mediagoblin/submit/lib.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU Affero General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 import logging
  18 import uuid
  19 from werkzeug.utils import secure_filename
  20 from werkzeug.datastructures import FileStorage
  21
  22 from mediagoblin.processing import mark_entry_failed
  23 from mediagoblin.processing.task import process_media
  24
  25
  26 _log = logging.getLogger(__name__)
  27
  28
  29 def check_file_field(request, field_name):
  30     """Check if a file field meets minimal criteria"""
  31     retval = (field_name in request.files
  32               and isinstance(request.files[field_name], FileStorage)
  33               and request.files[field_name].stream)
  34     if not retval:
  35         _log.debug("Form did not contain proper file field %s", field_name)
  36     return retval
  37
  38
  39 def prepare_queue_task(app, entry, filename):
  40     """
  41     Prepare a MediaEntry for the processing queue and get a queue file
  42     """
  43     # We generate this ourselves so we know what the taks id is for
  44     # retrieval later.
  45
  46     # (If we got it off the task's auto-generation, there'd be
  47     # a risk of a race condition when we'd save after sending
  48     # off the task)
  49     task_id = unicode(uuid.uuid4())
  50     entry.queued_task_id = task_id
  51
  52     # Now store generate the queueing related filename
  53     queue_filepath = app.queue_store.get_unique_filepath(
  54         ['media_entries',
  55          task_id,
  56          secure_filename(filename)])
  57
  58     # queue appropriately
  59     queue_file = app.queue_store.get_file(
  60         queue_filepath, 'wb')
  61
  62     # Add queued filename to the entry
  63     entry.queued_media_file = queue_filepath
  64
  65     return queue_file
  66
  67
  68 def run_process_media(entry, feed_url=None):
  69     """Process the media asynchronously
  70
  71     :param entry: MediaEntry() instance to be processed.
  72     :param feed_url: A string indicating the feed_url that the PuSH servers
  73         should be notified of. This will be sth like: `request.urlgen(
  74             'mediagoblin.user_pages.atom_feed',qualified=True,
  75             user=request.user.username)`"""
  76     try:
  77         process_media.apply_async(
  78             [entry.id, feed_url], {},
  79             task_id=entry.queued_task_id)
  80     except BaseException as exc:
  81         # The purpose of this section is because when running in "lazy"
  82         # or always-eager-with-exceptions-propagated celery mode that
  83         # the failure handling won't happen on Celery end.  Since we
  84         # expect a lot of users to run things in this way we have to
  85         # capture stuff here.
  86         #
  87         # ... not completely the diaper pattern because the
  88         # exception is re-raised :)
  89         mark_entry_failed(entry.id, exc)
  90         # re-raise the exception
  91         raise