| Current File : //usr/lib/python3/dist-packages/boto3/dynamodb/transform.py |
# Copyright 2015 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
# https://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.
import copy
from boto3.compat import collections_abc
from boto3.docs.utils import DocumentModifiedShape
from boto3.dynamodb.conditions import ConditionBase, ConditionExpressionBuilder
from boto3.dynamodb.types import TypeDeserializer, TypeSerializer
def register_high_level_interface(base_classes, **kwargs):
base_classes.insert(0, DynamoDBHighLevelResource)
class _ForgetfulDict(dict):
"""A dictionary that discards any items set on it. For use as `memo` in
`copy.deepcopy()` when every instance of a repeated object in the deepcopied
data structure should result in a separate copy.
"""
def __setitem__(self, key, value):
pass
def copy_dynamodb_params(params, **kwargs):
return copy.deepcopy(params, memo=_ForgetfulDict())
class DynamoDBHighLevelResource:
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
# Apply handler that creates a copy of the user provided dynamodb
# item such that it can be modified.
self.meta.client.meta.events.register(
'provide-client-params.dynamodb',
copy_dynamodb_params,
unique_id='dynamodb-create-params-copy',
)
self._injector = TransformationInjector()
# Apply the handler that generates condition expressions including
# placeholders.
self.meta.client.meta.events.register(
'before-parameter-build.dynamodb',
self._injector.inject_condition_expressions,
unique_id='dynamodb-condition-expression',
)
# Apply the handler that serializes the request from python
# types to dynamodb types.
self.meta.client.meta.events.register(
'before-parameter-build.dynamodb',
self._injector.inject_attribute_value_input,
unique_id='dynamodb-attr-value-input',
)
# Apply the handler that deserializes the response from dynamodb
# types to python types.
self.meta.client.meta.events.register(
'after-call.dynamodb',
self._injector.inject_attribute_value_output,
unique_id='dynamodb-attr-value-output',
)
# Apply the documentation customizations to account for
# the transformations.
attr_value_shape_docs = DocumentModifiedShape(
'AttributeValue',
new_type='valid DynamoDB type',
new_description=(
'- The value of the attribute. The valid value types are '
'listed in the '
':ref:`DynamoDB Reference Guide<ref_valid_dynamodb_types>`.'
),
new_example_value=(
'\'string\'|123|Binary(b\'bytes\')|True|None|set([\'string\'])'
'|set([123])|set([Binary(b\'bytes\')])|[]|{}'
),
)
key_expression_shape_docs = DocumentModifiedShape(
'KeyExpression',
new_type=(
'condition from :py:class:`boto3.dynamodb.conditions.Key` '
'method'
),
new_description=(
'The condition(s) a key(s) must meet. Valid conditions are '
'listed in the '
':ref:`DynamoDB Reference Guide<ref_dynamodb_conditions>`.'
),
new_example_value='Key(\'mykey\').eq(\'myvalue\')',
)
con_expression_shape_docs = DocumentModifiedShape(
'ConditionExpression',
new_type=(
'condition from :py:class:`boto3.dynamodb.conditions.Attr` '
'method'
),
new_description=(
'The condition(s) an attribute(s) must meet. Valid conditions '
'are listed in the '
':ref:`DynamoDB Reference Guide<ref_dynamodb_conditions>`.'
),
new_example_value='Attr(\'myattribute\').eq(\'myvalue\')',
)
self.meta.client.meta.events.register(
'docs.*.dynamodb.*.complete-section',
attr_value_shape_docs.replace_documentation_for_matching_shape,
unique_id='dynamodb-attr-value-docs',
)
self.meta.client.meta.events.register(
'docs.*.dynamodb.*.complete-section',
key_expression_shape_docs.replace_documentation_for_matching_shape,
unique_id='dynamodb-key-expression-docs',
)
self.meta.client.meta.events.register(
'docs.*.dynamodb.*.complete-section',
con_expression_shape_docs.replace_documentation_for_matching_shape,
unique_id='dynamodb-cond-expression-docs',
)
class TransformationInjector:
"""Injects the transformations into the user provided parameters."""
def __init__(
self,
transformer=None,
condition_builder=None,
serializer=None,
deserializer=None,
):
self._transformer = transformer
if transformer is None:
self._transformer = ParameterTransformer()
self._condition_builder = condition_builder
if condition_builder is None:
self._condition_builder = ConditionExpressionBuilder()
self._serializer = serializer
if serializer is None:
self._serializer = TypeSerializer()
self._deserializer = deserializer
if deserializer is None:
self._deserializer = TypeDeserializer()
def inject_condition_expressions(self, params, model, **kwargs):
"""Injects the condition expression transformation into the parameters
This injection includes transformations for ConditionExpression shapes
and KeyExpression shapes. It also handles any placeholder names and
values that are generated when transforming the condition expressions.
