# GNU MediaGoblin -- federated, autonomous media hosting
-# Copyright (C) 2011 MediaGoblin contributors. See AUTHORS.
+# Copyright (C) 2011, 2012 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
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import os
-import sys
+import logging
+import shutil
+import tempfile
-from mediagoblin import mg_globals
+from mediagoblin.tools.pluginapi import hook_handle
from mediagoblin.tools.translate import lazy_pass_to_ugettext as _
+_log = logging.getLogger(__name__)
+
class FileTypeNotSupported(Exception):
pass
-class InvalidFileType(Exception):
+
+class TypeNotFound(FileTypeNotSupported):
+ '''Raised if no mediagoblin plugin supporting this file type was found'''
pass
-def get_media_types():
- """
- Generator, yields the available media types
- """
- for media_type in mg_globals.app_config['media_types']:
- yield media_type
+class MissingComponents(FileTypeNotSupported):
+ '''Raised if plugin found, but it can't process the file for some reason'''
+ pass
+
+class MediaManagerBase(object):
+ "Base class for all media managers"
+
+ # Please override in actual media managers
+ media_fetch_order = None
+
+ @staticmethod
+ def sniff_handler(*args, **kwargs):
+ return False
-def get_media_managers():
+ def __init__(self, entry):
+ self.entry = entry
+
+ def __getitem__(self, i):
+ return getattr(self, i)
+
+ def __contains__(self, i):
+ return hasattr(self, i)
+
+
+def sniff_media_contents(media_file, filename):
'''
- Generator, yields all enabled media managers
+ Check media contents using 'expensive' scanning. For example, for video it
+ is checking the contents using gstreamer
+ :param media_file: file-like object with 'name' attribute
+ :param filename: expected filename of the media
'''
- for media_type in get_media_types():
- __import__(media_type)
-
- yield media_type, sys.modules[media_type].MEDIA_MANAGER
-
+ media_type = hook_handle('sniff_handler', media_file, filename)
+ if media_type:
+ _log.info('{0} accepts the file'.format(media_type))
+ return media_type, hook_handle(('media_manager', media_type))
+ else:
+ _log.debug('{0} did not accept the file'.format(media_type))
+ raise FileTypeNotSupported(
+ # TODO: Provide information on which file types are supported
+ _(u'Sorry, I don\'t support that file type :('))
-def get_media_manager(_media_type):
+def get_media_type_and_manager(filename):
'''
- Get the MEDIA_MANAGER based on a media type string
+ Try to find the media type based on the file name, extension
+ specifically. This is used as a speedup, the sniffing functionality
+ then falls back on more in-depth bitsniffing of the source file.
- Example::
- get_media_type('mediagoblin.media_types.image')
+ This hook is deprecated, 'type_match_handler' should be used instead
'''
- if not _media_type:
- return False
+ if os.path.basename(filename).find('.') > 0:
+ # Get the file extension
+ ext = os.path.splitext(filename)[1].lower()
- for media_type, manager in get_media_managers():
- if media_type in _media_type:
- return manager
+ # Omit the dot from the extension and match it against
+ # the media manager
+ if hook_handle('get_media_type_and_manager', ext[1:]):
+ return hook_handle('get_media_type_and_manager', ext[1:])
+ else:
+ _log.info('File {0} has no file extension, let\'s hope the sniffers get it.'.format(
+ filename))
- # Nope? Then raise an error
- raise FileTypeNotSupported(
- "MediaManager not in enabled types. Check media_types in config?")
+ raise TypeNotFound(
+ _(u'Sorry, I don\'t support that file type :('))
+def type_match_handler(media_file, filename):
+ '''Check media file by name and then by content
-def get_media_type_and_manager(filename):
- '''
- Get the media type and manager based on a filename
+ Try to find the media type based on the file name, extension
+ specifically. After that, if media type is one of supported ones, check the
+ contents of the file
'''
- for media_type, manager in get_media_managers():
- if filename.find('.') > 0:
- # Get the file extension
- ext = os.path.splitext(filename)[1].lower()
- else:
- raise InvalidFileType(
- _('Could not find any file extension in "{filename}"').format(
- filename=filename))
+ if os.path.basename(filename).find('.') > 0:
+ # Get the file extension
+ ext = os.path.splitext(filename)[1].lower()
# Omit the dot from the extension and match it against
# the media manager
- if ext[1:] in manager['accepted_extensions']:
- return media_type, manager
+ hook_result = hook_handle('type_match_handler', ext[1:])
+ if hook_result:
+ _log.info('Info about file found, checking further')
+ MEDIA_TYPE, Manager, sniffer = hook_result
+ if not sniffer:
+ _log.debug('sniffer is None, plugin trusts the extension')
+ return MEDIA_TYPE, Manager
+ _log.info('checking the contents with sniffer')
+ try:
+ sniffer(media_file)
+ _log.info('checked, found')
+ return MEDIA_TYPE, Manager
+ except Exception as e:
+ _log.info('sniffer says it will not accept the file')
+ _log.debug(e)
+ raise
+ else:
+ _log.info('No plugins handled extension {0}'.format(ext))
+ else:
+ _log.info('File {0} has no known file extension, let\'s hope '
+ 'the sniffers get it.'.format(filename))
+ raise TypeNotFound(_(u'Sorry, I don\'t support that file type :('))
+
+
+def sniff_media(media_file, filename):
+ '''
+ Iterate through the enabled media types and find those suited
+ for a certain file.
+ '''
+ # copy the contents to a .name-enabled temporary file for further checks
+ # TODO: there are cases when copying is not required
+ tmp_media_file = tempfile.NamedTemporaryFile()
+ shutil.copyfileobj(media_file, tmp_media_file)
+ media_file.seek(0)
+ try:
+ return type_match_handler(tmp_media_file, filename)
+ except TypeNotFound as e:
+ _log.info('No plugins using two-step checking found')
+
+ # keep trying, using old `get_media_type_and_manager`
+ try:
+ return get_media_type_and_manager(filename)
+ except TypeNotFound as e:
+ # again, no luck. Do it expensive way
+ _log.info('No media handler found by file extension')
+ _log.info('Doing it the expensive way...')
+ return sniff_media_contents(tmp_media_file, filename)
+
projects / mediagoblin.git / blobdiff