Source code for boto3.resources.response

# Copyright 2014 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 jmespath
from botocore import xform_name

from .params import get_data_member


[docs]def all_not_none(iterable): """ Return True if all elements of the iterable are not None (or if the iterable is empty). This is like the built-in ``all``, except checks against None, so 0 and False are allowable values. """ for element in iterable: if element is None: return False return True
[docs]def build_identifiers(identifiers, parent, params=None, raw_response=None): """ Builds a mapping of identifier names to values based on the identifier source location, type, and target. Identifier values may be scalars or lists depending on the source type and location. :type identifiers: list :param identifiers: List of :py:class:`~boto3.resources.model.Parameter` definitions :type parent: ServiceResource :param parent: The resource instance to which this action is attached. :type params: dict :param params: Request parameters sent to the service. :type raw_response: dict :param raw_response: Low-level operation response. :rtype: list :return: An ordered list of ``(name, value)`` identifier tuples. """ results = [] for identifier in identifiers: source = identifier.source target = identifier.target if source == 'response': value = jmespath.search(identifier.path, raw_response) elif source == 'requestParameter': value = jmespath.search(identifier.path, params) elif source == 'identifier': value = getattr(parent, xform_name(identifier.name)) elif source == 'data': # If this is a data member then it may incur a load # action before returning the value. value = get_data_member(parent, identifier.path) elif source == 'input': # This value is set by the user, so ignore it here continue else: raise NotImplementedError(f'Unsupported source type: {source}') results.append((xform_name(target), value)) return results
[docs]def build_empty_response(search_path, operation_name, service_model): """ Creates an appropriate empty response for the type that is expected, based on the service model's shape type. For example, a value that is normally a list would then return an empty list. A structure would return an empty dict, and a number would return None. :type search_path: string :param search_path: JMESPath expression to search in the response :type operation_name: string :param operation_name: Name of the underlying service operation. :type service_model: :ref:`botocore.model.ServiceModel` :param service_model: The Botocore service model :rtype: dict, list, or None :return: An appropriate empty value """ response = None operation_model = service_model.operation_model(operation_name) shape = operation_model.output_shape if search_path: # Walk the search path and find the final shape. For example, given # a path of ``foo.bar[0].baz``, we first find the shape for ``foo``, # then the shape for ``bar`` (ignoring the indexing), and finally # the shape for ``baz``. for item in search_path.split('.'): item = item.strip('[0123456789]$') if shape.type_name == 'structure': shape = shape.members[item] elif shape.type_name == 'list': shape = shape.member else: raise NotImplementedError( 'Search path hits shape type {} from {}'.format( shape.type_name, item ) ) # Anything not handled here is set to None if shape.type_name == 'structure': response = {} elif shape.type_name == 'list': response = [] elif shape.type_name == 'map': response = {} return response
[docs]class RawHandler: """ A raw action response handler. This passed through the response dictionary, optionally after performing a JMESPath search if one has been defined for the action. :type search_path: string :param search_path: JMESPath expression to search in the response :rtype: dict :return: Service response """ def __init__(self, search_path): self.search_path = search_path def __call__(self, parent, params, response): """ :type parent: ServiceResource :param parent: The resource instance to which this action is attached. :type params: dict :param params: Request parameters sent to the service. :type response: dict :param response: Low-level operation response. """ # TODO: Remove the '$' check after JMESPath supports it if self.search_path and self.search_path != '$': response = jmespath.search(self.search_path, response) return response
[docs]class ResourceHandler: """ Creates a new resource or list of new resources from the low-level response based on the given response resource definition. :type search_path: string :param search_path: JMESPath expression to search in the response :type factory: ResourceFactory :param factory: The factory that created the resource class to which this action is attached. :type resource_model: :py:class:`~boto3.resources.model.ResponseResource` :param resource_model: Response resource model. :type service_context: :py:class:`~boto3.utils.ServiceContext` :param service_context: Context about the AWS service :type operation_name: string :param operation_name: Name of the underlying service operation, if it exists. :rtype: ServiceResource or list :return: New resource instance(s). """ def __init__( self, search_path, factory, resource_model, service_context, operation_name=None, ): self.search_path = search_path self.factory = factory self.resource_model = resource_model self.operation_name = operation_name self.service_context = service_context def __call__(self, parent, params, response): """ :type parent: ServiceResource :param parent: The resource instance to which this action is attached. :type params: dict :param params: Request parameters sent to the service. :type response: dict :param response: Low-level operation response. """ resource_name = self.resource_model.type json_definition = self.service_context.resource_json_definitions.get( resource_name ) # Load the new resource class that will result from this action. resource_cls = self.factory.load_from_definition( resource_name=resource_name, single_resource_json_definition=json_definition, service_context=self.service_context, ) raw_response = response search_response = None # Anytime a path is defined, it means the response contains the # resource's attributes, so resource_data gets set here. It # eventually ends up in resource.meta.data, which is where # the attribute properties look for data. if self.search_path: search_response = jmespath.search(self.search_path, raw_response) # First, we parse all the identifiers, then create the individual # response resources using them. Any identifiers that are lists # will have one item consumed from the front of the list for each # resource that is instantiated. Items which are not a list will # be set as the same value on each new resource instance. identifiers = dict( build_identifiers( self.resource_model.identifiers, parent, params, raw_response ) ) # If any of the identifiers is a list, then the response is plural plural = [v for v in identifiers.values() if isinstance(v, list)] if plural: response = [] # The number of items in an identifier that is a list will # determine how many resource instances to create. for i in range(len(plural[0])): # Response item data is *only* available if a search path # was given. This prevents accidentally loading unrelated # data that may be in the response. response_item = None if search_response: response_item = search_response[i] response.append( self.handle_response_item( resource_cls, parent, identifiers, response_item ) ) elif all_not_none(identifiers.values()): # All identifiers must always exist, otherwise the resource # cannot be instantiated. response = self.handle_response_item( resource_cls, parent, identifiers, search_response ) else: # The response should be empty, but that may mean an # empty dict, list, or None based on whether we make # a remote service call and what shape it is expected # to return. response = None if self.operation_name is not None: # A remote service call was made, so try and determine # its shape. response = build_empty_response( self.search_path, self.operation_name, self.service_context.service_model, ) return response
[docs] def handle_response_item( self, resource_cls, parent, identifiers, resource_data ): """ Handles the creation of a single response item by setting parameters and creating the appropriate resource instance. :type resource_cls: ServiceResource subclass :param resource_cls: The resource class to instantiate. :type parent: ServiceResource :param parent: The resource instance to which this action is attached. :type identifiers: dict :param identifiers: Map of identifier names to value or values. :type resource_data: dict or None :param resource_data: Data for resource attributes. :rtype: ServiceResource :return: New resource instance. """ kwargs = { 'client': parent.meta.client, } for name, value in identifiers.items(): # If value is a list, then consume the next item if isinstance(value, list): value = value.pop(0) kwargs[name] = value resource = resource_cls(**kwargs) if resource_data is not None: resource.meta.data = resource_data return resource