app/soc/logic/models/site.py
author Daniel Hans <Daniel.M.Hans@gmail.com>
Fri, 07 Aug 2009 01:27:24 +0200
changeset 2736 8f3935f0f4ba
parent 2072 eb4565a8e5b4
permissions -rw-r--r--
Argument store added to updateEntityProperties. This argument determines if an entity should be stored in the data model after its properties are updated. It may be useful, for example, along with tasks (Task Queue API). One may want to make some modifications to an entity during execution of a task, but the developer is sure that at least one new task, which also wants to modify the entity, will be queued, so he or she can just update the entity without saving the changes to the data model, set the entity in memcache and the following task (which is to be executed very shortly) is to retrive the current entity from the memcache (without any expensive calls to the actual data model).

#!/usr/bin/python2.5
#
# Copyright 2008 the Melange authors.
#
# 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.

"""Site (Model) query functions.
"""

__authors__ = [
  '"Sverre Rabbelier" <sverre@rabbelier.nl>',
  ]


from soc.logic.models import presence_with_tos

import soc.models.presence_with_tos
import soc.models.site


class Logic(presence_with_tos.Logic):
  """Logic methods for the Site model.
  """

  DEF_SITE_LINK_ID = 'site'

  def __init__(self, model=soc.models.site.Site,
               base_model=soc.models.presence_with_tos.PresenceWithToS):
    """Defines the name, key_name and model for this entity.
    """

    super(Logic, self).__init__(model=model, base_model=base_model)

  def getKeyValuesFromEntity(self, entity):
    """Returns the key values for the site settings.

    The Site entity is a singleton, so this method returns 
    a hard-coded link_id.

    Args:
      entity: unused
    """

    return [self.DEF_SITE_LINK_ID]

  def getKeyValuesFromFields(self, fields):
    """Extracts the key values from a dict and returns them.

    The Site entity is a singleton, so this method returns 
    a hard-coded link_id.

    Args:
      fields: unused
    """

    return [self.DEF_SITE_LINK_ID]

  def getKeyFieldNames(self):
    """Returns an array with the names of the Key Fields.

    The Site entity is an unscoped singleton, it's key fields consist
    of just the link_id.
    """

    return ['link_id']

  def getSingleton(self):
    """Return singleton Site settings entity, since there is always only one.
    """

    fields = {
        'link_id': self.DEF_SITE_LINK_ID,
        }

    key_name = self.getKeyNameFromFields(fields)
    singleton = self.getFromKeyName(key_name)

    # if there is no site singleton yet, create it
    if not singleton:
      singleton = self.updateOrCreateFromKeyName(fields, key_name)

    return singleton

logic = Logic()