dataclass
 class CommandPath:
@@ -40,27 +42,56 @@ class Status:
  ClusterStatus: int
 
 
+def FindCommandClusterObject(isClientSideCommand: bool, path: CommandPath):
+ ''' Locates the right generated cluster object given a set of parameters.
+
+ isClientSideCommand: True if it is a client-to-server command, else False.
+ path: A CommandPath that describes the endpoint, cluster and ID of the command.
+
+ Returns the type of the cluster object if one is found. Otherwise, returns None.
+ '''
+ for clusterName, obj in inspect.getmembers(sys.modules['chip.clusters.Objects']):
+ if ('chip.clusters.Objects' in str(obj)) and inspect.isclass(obj):
+ for objName, subclass in inspect.getmembers(obj):
+ if inspect.isclass(subclass) and (('Commands') in str(subclass)):
+ for commandName, command in inspect.getmembers(subclass):
+ if inspect.isclass(command):
+ for name, field in inspect.getmembers(command):
+ if ('__dataclass_fields__' in name):
+ if (field['cluster_id'].default == path.ClusterId) and (field['command_id'].default == path.CommandId) and (field['is_client'].default == isClientSideCommand):
+ return eval('chip.clusters.Objects.' + clusterName + '.Commands.' + commandName)
+ return None
+
+
 class AsyncCommandTransaction:
  def __init__(self, future: Future, eventLoop, expectType: Type):
  self._event_loop = eventLoop
  self._future = future
  self._expect_type = expectType
 
- def _handleResponse(self, status: Status, response: bytes):
- if self._expect_type:
- try:
- self._future.set_result(self._expect_type.FromTLV(response))
- except Exception as ex:
- self._handleError(
- status, 0, ex)
- else:
+ def _handleResponse(self, path: CommandPath, status: Status, response: bytes):
+ if (len(response) == 0):
  self._future.set_result(None)
+ else:
+ # If a type hasn't been assigned, let's auto-deduce it.
+ if (self._expect_type == None):
+ self._expect_type = FindCommandClusterObject(False, path)
+
+ if self._expect_type:
+ try:
+ self._future.set_result(
+ self._expect_type.FromTLV(response))
+ except Exception as ex:
+ self._handleError(
+ status, 0, ex)
+ else:
+ self._future.set_result(None)
 
  def handleResponse(self, path: CommandPath, status: Status, response: bytes):
  self._event_loop.call_soon_threadsafe(
- self._handleResponse, status, response)
+ self._handleResponse, path, status, response)
 
- def _handleError(self, status: Status, chipError: int, exception: Exception):
+ def _handleError(self, imError: int, chipError: int, exception: Exception):
  if exception:
  self._future.set_exception(exception)
  elif chipError != 0 and chipError != 0xCA:
@@ -107,6 +138,13 @@ def _OnCommandSenderDoneCallback(closure):
 
 
 def SendCommand(future: Future, eventLoop, responseType: Type, device, commandPath: CommandPath, payload: ClusterCommand) -> int:
+ ''' Send a cluster-object encapsulated command to a device and does the following:
+ - On receipt of a successful data response, returns the cluster-object equivalent through the provided future.
+ - None (on a successful response containing no data)
+ - Raises an exception if any errors are encountered.
+
+ If no response type is provided above, the type will be automatically deduced.
+ '''
  if (responseType is not None) and (not issubclass(responseType, ClusterCommand)):
  raise ValueError("responseType must be a ClusterCommand or None")