mediagoblin/mediagoblin/processing.py
2012-01-04 11:57:39 +01:00

144 lines
4.7 KiB
Python

# GNU MediaGoblin -- federated, autonomous media hosting
# Copyright (C) 2011 MediaGoblin contributors. See AUTHORS.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
from celery.task import Task
from mediagoblin.db.util import ObjectId
from mediagoblin import mg_globals as mgg
from mediagoblin.tools.translate import lazy_pass_to_ugettext as _
from mediagoblin.media_types import get_media_manager
THUMB_SIZE = 180, 180
MEDIUM_SIZE = 640, 640
def create_pub_filepath(entry, filename):
return mgg.public_store.get_unique_filepath(
['media_entries',
unicode(entry._id),
filename])
################################
# Media processing initial steps
################################
class ProcessMedia(Task):
"""
DEPRECATED -- This now resides in the individual media plugins
Pass this entry off for processing.
"""
def run(self, media_id):
"""
Pass the media entry off to the appropriate processing function
(for now just process_image...)
"""
entry = mgg.database.MediaEntry.one(
{'_id': ObjectId(media_id)})
# Try to process, and handle expected errors.
try:
#__import__(entry.media_type)
manager = get_media_manager(entry.media_type)
manager['processor'](entry)
except BaseProcessingFail, exc:
mark_entry_failed(entry._id, exc)
return
except ImportError, exc:
mark_entry_failed(entry[u'_id'], exc)
entry.state = u'processed'
entry.save()
def on_failure(self, exc, task_id, args, kwargs, einfo):
"""
If the processing failed we should mark that in the database.
Assuming that the exception raised is a subclass of
BaseProcessingFail, we can use that to get more information
about the failure and store that for conveying information to
users about the failure, etc.
"""
entry_id = args[0]
mark_entry_failed(entry_id, exc)
def mark_entry_failed(entry_id, exc):
"""
Mark a media entry as having failed in its conversion.
Uses the exception that was raised to mark more information. If
the exception is a derivative of BaseProcessingFail then we can
store extra information that can be useful for users telling them
why their media failed to process.
Args:
- entry_id: The id of the media entry
"""
# Was this a BaseProcessingFail? In other words, was this a
# type of error that we know how to handle?
if isinstance(exc, BaseProcessingFail):
# Looks like yes, so record information about that failure and any
# metadata the user might have supplied.
mgg.database['media_entries'].update(
{'_id': entry_id},
{'$set': {u'state': u'failed',
u'fail_error': exc.exception_path,
u'fail_metadata': exc.metadata}})
else:
# Looks like no, so just mark it as failed and don't record a
# failure_error (we'll assume it wasn't handled) and don't record
# metadata (in fact overwrite it if somehow it had previous info
# here)
mgg.database['media_entries'].update(
{'_id': entry_id},
{'$set': {u'state': u'failed',
u'fail_error': None,
u'fail_metadata': {}}})
class BaseProcessingFail(Exception):
"""
Base exception that all other processing failure messages should
subclass from.
You shouldn't call this itself; instead you should subclass it
and provid the exception_path and general_message applicable to
this error.
"""
general_message = u''
@property
def exception_path(self):
return u"%s:%s" % (
self.__class__.__module__, self.__class__.__name__)
def __init__(self, **metadata):
self.metadata = metadata or {}
class BadMediaFail(BaseProcessingFail):
"""
Error that should be raised when an inappropriate file was given
for the media type specified.
"""
general_message = _(u'Invalid file given for media type.')