"""
self._condition_builder.reset()
generated_names = {}
generated_values = {}
# Create and apply the Condition Expression transformation.
transformation = ConditionExpressionTransformation(
self._condition_builder,
placeholder_names=generated_names,
placeholder_values=generated_values,
is_key_condition=False,
)
self._transformer.transform(
params, model.input_shape, transformation, 'ConditionExpression'
)
# Create and apply the Key Condition Expression transformation.
transformation = ConditionExpressionTransformation(
self._condition_builder,
placeholder_names=generated_names,
placeholder_values=generated_values,
is_key_condition=True,
)
self._transformer.transform(
params, model.input_shape, transformation, 'KeyExpression'
)
expr_attr_names_input = 'ExpressionAttributeNames'
expr_attr_values_input = 'ExpressionAttributeValues'
# Now that all of the condition expression transformation are done,
# update the placeholder dictionaries in the request.
if expr_attr_names_input in params:
params[expr_attr_names_input].update(generated_names)
else:
if generated_names:
params[expr_attr_names_input] = generated_names
if expr_attr_values_input in params:
params[expr_attr_values_input].update(generated_values)
else:
if generated_values:
params[expr_attr_values_input] = generated_values
def inject_attribute_value_input(self, params, model, **kwargs):
"""Injects DynamoDB serialization into parameter input"""
self._transformer.transform(
params,
model.input_shape,
self._serializer.serialize,
'AttributeValue',
)
def inject_attribute_value_output(self, parsed, model, **kwargs):
"""Injects DynamoDB deserialization into responses"""
if model.output_shape is not None:
self._transformer.transform(
parsed,
model.output_shape,
self._deserializer.deserialize,
'AttributeValue',
)
class ConditionExpressionTransformation:
"""Provides a transformation for condition expressions
The ``ParameterTransformer`` class can call this class directly
to transform the condition expressions in the parameters provided.
"""
def __init__(
self,
condition_builder,
placeholder_names,
placeholder_values,
is_key_condition=False,
):
self._condition_builder = condition_builder
self._placeholder_names = placeholder_names
self._placeholder_values = placeholder_values
self._is_key_condition = is_key_condition
def __call__(self, value):
if isinstance(value, ConditionBase):
# Create a conditional expression string with placeholders
# for the provided condition.
built_expression = self._condition_builder.build_expression(
value, is_key_condition=self._is_key_condition
)
self._placeholder_names.update(
built_expression.attribute_name_placeholders
)
self._placeholder_values.update(
built_expression.attribute_value_placeholders
)
return built_expression.condition_expression
# Use the user provided value if it is not a ConditonBase object.
return value
class ParameterTransformer:
"""Transforms the input to and output from botocore based on shape"""
def transform(self, params, model, transformation, target_shape):
"""Transforms the dynamodb input to or output from botocore
It applies a specified transformation whenever a specific shape name
is encountered while traversing the parameters in the dictionary.
:param params: The parameters structure to transform.
:param model: The operation model.
:param transformation: The function to apply the parameter
:param target_shape: The name of the shape to apply the
transformation to
"""
self._transform_parameters(model, params, transformation, target_shape)
def _transform_parameters(
self, model, params, transformation, target_shape
):
type_name = model.type_name
if type_name in ('structure', 'map', 'list'):
getattr(self, f'_transform_{type_name}')(
model, params, transformation, target_shape
)
def _transform_structure(
self, model, params, transformation, target_shape
):
if not isinstance(params, collections_abc.Mapping):
return
for param in params:
if param in model.members:
member_model = model.members[param]
member_shape = member_model.name
if member_shape == target_shape:
params[param] = transformation(params[param])
else:
self._transform_parameters(
member_model,
params[param],
transformation,
target_shape,
)
def _transform_map(self, model, params, transformation, target_shape):
if not isinstance(params, collections_abc.Mapping):
return
value_model = model.value
value_shape = value_model.name
for key, value in params.items():
if value_shape == target_shape:
params[key] = transformation(value)
else:
self._transform_parameters(
value_model, params[key], transformation, target_shape
)
def _transform_list(self, model, params, transformation, target_shape):
if not isinstance(params, collections_abc.MutableSequence):
return
member_model = model.member
member_shape = member_model.name
for i, item in enumerate(params):
if member_shape == target_shape:
params[i] = transformation(item)
else:
self._transform_parameters(
member_model, params[i], transformation, target_shape
)