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−#!/usr/bin/python2.5
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−#
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−# Copyright 2008 the Melange authors.
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−#
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−# Licensed under the Apache License, Version 2.0 (the "License");
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−# you may not use this file except in compliance with the License.
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−# You may obtain a copy of the License at
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−#
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−#   http://www.apache.org/licenses/LICENSE-2.0
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−#
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−# Unless required by applicable law or agreed to in writing, software
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−# distributed under the License is distributed on an "AS IS" BASIS,
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−# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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−# See the License for the specific language governing permissions and
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−# limitations under the License.
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−
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−"""Views decorators.
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−"""
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−
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−__authors__ = [
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−  '"Pawel Solyga" <pawel.solyga@gmail.com>',
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−  ]
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−
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−
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−import logging
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−
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−from functools import wraps
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−
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−from google.appengine.runtime import DeadlineExceededError
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−
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−from django import http
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−
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−from soc.logic import dicts
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−
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−
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−class Error(Exception):
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−  pass
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−
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−
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−def view(func):
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−  """Decorator that insists that exceptions are handled by view.
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−  """
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−  @wraps(func)
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−  def view_wrapper(*args, **kwds):
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−    try:
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−      return func(*args, **kwds)
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−    except DeadlineExceededError:
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−      logging.exception('DeadlineExceededError')
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−      return http.HttpResponse('DeadlineExceededError')
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−    except MemoryError:
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−      logging.exception('MemoryError')
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−      return http.HttpResponse('MemoryError')
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−    except AssertionError:
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−      logging.exception('AssertionError')
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−      return http.HttpResponse('AssertionError')
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−
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−  return view_wrapper
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−
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−
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−def merge_params(func):
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−  """Decorator that merges 'params' with self._params.
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−  """
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−
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−  @wraps(func)
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−  def wrapper(self, *args, **kwargs):
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−    params = kwargs.get('params', {})
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−    kwargs['params'] = dicts.merge(params, self._params)
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−    return func(self, *args, **kwargs)
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−
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−  return wrapper
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−
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−
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−def check_access(func):
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−  """This decorator does access checks for the specified view method.
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−
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−  The rights dictionary is extracted from 'params', or, if either 'params' or
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−  'rights' do not exist, from self._params['rights'].
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−  """
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−
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−  # Do not pollute helper.decorators with access specific imports
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−  from soc.views import out_of_band
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−  from soc.views import helper
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−  from soc.views.helper import access
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−
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−  @wraps(func)
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−  def wrapper(self, request, access_type, *args, **kwargs):
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−    params = kwargs.get('params', {})
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−
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−    # Try to extract rights
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−    if 'rights' in params:
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−      rights = params['rights']
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−    else:
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−      rights = self._params['rights']
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−
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−    # Do the access check dance
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−    try:
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−      access.checkAccess(access_type, request, rights, args, kwargs)
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−    except out_of_band.Error, error:
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−      return helper.responses.errorResponse(error, request)
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−    return func(self, request, access_type, *args, **kwargs)
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−
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−  return wrapper