def __new__(mcs, name, bases, attrs):
flattened_bases = mcs._get_bases(bases)
super_new = super(TopLevelDocumentMetaclass, mcs).__new__
# Set default _meta data if base class, otherwise get user defined meta
if attrs.get('my_metaclass') == TopLevelDocumentMetaclass:
# defaults
attrs['_meta'] = {
'abstract': True,
'max_documents': None,
'max_size': None,
'ordering': [], # default ordering applied at runtime
'indexes': [], # indexes to be ensured at runtime
'id_field': None,
'index_background': False,
'index_drop_dups': False,
'index_opts': None,
'delete_rules': None,
# allow_inheritance can be True, False, and None. True means
# "allow inheritance", False means "don't allow inheritance",
# None means "do whatever your parent does, or don't allow
# inheritance if you're a top-level class".
'allow_inheritance': None,
}
attrs['_is_base_cls'] = True
attrs['_meta'].update(attrs.get('meta', {}))
else:
attrs['_meta'] = attrs.get('meta', {})
# Explicitly set abstract to false unless set
attrs['_meta']['abstract'] = attrs['_meta'].get('abstract', False)
attrs['_is_base_cls'] = False
# Set flag marking as document class - as opposed to an object mixin
attrs['_is_document'] = True
# Ensure queryset_class is inherited
if 'objects' in attrs:
manager = attrs['objects']
if hasattr(manager, 'queryset_class'):
attrs['_meta']['queryset_class'] = manager.queryset_class
# Clean up top level meta
if 'meta' in attrs:
del attrs['meta']
# Find the parent document class
parent_doc_cls = [
b for b in flattened_bases
if b.__class__ == TopLevelDocumentMetaclass
]
parent_doc_cls = None if not parent_doc_cls else parent_doc_cls[0]
# Prevent classes setting collection different to their parents
# If parent wasn't an abstract class
if (parent_doc_cls and 'collection' in attrs.get('_meta', {})
and not parent_doc_cls._meta.get('abstract', True)):
msg = 'Trying to set a collection on a subclass (%s)' % name
warnings.warn(msg, SyntaxWarning)
del attrs['_meta']['collection']
# Ensure abstract documents have abstract bases
if attrs.get('_is_base_cls') or attrs['_meta'].get('abstract'):
if (parent_doc_cls
and not parent_doc_cls._meta.get('abstract', False)):
msg = 'Abstract document cannot have non-abstract base'
raise ValueError(msg)
return super_new(mcs, name, bases, attrs)
# Merge base class metas.
# Uses a special MetaDict that handles various merging rules
meta = MetaDict()
for base in flattened_bases[::-1]:
# Add any mixin metadata from plain objects
if hasattr(base, 'meta'):
meta.merge(base.meta)
elif hasattr(base, '_meta'):
meta.merge(base._meta)
# Set collection in the meta if its callable
if (getattr(base, '_is_document', False)
and not base._meta.get('abstract')):
collection = meta.get('collection', None)
if callable(collection):
meta['collection'] = collection(base)
meta.merge(attrs.get('_meta', {})) # Top level meta
# Only simple classes (i.e. direct subclasses of Document) may set
# allow_inheritance to False. If the base Document allows inheritance,
# none of its subclasses can override allow_inheritance to False.
simple_class = all([
b._meta.get('abstract') for b in flattened_bases
if hasattr(b, '_meta')
])
if (not simple_class and meta['allow_inheritance'] is False
and not meta['abstract']):
raise ValueError('Only direct subclasses of Document may set '
'"allow_inheritance" to False')
# Set default collection name
if 'collection' not in meta:
meta['collection'] = ''.join('_%s' % c if c.isupper() else c
for c in name).strip('_').lower()
attrs['_meta'] = meta
# Call super and get the new class
new_class = super_new(mcs, name, bases, attrs)
meta = new_class._meta
# Set index specifications
meta['index_specs'] = new_class._build_index_specs(meta['indexes'])
# If collection is a callable - call it and set the value
collection = meta.get('collection')
if callable(collection):
new_class._meta['collection'] = collection(new_class)
# Provide a default queryset unless exists or one has been set
if 'objects' not in dir(new_class):
new_class.objects = QuerySetManager()
# Validate the fields and set primary key if needed
for field_name, field in iteritems(new_class._fields):
if field.primary_key:
# Ensure only one primary key is set
current_pk = new_class._meta.get('id_field')
if current_pk and current_pk != field_name:
raise ValueError('Cannot override primary key field')
# Set primary key
if not current_pk:
new_class._meta['id_field'] = field_name
new_class.id = field
# Set primary key if not defined by the document
new_class._auto_id_field = getattr(parent_doc_cls, '_auto_id_field',
False)
if not new_class._meta.get('id_field'):
# After 0.10, find not existing names, instead of overwriting
id_name, id_db_name = mcs.get_auto_id_names(new_class)
new_class._auto_id_field = True
new_class._meta['id_field'] = id_name
new_class._fields[id_name] = ObjectIdField(db_field=id_db_name)
new_class._fields[id_name].name = id_name
new_class.id = new_class._fields[id_name]
new_class._db_field_map[id_name] = id_db_name
new_class._reverse_db_field_map[id_db_name] = id_name
# Prepend id field to _fields_ordered
new_class._fields_ordered = (id_name, ) + new_class._fields_ordered
# Merge in exceptions with parent hierarchy
exceptions_to_merge = (DoesNotExist, MultipleObjectsReturned)
module = attrs.get('__module__')
for exc in exceptions_to_merge:
name = exc.__name__
parents = tuple(
getattr(base, name)
for base in flattened_bases if hasattr(base, name)) or (exc, )
# Create new exception and set to new_class
exception = type(name, parents, {'__module__': module})
setattr(new_class, name, exception)
return new_class
def __new__(mcs, name, bases, attrs):
flattened_bases = mcs._get_bases(bases)
super_new = super(TopLevelDocumentMetaclass, mcs).__new__
# Set default _meta data if base class, otherwise get user defined meta
if attrs.get("my_metaclass") == TopLevelDocumentMetaclass:
