Rename music files in a directory according to tags

music-renamer.py

#!/usr/bin/env python2
# coding: utf-8
#
# Copyright (c) 2015, tobbez
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#

from __future__ import division, print_function, unicode_literals

import mutagen
import os
import re
import sys


def sanitize_path_component(name):
    """Replace characters that are not allowed in filenames on common operating
    systems with underscores"""
    return re.sub(u'''['/<>:"\\|\\\\?\\*]''', u'_', name)


class MusicRenamer(object):
    filename_re = '\\.(flac|mp3)$'

    def run(self, args):
        """Entry point for the application"""
        args = [arg.decode('utf-8') for arg in args]
        if len(args) < 3 or '-h' in args or '--help' in args:
            self.usage(args[0])
            return

        fmt = args[1]

        for directory in args[2:]:
            self.handle_dir(directory, fmt)

    def usage(self, appname):
        """Print usage instructions"""
        print('Usage: {} <FORMAT-STRING> <DIRECTORY> [DIRECTORY,...]'.format(appname))
        print()
        print('FORMAT-STRING is a python modern-style format string, with the following')
        print('keys available:')
        print(' artist')
        print(' album')
        print(' title')
        print(' tracknumber')
        print(' discnumber')
        print()
        print('''Example FORMAT-STRING: '{tracknumber}. {artist} - {title}' ''')

    def get_tags(self, path):
        """Retrieve the tags for a file"""
        tags = mutagen.File(path, easy=True)
        res = {x: tags[x][0] for x in tags if x in ('artist',
                                                    'album',
                                                    'title',
                                                    'tracknumber',
                                                    'discnumber')}

        if '/' in res['tracknumber']:
            res['tracknumber'] = res['tracknumber'].split('/')[0]
        res['tracknumber'] = int(res['tracknumber'])

        if 'discnumber' not in res:
            res['discnumber'] = ''
        else:
            if '/' in res['discnumber']:
                res['discnumber'] = res['discnumber'].split('/')[0]
            res['discnumber'] = int(res['discnumber'])

        return res

    def handle_dir(self, directory, format_string):
        """Handle (rename) all music files in the specified directory"""
        tags = {}
        for f in filter(lambda x: re.search(self.filename_re, x, re.I), os.listdir(directory)):
            path = os.path.join(directory, f)
            tags[path] = self.get_tags(path)

        max_trackno = max(tags.values(), key=lambda x: x['tracknumber'])['tracknumber']
        trackno_digits = max(2, len(str(max_trackno)))
        for _, t in tags.iteritems():
            t['tracknumber'] = str(t['tracknumber']).zfill(trackno_digits)

        for old_path, t in sorted(tags.iteritems(), key=lambda x: x[1]['tracknumber']):
            ext = old_path.split('.')[-1]
            new_fn = sanitize_path_component(format_string.format(**t) + '.{}'.format(ext))
            new_path = os.path.join(directory, new_fn)
            if old_path != new_path:
                print('{} » {}'.format(old_path, new_path))
                os.rename(old_path, new_path)


if __name__ == '__main__':
    MusicRenamer().run(sys.argv)