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−#!/usr/bin/python2.5
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−#
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−# Copyright 2009 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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−"""Decorators for the Task API.
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−"""
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−
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−__authors__ = [
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−  '"Daniel Hans" <daniel.m.hans@gmail.com>',
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−  '"Lennard de Rijk" <ljvderijk@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.ext import db
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−
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−from soc.tasks import responses as task_responses
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−
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−
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−def task(func):
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−  """Task decorator wrapper method
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−  """
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−
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−  @wraps(func)
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−  def wrapper(request, *args, **kwargs):
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−    """Decorator wrapper method
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−    """
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−
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−    try:
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−      return func(request, *args, **kwargs)
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−    except task_responses.FatalTaskError, error:
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−      logging.exception(error)
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−      return task_responses.terminateTask()
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−    except Exception, exception:
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−      logging.exception(exception)
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−      return task_responses.repeatTask()
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−
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−  return wrapper
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−
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−
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−def iterative_task(logic, **task_default):
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−  """Iterative wrapper method
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−
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−  Args:
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−    logic: the Logic instance to get entities for
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−    task_default: keyword arguments which can contain the following options:
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−      fields: dictionary to filter the entities on
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−      start_key: the default key where to start this iterative task
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−  """
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−
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−  def wrapper(func):
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−    def iterative_wrapped(request, *args, **kwargs):
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−      """Decorator wrapper method
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−
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−      Args:
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−        request: Django HTTP Request object
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−
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−      request.POST usage:
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−        fields: a JSON dict for the properties that the entities should have.
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−          This updates values from the task_default entry.
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−        start_key: the key of the next entity to fetch
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−
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−      Returns:
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−        Standard HTTP Django response
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−      """
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−
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−      post_dict = request.POST
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−
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−      fields = task_default.get('fields', {})
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−      if 'fields' in post_dict:
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−        fields.update(simplejson.loads(post_dict['fields']))
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−
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−      start_key = task_default.get('start_key', None)
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−      if 'start_key' in post_dict:
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−        # get the key where to start this iteration
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−        start_key = post_dict['start_key']
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−      if start_key:
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−        start_key = db.Key(start_key)
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−
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−      # get the entities for this iteration
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−      entities, next_start_key = logic.getBatchOfData(filter=fields,
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−                                                      start_key=start_key)
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−
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−      # copy the post_dict so that the wrapped function can edit what it needs
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−      context = post_dict.copy()
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−
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−      try:
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−        func(request, entities=entities, context=context, *args, **kwargs)
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−      except task_responses.FatalTaskError, error:
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−        logging.error(error)
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−        return task_responses.terminateTask()
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−      except Exception, exception:
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−        logging.error(exception)
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−        return task_responses.repeatTask()
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−
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−      if next_start_key:
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−        # set the key to use for the next iteration
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−        context.update({'start_key': next_start_key})
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−
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−        task_responses.startTask(url=request.path, context=context)
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−
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−      return task_responses.terminateTask()
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−
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−    return iterative_wrapped
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−  return wrapper