Plumb in higher interface for dynamodb resource

Added handlers on both the intput and output of clients and resources to
automatically use TypeSerializer and TypeDeserializer. Also added the
conditonal expression builder to allow automatic use of Attr and Key classes
when condition expressions are needed.

boto3/dynamodb/transform.py

@@ -0,0 +1,188 @@
+# 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
+#
+# http://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.
+from collections import Mapping
+import functools
+
+from boto3.dynamodb.types import TypeSerializer, TypeDeserializer
+from boto3.dynamodb.conditions import ConditionBase
+from boto3.dynamodb.conditions import ConditionExpressionBuilder
+
+
+def register_high_level_interface(base_classes, **kwargs):
+    # This assumes the base class is the base resource object
+    resource_base_class = base_classes[0]
+
+    class DynamoDBHighLevelResource(resource_base_class):
+        def __init__(self, *args, **kwargs):
+            super(DynamoDBHighLevelResource, self).__init__(*args, **kwargs)
+            # Apply the handler that generates condition expressions including
+            # placeholders.
+
+            self.meta.client.meta.events.register(
+                'before-parameter-build.dynamodb',
+                transform_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',
+                transform_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', transform_attribute_value_output,
+                unique_id='dynamodb-attr-value-output')
+
+    base_classes[0] = DynamoDBHighLevelResource
+
+
+def transform_condition_expressions(params, model, **kwargs):
+    transformer = ParameterTransformer()
+    condition_builder = ConditionExpressionBuilder()
+
+    def inject_condition_expression(value, transformer, condition_builder,
+                                    original_params, model, placeholder_names,
+                                    placeholder_values,
+                                    is_key_condition=False):
+        if isinstance(value, ConditionBase):
+            # Create a conditional expression string with placeholders
+            # for the provided condition.
+            expr, attr_names, attr_values = condition_builder.build_expression(
+                value, is_key_condition=is_key_condition)
+
+            placeholder_names.update(attr_names)
+            placeholder_values.update(attr_values)
+
+            return expr
+        # Use the user provided value if it is not a ConditonBase object.
+        return value
+
+    generated_names = {}
+    generated_values = {}
+
+    # Apply transformation for conditon and key conditon expression parameters.
+    cond_exp_transformation = functools.partial(
+        inject_condition_expression, transformer=transformer,
+        condition_builder=condition_builder, original_params=params,
+        model=model, placeholder_names=generated_names,
+        placeholder_values=generated_values, is_key_condition=False)
+    transformer.transform(
+        params, model.input_shape, cond_exp_transformation,
+        'ConditionExpression')
+
+    key_exp_transformation = functools.partial(
+        inject_condition_expression, transformer=transformer,
+        condition_builder=condition_builder, original_params=params,
+        model=model, placeholder_names=generated_names,
+        placeholder_values=generated_values, is_key_condition=True)
+    transformer.transform(
+        params, model.input_shape, key_exp_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 transform_attribute_value_input(params, model, **kwargs):
+    serializer = TypeSerializer()
+    transformer = ParameterTransformer()
+    transformer.transform(
+        params, model.input_shape, serializer.serialize, 'AttributeValue')
+
+
+def transform_attribute_value_output(parsed, model, **kwargs):
+    deserializer = TypeDeserializer()
+    transformer = ParameterTransformer()
+    transformer.transform(
+        parsed, model.output_shape, deserializer.deserialize, 'AttributeValue')
+
+
+class ParameterTransformer(object):
+    """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, '_transform_%s' % type_name)(
+                model, params, transformation, target_shape)
+
+    def _transform_structure(self, model, params, transformation,
+                             target_shape):
+        if not isinstance(params, 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, 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, list):
+            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)

boto3/session.py

@@ -270,3 +270,8 @@ def _register_default_handlers(self):
             'creating-client-class.s3',
             boto3.utils.lazy_call(
                 'boto3.s3.inject.inject_s3_transfer_methods'))
+        self._session.register(
+            'creating-resource-class.dynamodb',
+            boto3.utils.lazy_call(
+                'boto3.dynamodb.transform.register_high_level_interface'),
+            unique_id='high-level-dynamodb')

tests/functional/test_dynamodb.py

@@ -0,0 +1,68 @@
+# 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
+#
+# http://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 json
+from tests import unittest, mock
+
+from botocore.vendored import requests
+
+import boto3
+from boto3.dynamodb.conditions import Attr
+
+
+class TestDynamoDB(unittest.TestCase):
+    def setUp(self):
+        self.http_response = requests.models.Response()
+        self.http_response.status_code = 200
+        self.parsed_response = {}
+        self.make_request_patch = mock.patch(
+            'botocore.endpoint.Endpoint.make_request')
+        self.make_request_mock = self.make_request_patch.start()
+        self.make_request_mock.return_value = (
+            self.http_response, self.parsed_response)
+
+    def tearDown(self):
+        self.make_request_patch.stop()
+
+    def test_resource(self):
+        dynamodb = boto3.resource('dynamodb')
+        table = dynamodb.Table('MyTable')
+        # Make sure it uses the high level interface
+        table.scan(FilterExpression=Attr('mykey').eq('myvalue'))
+        request = self.make_request_mock.call_args_list[0][0][1]
+        request_params = json.loads(request['body'])
+        self.assertEqual(
+            request_params,
+            {'TableName': 'MyTable',
+             'FilterExpression': '#n0 = :v0',
+             'ExpressionAttributeNames': {'#n0': 'mykey'},
+             'ExpressionAttributeValues': {':v0': {'S': 'myvalue'}}}
+        )
+
+    def test_client(self):
+        dynamodb = boto3.client('dynamodb')
+        # Make sure the client still uses the botocore level interface
+        dynamodb.scan(
+            TableName='MyTable',
+            FilterExpression='#n0 = :v0',
+            ExpressionAttributeNames={'#n0': 'mykey'},
+            ExpressionAttributeValues={':v0': {'S': 'myvalue'}}
+        )
+        request = self.make_request_mock.call_args_list[0][0][1]
+        request_params = json.loads(request['body'])
+        self.assertEqual(
+            request_params,
+            {'TableName': 'MyTable',
+             'FilterExpression': '#n0 = :v0',
+             'ExpressionAttributeNames': {'#n0': 'mykey'},
+             'ExpressionAttributeValues': {':v0': {'S': 'myvalue'}}}
+        )

tests/integration/__init__.py

@@ -0,0 +1,12 @@
+# 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
+#
+# http://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.