feat: Allow reading value to be null

Allow reading value to be null

Signed-off-by: bruce <[email protected]>

internal/transformer/transform.go

@@ -154,6 +154,8 @@ func commandValueToReading(cv *models.CommandValue, deviceName, profileName, med
 		reading = dtos.NewBinaryReading(profileName, deviceName, cv.DeviceResourceName, binary, mediaType)
 	} else if cv.Type == common.ValueTypeObject {
 		reading = dtos.NewObjectReading(profileName, deviceName, cv.DeviceResourceName, cv.Value)
+	} else if cv.Type == common.ValueTypeObjectArray {
+		reading = dtos.NewObjectReadingWithArray(profileName, deviceName, cv.DeviceResourceName, cv.Value)
 	} else {
 		reading, err = dtos.NewSimpleReading(profileName, deviceName, cv.DeviceResourceName, cv.Type, cv.Value)
 		if err != nil {

internal/transformer/transformresult.go

@@ -398,6 +398,9 @@ func transformReadShift(value any, shift int64) (any, errors.EdgeX) {
 }
 
 func commandValueForTransform(cv *sdkModels.CommandValue) (interface{}, errors.EdgeX) {
+	if cv.Value == nil {
+		return nil, nil
+	}
 	var v interface{}
 	var err error
 	switch cv.Type {

pkg/models/commandvalue.go

@@ -442,6 +442,9 @@ func (cv *CommandValue) Float64ArrayValue() ([]float64, error) {
 
 // BinaryValue returns the value in []byte data type, and returns error if the Type is not Binary.
 func (cv *CommandValue) BinaryValue() ([]byte, error) {
+	if cv.Value == nil {
+		return nil, nil
+	}
 	var value []byte
 	if cv.Type != common.ValueTypeBinary {
 		errMsg := fmt.Sprintf("cannot convert %s to %s", cv.Type, common.ValueTypeBinary)
@@ -467,6 +470,9 @@ func (cv *CommandValue) ObjectValue() (interface{}, error) {
 // validate checks if the given value can be converted to specified valueType by
 // performing type assertion
 func validate(valueType string, value interface{}) error {
+	if value == nil {
+		return nil // value can be nil, skip validation
+	}
 	var ok bool
 	switch valueType {
 	case common.ValueTypeString: