med/media/management/commands/import_cds.py

from argparse import FileType
from sys import stdin

from django.core.management import BaseCommand
from media.models import Author, CD


class Command(BaseCommand):
    def add_arguments(self, parser):
        parser.add_argument('input', nargs='?',
                            type=FileType('r'),
                            default=stdin,
                            help="CD to be imported.")

    def handle(self, *args, **options):
        file = options["input"]
        cds = []
        for line in file:
            cds.append(line[:-1].split('|', 2))

        print("Registering", len(cds), "CDs")

        imported = 0

        for cd in cds:
            if len(cd) != 3:
                continue

            title = cd[0]
            side = cd[1]
            authors_str = cd[2].split('|')
            authors = [Author.objects.get_or_create(name=author)[0]
                       for author in authors_str]
            cd, created = CD.objects.get_or_create(
                title=title,
                side_identifier=side,
            )
            cd.authors.set(authors)
            cd.save()

            if not created:
                self.stderr.write(self.style.WARNING(
                    "One CD was already imported. Skipping..."))
            else:
                self.stdout.write(self.style.SUCCESS(
                    "CD imported"))
                imported += 1

        self.stdout.write(self.style.SUCCESS(
            "{count} CDs imported".format(count=imported)))