From ae2fa6e061d42f08c5c75cb215c82547246af6c8 Mon Sep 17 00:00:00 2001
From: Christian Kothe <christiankothe@gmail.com>
Date: Wed, 25 May 2022 16:13:23 -0700
Subject: [PATCH 1/2] Exposing control over return_values in Model.update()
---
pynamodb/models.py | 30 +++++++++++++++++++++---------
tests/test_model.py | 24 +++++++++++++++++++++++-
2 files changed, 44 insertions(+), 10 deletions(-)
diff --git a/pynamodb/models.py b/pynamodb/models.py
index 7d5e99161..c74ee56c5 100644
--- a/pynamodb/models.py
+++ b/pynamodb/models.py
@@ -46,7 +46,7 @@
ATTR_DEFINITIONS, ATTR_NAME, ATTR_TYPE, KEY_SCHEMA,
KEY_TYPE, ITEM, READ_CAPACITY_UNITS, WRITE_CAPACITY_UNITS,
RANGE_KEY, ATTRIBUTES, PUT, DELETE, RESPONSES,
- INDEX_NAME, PROVISIONED_THROUGHPUT, PROJECTION, ALL_NEW,
+ INDEX_NAME, PROVISIONED_THROUGHPUT, PROJECTION, ALL_NEW, NONE,
GLOBAL_SECONDARY_INDEXES, LOCAL_SECONDARY_INDEXES, KEYS,
PROJECTION_TYPE, NON_KEY_ATTRIBUTES,
TABLE_STATUS, ACTIVE, RETURN_VALUES, BATCH_GET_PAGE_LIMIT,
@@ -417,31 +417,43 @@ def delete(self, condition: Optional[Condition] = None, settings: OperationSetti
return self._get_connection().delete_item(hk_value, range_key=rk_value, condition=condition, settings=settings)
- def update(self, actions: List[Action], condition: Optional[Condition] = None, settings: OperationSettings = OperationSettings.default) -> Any:
+ def update(
+ self,
+ actions: List[Action],
+ condition: Optional[Condition] = None,
+ settings: OperationSettings = OperationSettings.default,
+ read_back: str = ALL_NEW,
+ ) -> Any:
"""
Updates an item using the UpdateItem operation.
:param actions: a list of Action updates to apply
:param condition: an optional Condition on which to update
:param settings: per-operation settings
+ :param read_back: what to read back from the DB after the update
+ ALL_NEW: read back entire object after the update (default)
+ NONE: read back nothing, local version is not updated
:raises ModelInstance.DoesNotExist: if the object to be updated does not exist
:raises pynamodb.exceptions.UpdateError: if the `condition` is not met
"""
if not isinstance(actions, list) or len(actions) == 0:
raise TypeError("the value of `actions` is expected to be a non-empty list")
+ if read_back not in (ALL_NEW, NONE):
+ raise ValueError("expected `read_back` to be `ALL_NEW` or `NONE`, but was: {}".format(return_values))
hk_value, rk_value = self._get_hash_range_key_serialized_values()
version_condition = self._handle_version_attribute(actions=actions)
if version_condition is not None:
condition &= version_condition
- data = self._get_connection().update_item(hk_value, range_key=rk_value, return_values=ALL_NEW, condition=condition, actions=actions, settings=settings)
- item_data = data[ATTRIBUTES]
- stored_cls = self._get_discriminator_class(item_data)
- if stored_cls and stored_cls != type(self):
- raise ValueError("Cannot update this item from the returned class: {}".format(stored_cls.__name__))
- self.deserialize(item_data)
- return data
+ data = self._get_connection().update_item(hk_value, range_key=rk_value, return_values=read_back, condition=condition, actions=actions, settings=settings)
+ if read_back == ALL_NEW:
+ item_data = data[ATTRIBUTES]
+ stored_cls = self._get_discriminator_class(item_data)
+ if stored_cls and stored_cls != type(self):
+ raise ValueError("Cannot update this item from the returned class: {}".format(stored_cls.__name__))
+ self.deserialize(item_data)
+ return data
def save(self, condition: Optional[Condition] = None, settings: OperationSettings = OperationSettings.default) -> Dict[str, Any]:
"""
diff --git a/tests/test_model.py b/tests/test_model.py
index 94bc1799a..a96cb6f18 100644
--- a/tests/test_model.py
+++ b/tests/test_model.py
@@ -17,7 +17,7 @@
from pynamodb.constants import (
ITEM, STRING, ALL, KEYS_ONLY, INCLUDE, REQUEST_ITEMS, UNPROCESSED_KEYS, CAMEL_COUNT,
RESPONSES, KEYS, ITEMS, LAST_EVALUATED_KEY, EXCLUSIVE_START_KEY, ATTRIBUTES, BINARY,
- UNPROCESSED_ITEMS, DEFAULT_ENCODING, MAP, LIST, NUMBER, SCANNED_COUNT,
+ UNPROCESSED_ITEMS, DEFAULT_ENCODING, MAP, LIST, NUMBER, SCANNED_COUNT, ALL_NEW, NONE
)
from pynamodb.models import Model
from pynamodb.indexes import (
@@ -921,6 +921,28 @@ def test_update(self, mock_time):
assert item.views is None
self.assertEqual({'bob'}, item.custom_aliases)
+ def test_update_readback(self):
+ self.init_table_meta(SimpleUserModel, SIMPLE_MODEL_TABLE_DATA)
+ item = SimpleUserModel(user_name='foo', is_active=True, email='original@example.com', signature='foo', views=100)
+
+ with patch(PATCH_METHOD) as req:
+ req.return_value = {}
+ item.update(
+ actions=[SimpleUserModel.email.set('changed@example.com')],
+ read_back=NONE)
+ params = {
+ 'TableName': 'SimpleModel',
+ 'Key': {'user_name': {'S': 'foo'}},
+ 'ReturnValues': 'NONE',
+ 'UpdateExpression': 'SET #0 = :0',
+ 'ExpressionAttributeNames': {'#0': 'email'},
+ 'ExpressionAttributeValues': {':0': {'S': 'changed@example.com'}},
+ 'ReturnConsumedCapacity': 'TOTAL'
+ }
+ args = req.call_args[0][1]
+ deep_eq(args, params, _assert=True)
+ assert item.email == 'original@example.com'
+
def test_update_doesnt_do_validation_on_null_attributes(self):
self.init_table_meta(CarModel, CAR_MODEL_TABLE_DATA)
item = CarModel(12345)
From bbd768b0bd1d87fd4cdc18aef73d68835a6a83b2 Mon Sep 17 00:00:00 2001
From: Christian Kothe <christiankothe@gmail.com>
Date: Wed, 25 May 2022 17:10:10 -0700
Subject: [PATCH 2/2] Fix error message
---
pynamodb/models.py | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/pynamodb/models.py b/pynamodb/models.py
index c74ee56c5..dbbfb12af 100644
--- a/pynamodb/models.py
+++ b/pynamodb/models.py
@@ -439,7 +439,7 @@ def update(
if not isinstance(actions, list) or len(actions) == 0:
raise TypeError("the value of `actions` is expected to be a non-empty list")
if read_back not in (ALL_NEW, NONE):
- raise ValueError("expected `read_back` to be `ALL_NEW` or `NONE`, but was: {}".format(return_values))
+ raise ValueError("expected `read_back` to be `ALL_NEW` or `NONE`, but was: {}".format(read_back))
hk_value, rk_value = self._get_hash_range_key_serialized_values()
version_condition = self._handle_version_attribute(actions=actions)