+
−# Copyright 2009 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.
+
−
+
−"""The Melange Core module.
+
−"""
+
−
+
−__authors__ = [
+
−  '"Sverre Rabbelier" <sverre@rabbelier.nl>',
+
−  '"Lennard de Rijk" <ljvderijk@gmail.com>',
+
−  ]
+
−
+
−
+
−from django.conf.urls import defaults
+
−
+
−import settings
+
−import soc.cache.sidebar
+
−
+
−
+
−class Error(Exception):
+
−  """Error class for the callback module.
+
−  """
+
−
+
−  pass
+
−
+
−
+
−class APIVersionMismatch(Error):
+
−  """Error raised when API version mismatches.
+
−  """
+
−
+
−  MISMATCH_MSG_FMT = "API mismatch, expected '%d', got '%d'."
+
−
+
−  def __init__(self, expected, actual):
+
−    """Instantiates a new exception with a customized message.
+
−    """
+
−
+
−    msg = self.MISMATCH_MSG_FMT % (expected, actual)
+
−    super(APIVersionMismatch, self).__init__(msg)
+
−
+
−
+
−class MissingService(Error):
+
−  """Error raised when a required service is missing.
+
−  """
+
−
+
−  MISSING_SERVICE_FMT = "Required service '%s' is not registered, known: %s"
+
−
+
−  def __init__(self, service, services):
+
−    """Instantiates a new exception with a customized message.
+
−    """
+
−
+
−    msg = self.MISSING_SERVICE_FMT % (service, services)
+
−    super(MissingService, self).__init__(msg)
+
−
+
−
+
−class MissingCapability(Error):
+
−  """Error raised when a required capability is missing.
+
−  """
+
−
+
−  MISSING_CAPABILITY_FMT = "Required capability '%s' " + \
+
−      "is not registered, known: %s"
+
−
+
−  def __init__(self, capability, capabilities):
+
−    """Instantiates a new exception with a customized message.
+
−    """
+
−
+
−    msg = self.MISSING_CAPABILITY_FMT % (capability, capabilities)
+
−    super(MissingCapability, self).__init__(msg)
+
−
+
−
+
−class NonUniqueService(Error):
+
−  """Error raised when a required service is missing.
+
−  """
+
−
+
−  NON_UNIQUE_SERVICE_FMT = "Unique service '%s' called a 2nd time, known: %s."
+
−
+
−  def __init__(self, service, services):
+
−    """Instantiates a new exception with a customized message.
+
−    """
+
−
+
−    msg = self.NON_UNIQUE_SERVICE_FMT % (service, services)
+
−    super(NonUniqueService, self).__init__(msg)
+
−
+
−
+
−class Core(object):
+
−  """The core handler that controls the Melange API.
+
−  """
+
−
+
−  def __init__(self):
+
−    """Creates a new instance of the Core.
+
−    """
+
−    
+
−    # pylint: disable-msg=C0103
+
−    self.API_VERSION = 1
+
−
+
−    self.registered_callbacks = []
+
−    self.capabilities = []
+
−    self.services = []
+
−
+
−    self.sitemap = []
+
−    self.sidebar = []
+
−
+
−  ##
+
−  ## internal
+
−  ##
+
−
+
−  def getService(self, callback, service):
+
−    """Retrieves the specified service from the callback if supported.
+
−
+
−    Args:
+
−     callback: the callback to retrieve the capability from
+
−     service: the service to retrieve
+
−    """
+
−
+
−    if not hasattr(callback, service):
+
−      return False
+
−
+
−    func = getattr(callback, service)
+
−
+
−    if not callable(func):
+
−      return False
+
−
+
−    return func
+
−
+
−  ##
+
−  ## Core code
+
−  ##
+
−
+
−  def getPatterns(self):
+
−    """Returns the Django patterns for this site.
+
−    """
+
−
+
−    self.callService('registerWithSitemap', True)
+
−    return defaults.patterns(None, *self.sitemap)
+
−
+
−  @soc.cache.sidebar.cache
+
−  def getSidebar(self, id, user):
+
−    """Constructs a sidebar for the current user.
+
−    """
+
−
+
−    self.callService('registerWithSidebar', True)
+
−
+
−    sidebar = []
+
−
+
−    for i in self.sidebar:
+
−      menus = i(id, user)
+
−
+
−      for menu in (menus if menus else []):
+
−        sidebar.append(menu)
+
−
+
−    return sorted(sidebar, key=lambda x: x.get('group'))
+
−
+
−  def callService(self, service, unique, *args, **kwargs):
+
−    """Calls the specified service on all callbacks.
+
−    """
+
−
+
−    if unique and (service in self.services):
+
−      return
+
−
+
−    results = []
+
−
+
−    for callback in self.registered_callbacks:
+
−      func = self.getService(callback, service)
+
−      if not func:
+
−        continue
+
−
+
−      result = func(*args, **kwargs)
+
−      results.append(result)
+
−
+
−    self.services.append(service)
+
−    return results
+
−
+
−  def registerModuleCallbacks(self):
+
−    """Retrieves all callbacks for the modules of this site.
+
−
+
−    Callbacks for modules without a version number or the wrong API_VERSION
+
−    number are dropped.  They won't be called.
+
−    """
+
−
+
−    fmt = settings.MODULE_FMT
+
−    modules = ['soc_core'] + settings.MODULES
+
−    modules = [__import__(fmt % i, fromlist=['']) for i in modules]
+
−
+
−    for callback_class in [i.Callback for i in modules]:
+
−      if callback_class.API_VERSION != self.API_VERSION:
+
−        raise APIVersionMismatch(self.API_VERSION,
+
−                                 callback_class.API_VERSION)
+
−
+
−
+
−      callback = callback_class(self)
+
−      self.registered_callbacks.append(callback)
+
−
+
−    return True
+
−
+
−  ##
+
−  ## Module code
+
−  ##
+
−
+
−  def registerCapability(self, capability):
+
−    """Registers the specified capability.
+
−    """
+
−
+
−    self.capabilities.append(capability)
+
−
+
−  def requireCapability(self, capability):
+
−    """Requires that the specified capability is present.
+
−    """
+
−
+
−    if capability in self.capabilities:
+
−      return True
+
−
+
−    raise MissingCapability(capability, self.capabilities)
+
−
+
−  def requireService(self, service):
+
−    """Requires that the specified service has been called.
+
−    """
+
−
+
−    if service in self.services:
+
−      return True
+
−
+
−    raise MissingService(service, self.services)
+
−
+
−  def requireUniqueService(self, service):
+
−    """Requires that the specified service is called exactly once.
+
−    """
+
−
+
−    if service not in self.services:
+
−      return True
+
−
+
−    raise NonUniqueService(service, self.services)
+
−
+
−  def registerSitemapEntry(self, entries):
+
−    """Registers the specified entries with the sitemap.
+
−    """
+
−
+
−    self.sitemap.extend(entries)
+
−
+
−  def registerSidebarEntry(self, entry):
+
−    """Registers the specified entry with the sidebar.
+
−    """
+
−
+
−    self.sidebar.append(entry)