Source code for boto3.resources.params

# Copyright 2014, 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
# or in the "license" file accompanying this file. This file is
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.

import re

import jmespath
from botocore import xform_name

from ..exceptions import ResourceLoadException

INDEX_RE = re.compile(r'\[(.*)\]$')

[docs]def get_data_member(parent, path): """ Get a data member from a parent using a JMESPath search query, loading the parent if required. If the parent cannot be loaded and no data is present then an exception is raised. :type parent: ServiceResource :param parent: The resource instance to which contains data we are interested in. :type path: string :param path: The JMESPath expression to query :raises ResourceLoadException: When no data is present and the resource cannot be loaded. :returns: The queried data or ``None``. """ # Ensure the parent has its data loaded, if possible. if is None: if hasattr(parent, 'load'): parent.load() else: raise ResourceLoadException( '{0} has no load method!'.format(parent.__class__.__name__)) return,
[docs]def create_request_parameters(parent, request_model, params=None, index=None): """ Handle request parameters that can be filled in from identifiers, resource data members or constants. By passing ``params``, you can invoke this method multiple times and build up a parameter dict over time, which is particularly useful for reverse JMESPath expressions that append to lists. :type parent: ServiceResource :param parent: The resource instance to which this action is attached. :type request_model: :py:class:`~boto3.resources.model.Request` :param request_model: The action request model. :type params: dict :param params: If set, then add to this existing dict. It is both edited in-place and returned. :type index: int :param index: The position of an item within a list :rtype: dict :return: Pre-filled parameters to be sent to the request operation. """ if params is None: params = {} for param in request_model.params: source = param.source target = if source == 'identifier': # Resource identifier, e.g. queue.url value = getattr(parent, xform_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, param.path) elif source in ['string', 'integer', 'boolean']: # These are hard-coded values in the definition value = param.value elif source == 'input': # This is provided by the user, so ignore it here continue else: raise NotImplementedError( 'Unsupported source type: {0}'.format(source)) build_param_structure(params, target, value, index) return params
[docs]def build_param_structure(params, target, value, index=None): """ This method provides a basic reverse JMESPath implementation that lets you go from a JMESPath-like string to a possibly deeply nested object. The ``params`` are mutated in-place, so subsequent calls can modify the same element by its index. >>> build_param_structure(params, 'test[0]', 1) >>> print(params) {'test': [1]} >>> build_param_structure(params, '[0].baz', 'hello world') >>> print(params) {'test': [1], 'foo': {'bar': [{'baz': 'hello, world'}]}} """ pos = params parts = target.split('.') # First, split into parts like 'foo', 'bar[0]', 'baz' and process # each piece. It can either be a list or a dict, depending on if # an index like `[0]` is present. We detect this via a regular # expression, and keep track of where we are in params via the # pos variable, walking down to the last item. Once there, we # set the value. for i, part in enumerate(parts): # Is it indexing an array? result = if result: if if == '*': part = part[:-3] else: # We have an explicit index index = int( part = part[:-len(str(index) + '[]')] else: # Index will be set after we know the proper part # name and that it's a list instance. index = None part = part[:-2] if part not in pos or not isinstance(pos[part], list): pos[part] = [] # This means we should append, e.g. 'foo[]' if index is None: index = len(pos[part]) while len(pos[part]) <= index: # Assume it's a dict until we set the final value below pos[part].append({}) # Last item? Set the value, otherwise set the new position if i == len(parts) - 1: pos[part][index] = value else: # The new pos is the *item* in the array, not the array! pos = pos[part][index] else: if part not in pos: pos[part] = {} # Last item? Set the value, otherwise set the new position if i == len(parts) - 1: pos[part] = value else: pos = pos[part]