web/lib/django/core/management/commands/dumpdata.py
changeset 38 77b6da96e6f1
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/lib/django/core/management/commands/dumpdata.py	Wed Jun 02 18:57:35 2010 +0200
@@ -0,0 +1,166 @@
+from django.core.exceptions import ImproperlyConfigured
+from django.core.management.base import BaseCommand, CommandError
+from django.core import serializers
+from django.db import connections, router, DEFAULT_DB_ALIAS
+from django.utils.datastructures import SortedDict
+
+from optparse import make_option
+
+class Command(BaseCommand):
+    option_list = BaseCommand.option_list + (
+        make_option('--format', default='json', dest='format',
+            help='Specifies the output serialization format for fixtures.'),
+        make_option('--indent', default=None, dest='indent', type='int',
+            help='Specifies the indent level to use when pretty-printing output'),
+        make_option('--database', action='store', dest='database',
+            default=DEFAULT_DB_ALIAS, help='Nominates a specific database to load '
+                'fixtures into. Defaults to the "default" database.'),
+        make_option('-e', '--exclude', dest='exclude',action='append', default=[],
+            help='App to exclude (use multiple --exclude to exclude multiple apps).'),
+        make_option('-n', '--natural', action='store_true', dest='use_natural_keys', default=False,
+            help='Use natural keys if they are available.'),
+    )
+    help = 'Output the contents of the database as a fixture of the given format.'
+    args = '[appname appname.ModelName ...]'
+
+    def handle(self, *app_labels, **options):
+        from django.db.models import get_app, get_apps, get_models, get_model
+
+        format = options.get('format','json')
+        indent = options.get('indent',None)
+        using = options.get('database', DEFAULT_DB_ALIAS)
+        connection = connections[using]
+        exclude = options.get('exclude',[])
+        show_traceback = options.get('traceback', False)
+        use_natural_keys = options.get('use_natural_keys', False)
+
+        excluded_apps = set(get_app(app_label) for app_label in exclude)
+
+        if len(app_labels) == 0:
+            app_list = SortedDict((app, None) for app in get_apps() if app not in excluded_apps)
+        else:
+            app_list = SortedDict()
+            for label in app_labels:
+                try:
+                    app_label, model_label = label.split('.')
+                    try:
+                        app = get_app(app_label)
+                    except ImproperlyConfigured:
+                        raise CommandError("Unknown application: %s" % app_label)
+
+                    model = get_model(app_label, model_label)
+                    if model is None:
+                        raise CommandError("Unknown model: %s.%s" % (app_label, model_label))
+
+                    if app in app_list.keys():
+                        if app_list[app] and model not in app_list[app]:
+                            app_list[app].append(model)
+                    else:
+                        app_list[app] = [model]
+                except ValueError:
+                    # This is just an app - no model qualifier
+                    app_label = label
+                    try:
+                        app = get_app(app_label)
+                    except ImproperlyConfigured:
+                        raise CommandError("Unknown application: %s" % app_label)
+                    app_list[app] = None
+
+        # Check that the serialization format exists; this is a shortcut to
+        # avoid collating all the objects and _then_ failing.
+        if format not in serializers.get_public_serializer_formats():
+            raise CommandError("Unknown serialization format: %s" % format)
+
+        try:
+            serializers.get_serializer(format)
+        except KeyError:
+            raise CommandError("Unknown serialization format: %s" % format)
+
+        # Now collate the objects to be serialized.
+        objects = []
+        for model in sort_dependencies(app_list.items()):
+            if not model._meta.proxy and router.allow_syncdb(using, model):
+                objects.extend(model._default_manager.using(using).all())
+
+        try:
+            return serializers.serialize(format, objects, indent=indent,
+                        use_natural_keys=use_natural_keys)
+        except Exception, e:
+            if show_traceback:
+                raise
+            raise CommandError("Unable to serialize database: %s" % e)
+
+def sort_dependencies(app_list):
+    """Sort a list of app,modellist pairs into a single list of models.
+
+    The single list of models is sorted so that any model with a natural key
+    is serialized before a normal model, and any model with a natural key
+    dependency has it's dependencies serialized first.
+    """
+    from django.db.models import get_model, get_models
+    # Process the list of models, and get the list of dependencies
+    model_dependencies = []
+    models = set()
+    for app, model_list in app_list:
+        if model_list is None:
+            model_list = get_models(app)
+
+        for model in model_list:
+            models.add(model)
+            # Add any explicitly defined dependencies
+            if hasattr(model, 'natural_key'):
+                deps = getattr(model.natural_key, 'dependencies', [])
+                if deps:
+                    deps = [get_model(*d.split('.')) for d in deps]
+            else:
+                deps = []
+
+            # Now add a dependency for any FK or M2M relation with
+            # a model that defines a natural key
+            for field in model._meta.fields:
+                if hasattr(field.rel, 'to'):
+                    rel_model = field.rel.to
+                    if hasattr(rel_model, 'natural_key'):
+                        deps.append(rel_model)
+            for field in model._meta.many_to_many:
+                rel_model = field.rel.to
+                if hasattr(rel_model, 'natural_key'):
+                    deps.append(rel_model)
+            model_dependencies.append((model, deps))
+
+    model_dependencies.reverse()
+    # Now sort the models to ensure that dependencies are met. This
+    # is done by repeatedly iterating over the input list of models.
+    # If all the dependencies of a given model are in the final list,
+    # that model is promoted to the end of the final list. This process
+    # continues until the input list is empty, or we do a full iteration
+    # over the input models without promoting a model to the final list.
+    # If we do a full iteration without a promotion, that means there are
+    # circular dependencies in the list.
+    model_list = []
+    while model_dependencies:
+        skipped = []
+        changed = False
+        while model_dependencies:
+            model, deps = model_dependencies.pop()
+
+            # If all of the models in the dependency list are either already
+            # on the final model list, or not on the original serialization list,
+            # then we've found another model with all it's dependencies satisfied.
+            found = True
+            for candidate in ((d not in models or d in model_list) for d in deps):
+                if not candidate:
+                    found = False
+            if found:
+                model_list.append(model)
+                changed = True
+            else:
+                skipped.append((model, deps))
+        if not changed:
+            raise CommandError("Can't resolve dependencies for %s in serialized app list." %
+                ', '.join('%s.%s' % (model._meta.app_label, model._meta.object_name)
+                for model, deps in sorted(skipped, key=lambda obj: obj[0].__name__))
+            )
+        model_dependencies = skipped
+
+    return model_list
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