168 lines
7.4 KiB
Python
168 lines
7.4 KiB
Python
from django.core.exceptions import ImproperlyConfigured
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from django.core.management.base import BaseCommand, CommandError
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from django.core import serializers
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from django.db import connections, router, DEFAULT_DB_ALIAS
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from django.utils.datastructures import SortedDict
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from optparse import make_option
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class Command(BaseCommand):
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option_list = BaseCommand.option_list + (
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make_option('--format', default='json', dest='format',
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help='Specifies the output serialization format for fixtures.'),
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make_option('--indent', default=None, dest='indent', type='int',
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help='Specifies the indent level to use when pretty-printing output'),
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make_option('--database', action='store', dest='database',
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default=DEFAULT_DB_ALIAS, help='Nominates a specific database to load '
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'fixtures into. Defaults to the "default" database.'),
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make_option('-e', '--exclude', dest='exclude',action='append', default=[],
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help='App to exclude (use multiple --exclude to exclude multiple apps).'),
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make_option('-n', '--natural', action='store_true', dest='use_natural_keys', default=False,
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help='Use natural keys if they are available.'),
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)
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help = ("Output the contents of the database as a fixture of the given "
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"format (using each model's default manager).")
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args = '[appname appname.ModelName ...]'
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def handle(self, *app_labels, **options):
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from django.db.models import get_app, get_apps, get_models, get_model
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format = options.get('format','json')
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indent = options.get('indent',None)
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using = options.get('database', DEFAULT_DB_ALIAS)
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connection = connections[using]
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exclude = options.get('exclude',[])
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show_traceback = options.get('traceback', False)
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use_natural_keys = options.get('use_natural_keys', False)
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excluded_apps = set(get_app(app_label) for app_label in exclude)
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if len(app_labels) == 0:
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app_list = SortedDict((app, None) for app in get_apps() if app not in excluded_apps)
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else:
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app_list = SortedDict()
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for label in app_labels:
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try:
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app_label, model_label = label.split('.')
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try:
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app = get_app(app_label)
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except ImproperlyConfigured:
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raise CommandError("Unknown application: %s" % app_label)
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model = get_model(app_label, model_label)
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if model is None:
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raise CommandError("Unknown model: %s.%s" % (app_label, model_label))
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if app in app_list.keys():
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if app_list[app] and model not in app_list[app]:
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app_list[app].append(model)
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else:
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app_list[app] = [model]
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except ValueError:
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# This is just an app - no model qualifier
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app_label = label
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try:
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app = get_app(app_label)
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except ImproperlyConfigured:
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raise CommandError("Unknown application: %s" % app_label)
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app_list[app] = None
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# Check that the serialization format exists; this is a shortcut to
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# avoid collating all the objects and _then_ failing.
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if format not in serializers.get_public_serializer_formats():
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raise CommandError("Unknown serialization format: %s" % format)
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try:
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serializers.get_serializer(format)
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except KeyError:
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raise CommandError("Unknown serialization format: %s" % format)
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# Now collate the objects to be serialized.
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objects = []
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for model in sort_dependencies(app_list.items()):
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if not model._meta.proxy and router.allow_syncdb(using, model):
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objects.extend(model._default_manager.using(using).all())
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try:
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return serializers.serialize(format, objects, indent=indent,
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use_natural_keys=use_natural_keys)
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except Exception, e:
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if show_traceback:
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raise
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raise CommandError("Unable to serialize database: %s" % e)
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def sort_dependencies(app_list):
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"""Sort a list of app,modellist pairs into a single list of models.
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The single list of models is sorted so that any model with a natural key
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is serialized before a normal model, and any model with a natural key
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dependency has it's dependencies serialized first.
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"""
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from django.db.models import get_model, get_models
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# Process the list of models, and get the list of dependencies
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model_dependencies = []
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models = set()
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for app, model_list in app_list:
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if model_list is None:
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model_list = get_models(app)
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for model in model_list:
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models.add(model)
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# Add any explicitly defined dependencies
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if hasattr(model, 'natural_key'):
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deps = getattr(model.natural_key, 'dependencies', [])
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if deps:
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deps = [get_model(*d.split('.')) for d in deps]
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else:
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deps = []
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# Now add a dependency for any FK or M2M relation with
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# a model that defines a natural key
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for field in model._meta.fields:
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if hasattr(field.rel, 'to'):
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rel_model = field.rel.to
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if hasattr(rel_model, 'natural_key'):
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deps.append(rel_model)
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for field in model._meta.many_to_many:
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rel_model = field.rel.to
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if hasattr(rel_model, 'natural_key'):
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deps.append(rel_model)
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model_dependencies.append((model, deps))
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model_dependencies.reverse()
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# Now sort the models to ensure that dependencies are met. This
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# is done by repeatedly iterating over the input list of models.
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# If all the dependencies of a given model are in the final list,
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# that model is promoted to the end of the final list. This process
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# continues until the input list is empty, or we do a full iteration
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# over the input models without promoting a model to the final list.
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# If we do a full iteration without a promotion, that means there are
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# circular dependencies in the list.
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model_list = []
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while model_dependencies:
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skipped = []
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changed = False
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while model_dependencies:
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model, deps = model_dependencies.pop()
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# If all of the models in the dependency list are either already
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# on the final model list, or not on the original serialization list,
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# then we've found another model with all it's dependencies satisfied.
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found = True
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for candidate in ((d not in models or d in model_list) for d in deps):
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if not candidate:
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found = False
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if found:
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model_list.append(model)
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changed = True
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else:
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skipped.append((model, deps))
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if not changed:
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raise CommandError("Can't resolve dependencies for %s in serialized app list." %
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', '.join('%s.%s' % (model._meta.app_label, model._meta.object_name)
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for model, deps in sorted(skipped, key=lambda obj: obj[0].__name__))
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)
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model_dependencies = skipped
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return model_list
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