refactor(data-classes): change to get_value and update docs

- Refactor value to get_value
- Add code example

Author: Michael Brewer

aws_lambda_powertools/utilities/data_classes/dynamo_db_stream_event.py

@@ -20,7 +20,10 @@ class AttributeValueType(Enum):
 class AttributeValue(DictWrapper):
     """Represents the data for an attribute
 
-    Documentation: https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_streams_AttributeValue.html
+    Documentation:
+    --------------
+    - https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_streams_AttributeValue.html
+    - https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/HowItWorks.NamingRulesDataTypes.html
     """
 
     def __init__(self, data: Dict[str, Any]):
@@ -135,14 +138,6 @@ def get_type(self) -> AttributeValueType:
         """Get the attribute value type based on the contained data"""
         return AttributeValueType(self.dynamodb_type)
 
-    @property
-    def value(self) -> Union[Optional[bool], Optional[str], Optional[List], Optional[Dict]]:
-        """Get the attribute value"""
-        try:
-            return getattr(self, f"{self.dynamodb_type.lower()}_value")
-        except AttributeError:
-            raise TypeError(f"Dynamodb type {self.dynamodb_type} is not supported")
-
     @property
     def l_value(self) -> Optional[List["AttributeValue"]]:
         """Alias of list_value"""
@@ -153,6 +148,14 @@ def m_value(self) -> Optional[Dict[str, "AttributeValue"]]:
         """Alias of map_value"""
         return self.map_value
 
+    @property
+    def get_value(self) -> Union[Optional[bool], Optional[str], Optional[List], Optional[Dict]]:
+        """Get the attribute value"""
+        try:
+            return getattr(self, f"{self.dynamodb_type.lower()}_value")
+        except AttributeError:
+            raise TypeError(f"Dynamodb type {self.dynamodb_type} is not supported")
+
 
 def _attribute_value_dict(attr_values: Dict[str, dict], key: str) -> Optional[Dict[str, AttributeValue]]:
     """A dict of type String to AttributeValue object map
@@ -271,6 +274,31 @@ class DynamoDBStreamEvent(DictWrapper):
     Documentation:
     -------------
     - https://docs.aws.amazon.com/lambda/latest/dg/with-ddb.html
+
+    Example
+    -------
+    **Process dynamodb stream events and use get_type and get_value for handling conversions**
+
+        from aws_lambda_powertools.utilities.data_classes import event_source, DynamoDBStreamEvent
+        from aws_lambda_powertools.utilities.data_classes.dynamo_db_stream_event import (
+            AttributeValueType,
+            AttributeValue,
+        )
+        from aws_lambda_powertools.utilities.typing import LambdaContext
+
+
+        @event_source(data_class=DynamoDBStreamEvent)
+        def lambda_handler(event: DynamoDBStreamEvent, context: LambdaContext):
+            for record in event.records:
+                key: AttributeValue = record.dynamodb.keys["id"]
+                if key == AttributeValueType.Number:
+                    assert key.get_value == key.n_value
+                    print(key.get_value)
+                elif key == AttributeValueType.Map:
+                    assert key.get_value == key.map_value
+                    print(key.get_value)
+
+
     """
 
     @property

tests/functional/test_data_classes.py

@@ -450,7 +450,7 @@ def test_dynamo_attribute_value_b_value():
     attribute_value = AttributeValue(example_attribute_value)
 
     assert attribute_value.get_type == AttributeValueType.Binary
-    assert attribute_value.b_value == attribute_value.value
+    assert attribute_value.b_value == attribute_value.get_value
 
 
 def test_dynamo_attribute_value_bs_value():
@@ -459,7 +459,7 @@ def test_dynamo_attribute_value_bs_value():
     attribute_value = AttributeValue(example_attribute_value)
 
     assert attribute_value.get_type == AttributeValueType.BinarySet
-    assert attribute_value.bs_value == attribute_value.value
+    assert attribute_value.bs_value == attribute_value.get_value
 
 
 def test_dynamo_attribute_value_bool_value():
@@ -468,7 +468,7 @@ def test_dynamo_attribute_value_bool_value():
     attribute_value = AttributeValue(example_attribute_value)
 
     assert attribute_value.get_type == AttributeValueType.Boolean
-    assert attribute_value.bool_value == attribute_value.value
+    assert attribute_value.bool_value == attribute_value.get_value
 
 
 def test_dynamo_attribute_value_list_value():
@@ -480,7 +480,7 @@ def test_dynamo_attribute_value_list_value():
     assert item.s_value == "Cookies"
     assert attribute_value.get_type == AttributeValueType.List
     assert attribute_value.l_value == attribute_value.list_value
-    assert attribute_value.list_value == attribute_value.value
+    assert attribute_value.list_value == attribute_value.get_value
 
 
 def test_dynamo_attribute_value_map_value():
@@ -494,7 +494,7 @@ def test_dynamo_attribute_value_map_value():
     assert item.s_value == "Joe"
     assert attribute_value.get_type == AttributeValueType.Map
     assert attribute_value.m_value == attribute_value.map_value
-    assert attribute_value.map_value == attribute_value.value
+    assert attribute_value.map_value == attribute_value.get_value
 
 
 def test_dynamo_attribute_value_n_value():
@@ -503,7 +503,7 @@ def test_dynamo_attribute_value_n_value():
     attribute_value = AttributeValue(example_attribute_value)
 
     assert attribute_value.get_type == AttributeValueType.Number
-    assert attribute_value.n_value == attribute_value.value
+    assert attribute_value.n_value == attribute_value.get_value
 
 
 def test_dynamo_attribute_value_ns_value():
@@ -512,7 +512,7 @@ def test_dynamo_attribute_value_ns_value():
     attribute_value = AttributeValue(example_attribute_value)
 
     assert attribute_value.get_type == AttributeValueType.NumberSet
-    assert attribute_value.ns_value == attribute_value.value
+    assert attribute_value.ns_value == attribute_value.get_value
 
 
 def test_dynamo_attribute_value_null_value():
@@ -521,7 +521,7 @@ def test_dynamo_attribute_value_null_value():
     attribute_value = AttributeValue(example_attribute_value)
 
     assert attribute_value.get_type == AttributeValueType.Null
-    assert attribute_value.null_value == attribute_value.value
+    assert attribute_value.null_value == attribute_value.get_value
 
 
 def test_dynamo_attribute_value_s_value():
@@ -530,7 +530,7 @@ def test_dynamo_attribute_value_s_value():
     attribute_value = AttributeValue(example_attribute_value)
 
     assert attribute_value.get_type == AttributeValueType.String
-    assert attribute_value.s_value == attribute_value.value
+    assert attribute_value.s_value == attribute_value.get_value
 
 
 def test_dynamo_attribute_value_ss_value():
@@ -539,7 +539,7 @@ def test_dynamo_attribute_value_ss_value():
     attribute_value = AttributeValue(example_attribute_value)
 
     assert attribute_value.get_type == AttributeValueType.StringSet
-    assert attribute_value.ss_value == attribute_value.value
+    assert attribute_value.ss_value == attribute_value.get_value
 
 
 def test_dynamo_attribute_value_type_error():
@@ -548,7 +548,7 @@ def test_dynamo_attribute_value_type_error():
     attribute_value = AttributeValue(example_attribute_value)
 
     with pytest.raises(TypeError):
-        print(attribute_value.value)
+        print(attribute_value.get_value)
     with pytest.raises(ValueError):
         print(attribute_value.get_type)