aboutsummaryrefslogtreecommitdiffstats
path: root/mediagoblin/processing/__init__.py
blob: e2bc1a130f28952c45b2214795b2aee729ed6fe1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
# GNU MediaGoblin -- federated, autonomous media hosting
# 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
# 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/>.

import logging
import os

from mediagoblin.db.util import atomic_update
from mediagoblin import mg_globals as mgg

from mediagoblin.tools.translate import lazy_pass_to_ugettext as _

_log = logging.getLogger(__name__)


class ProgressCallback(object):
    def __init__(self, entry):
        self.entry = entry

    def __call__(self, progress):
        if progress:
            self.entry.transcoding_progress = progress
            self.entry.save()


def create_pub_filepath(entry, filename):
    return mgg.public_store.get_unique_filepath(
            ['media_entries',
             unicode(entry.id),
             filename])


class FilenameBuilder(object):
    """Easily slice and dice filenames.

    Initialize this class with an original file path, then use the fill()
    method to create new filenames based on the original.

    """
    MAX_FILENAME_LENGTH = 255  # VFAT's maximum filename length

    def __init__(self, path):
        """Initialize a builder from an original file path."""
        self.dirpath, self.basename = os.path.split(path)
        self.basename, self.ext = os.path.splitext(self.basename)
        self.ext = self.ext.lower()

    def fill(self, fmtstr):
        """Build a new filename based on the original.

        The fmtstr argument can include the following:
        {basename} -- the original basename, with the extension removed
        {ext} -- the original extension, always lowercase

        If necessary, {basename} will be truncated so the filename does not
        exceed this class' MAX_FILENAME_LENGTH in length.

        """
        basename_len = (self.MAX_FILENAME_LENGTH -
                        len(fmtstr.format(basename='', ext=self.ext)))
        return fmtstr.format(basename=self.basename[:basename_len],
                             ext=self.ext)


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.
        atomic_update(mgg.database.MediaEntry,
            {'id': entry_id},
            {u'state': u'failed',
             u'fail_error': unicode(exc.exception_path),
             u'fail_metadata': exc.metadata})
    else:
        _log.warn("No idea what happened here, but it failed: %r", exc)
        # 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)
        atomic_update(mgg.database.MediaEntry,
            {'id': entry_id},
            {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.')