text: # -*- coding: utf-8 -*-
  #
  # Copyright 2012 OpenStack LLC.
  # 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. You may obtain
  #    a copy of the License at
  #
  #         http://www.apache.org/licenses/LICENSE-2.0
  #
  #    Unless required by applicable law or agreed to in writing, software
  #    distributed under the License 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.
  
  """
  Base utilities to build API operation managers and objects on top of.
  """
  
  import copy
  from urllib import parse as urlparse
  
  from magnumclient.common.apiclient import base
  
  
  def getid(obj):
      """Wrapper to get  object's ID.
  
      Abstracts the common pattern of allowing both an object or an
      object's ID (UUID) as a parameter when dealing with relationships.
      """
      return getattr(obj, 'id', obj)
  
  
  class Manager(object):
      """Provides  CRUD operations with a particular API."""
      resource_class = None
  
      def __init__(self, api):
          self.api = api
  
      def _create(self, url, body):
          resp, body = self.api.json_request('POST', url, body=body)
          if body:
              return self.resource_class(self, body)
  
      def _format_body_data(self, body, response_key):
          if response_key:
              try:
                  data = body[response_key]
              except KeyError:
                  return []
          else:
              data = body
  
          if not isinstance(data, list):
              data = [data]
  
          return data
  
      def _list_pagination(self, url, response_key=None, obj_class=None,
                           limit=None):
          """Retrieve a list of items.
  
          The Magnum API is configured to return a maximum number of
          items per request, (FIXME: see Magnum's api.max_limit option). This
          iterates over the 'next' link (pagination) in the responses,
          to get the number of items specified by 'limit'. If 'limit'
          is None this function will continue pagination until there are
          no more values to be returned.
  
          :param url: a partial URL, e.g. '/nodes'
          :param response_key: the key to be looked up in response
              dictionary, e.g. 'nodes'
          :param obj_class: class for constructing the returned objects.
          :param limit: maximum number of items to return. If None returns
              everything.
  
          """
          if obj_class is None:
              obj_class = self.resource_class
  
          if limit is not None:
              limit = int(limit)
  
          object_list = []
          object_count = 0
          limit_reached = False
          while url:
              resp, body = self.api.json_request('GET', url)
              data = self._format_body_data(body, response_key)
              for obj in data:
                  object_list.append(obj_class(self, obj, loaded=True))
                  object_count += 1
                  if limit and object_count >= limit:
                      # break the for loop
                      limit_reached = True
                      break
  
              # break the while loop and return
              if limit_reached:
                  break
  
              url = body.get('next')
              if url:
                  # NOTE(lucasagomes): We need to edit the URL to remove
                  # the scheme and netloc
                  url_parts = list(urlparse.urlparse(url))
                  url_parts[0] = url_parts[1] = ''
                  url = urlparse.urlunparse(url_parts)
  
          return object_list
  
      def _list(self, url, response_key=None, obj_class=None, body=None):
          resp, body = self.api.json_request('GET', url)
  
          if obj_class is None:
              obj_class = self.resource_class
  
          data = self._format_body_data(body, response_key)
          return [obj_class(self, res, loaded=True) for res in data if res]
  
      def _update(self, url, body=None, method='PATCH', response_key=None):
          if body:
              resp, resp_body = self.api.json_request(method, url, body=body)
          else:
              resp, resp_body = self.api.raw_request(method, url)
          # PATCH/PUT requests may not return a body
          if resp_body:
              return self.resource_class(self, resp_body)
  
      def _delete(self, url):
          self.api.raw_request('DELETE', url)
  
  
  class Resource(base.Resource):
      """Represents a particular instance of an object (tenant, user, etc).
  
      This is pretty much just a bag for attributes.
      """
  
      def to_dict(self):
          return copy.deepcopy(self._info)
  