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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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−"""Common validation helper functions.
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−"""
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−
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−__authors__ = [
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−  '"Lennard de Rijk" <ljvderijk@gmail.com>',
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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 feedparser
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−
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−from google.appengine.api import urlfetch
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−from google.appengine.api import urlfetch_errors
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−
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−from soc.models import linkable
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−
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−
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−def isFeedURLValid(feed_url=None):
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−  """Returns True if provided url is valid ATOM or RSS.
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−
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−  Args:
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−    feed_url: ATOM or RSS feed url
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−  """
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−
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−  # a missing or empty feed url is never valid
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−  if not feed_url:
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−    return False
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−
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−  try:
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−    result = urlfetch.fetch(feed_url)
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−  except urlfetch_errors.Error:
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−    return False
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−
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−  # 200 is the status code for 'all ok'
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−  if result.status_code != 200:
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−    return False
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−
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−  parsed_feed = feedparser.parse(result.content)
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−
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−  # version is always present if the feed is valid
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−  if not parsed_feed.version:
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−    return False
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−
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−  # TODO: isn't this check redunant?
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−  if parsed_feed.version == '':
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−    return False
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−
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−  return True
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−
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−
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−def isLinkIdFormatValid(link_id):
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−  """Returns True if link_id is in a valid format.
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−
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−  Args:
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−    link_id: link ID used in URLs for identification
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−  """
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−  if linkable.LINK_ID_REGEX.match(link_id):
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−    return True
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−  return False
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−
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−
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−def isScopePathFormatValid(scope_path):
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−  """Returns True if scope_path is in a valid format.
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−  
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−  Args:
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−    scope_path: scope path prepended to link ID
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−      used for identification.
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−  """
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−   
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−  if linkable.SCOPE_PATH_REGEX.match(scope_path):
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−    return True
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−  
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−  return False