# defaults
attrs["_meta"] = {
"abstract": True,
"max_documents": None,
"max_size": None,
"ordering": [], # default ordering applied at runtime
"indexes": [], # indexes to be ensured at runtime
"id_field": None,
"index_background": False,
"index_opts": None,
"delete_rules": None,
# allow_inheritance can be True, False, and None. True means
# "allow inheritance", False means "don't allow inheritance",
# None means "do whatever your parent does, or don't allow
# inheritance if you're a top-level class".
"allow_inheritance": None,
}
attrs["_is_base_cls"] = True
attrs["_meta"].update(attrs.get("meta", {}))
else:
attrs["_meta"] = attrs.get("meta", {})
# Explicitly set abstract to false unless set
attrs["_meta"]["abstract"] = attrs["_meta"].get("abstract", False)
attrs["_is_base_cls"] = False
# Set flag marking as document class - as opposed to an object mixin
attrs["_is_document"] = True
# Ensure queryset_class is inherited
if "objects" in attrs:
manager = attrs["objects"]
if hasattr(manager, "queryset_class"):
attrs["_meta"]["queryset_class"] = manager.queryset_class
# Clean up top level meta
if "meta" in attrs:
del attrs["meta"]
# Find the parent document class
parent_doc_cls = [
b for b in flattened_bases if b.__class__ == TopLevelDocumentMetaclass
]
parent_doc_cls = None if not parent_doc_cls else parent_doc_cls[0]
# Prevent classes setting collection different to their parents
# If parent wasn't an abstract class
if (
parent_doc_cls
and "collection" in attrs.get("_meta", {})
and not parent_doc_cls._meta.get("abstract", True)
):
msg = "Trying to set a collection on a subclass (%s)" % name
warnings.warn(msg, SyntaxWarning)
del attrs["_meta"]["collection"]
# Ensure abstract documents have abstract bases
if attrs.get("_is_base_cls") or attrs["_meta"].get("abstract"):
if parent_doc_cls and not parent_doc_cls._meta.get("abstract", False):
msg = "Abstract document cannot have non-abstract base"
raise ValueError(msg)
return super_new(mcs, name, bases, attrs)
# Merge base class metas.
# Uses a special MetaDict that handles various merging rules
meta = MetaDict()
for base in flattened_bases[::-1]:
# Add any mixin metadata from plain objects
if hasattr(base, "meta"):
meta.merge(base.meta)
elif hasattr(base, "_meta"):
meta.merge(base._meta)
# Set collection in the meta if its callable
if getattr(base, "_is_document", False) and not base._meta.get("abstract"):
collection = meta.get("collection", None)
if callable(collection):
meta["collection"] = collection(base)
meta.merge(attrs.get("_meta", {})) # Top level meta
# Only simple classes (i.e. direct subclasses of Document) may set
# allow_inheritance to False. If the base Document allows inheritance,
# none of its subclasses can override allow_inheritance to False.
simple_class = all(
[b._meta.get("abstract") for b in flattened_bases if hasattr(b, "_meta")]
)
if (
not simple_class
and meta["allow_inheritance"] is False
and not meta["abstract"]
):
raise ValueError(
"Only direct subclasses of Document may set "
'"allow_inheritance" to False'
)
# Set default collection name
if "collection" not in meta:
meta["collection"] = (
"".join("_%s" % c if c.isupper() else c for c in name)
.strip("_")
.lower()
)
attrs["_meta"] = meta
# Call super and get the new class
new_class = super_new(mcs, name, bases, attrs)
meta = new_class._meta
# Set index specifications
meta["index_specs"] = new_class._build_index_specs(meta["indexes"])
# If collection is a callable - call it and set the value
collection = meta.get("collection")
if callable(collection):
new_class._meta["collection"] = collection(new_class)
# Provide a default queryset unless exists or one has been set
if "objects" not in dir(new_class):
new_class.objects = QuerySetManager()
# Validate the fields and set primary key if needed
for field_name, field in iteritems(new_class._fields):
if field.primary_key:
# Ensure only one primary key is set
current_pk = new_class._meta.get("id_field")
if current_pk and current_pk != field_name:
raise ValueError("Cannot override primary key field")
# Set primary key
if not current_pk:
new_class._meta["id_field"] = field_name
new_class.id = field
# If the document doesn't explicitly define a primary key field, create
# one. Make it an ObjectIdField and give it a non-clashing name ("id"
# by default, but can be different if that one's taken).
if not new_class._meta.get("id_field"):
id_name, id_db_name = mcs.get_auto_id_names(new_class)
new_class._meta["id_field"] = id_name
new_class._fields[id_name] = ObjectIdField(db_field=id_db_name)
new_class._fields[id_name].name = id_name
new_class.id = new_class._fields[id_name]
new_class._db_field_map[id_name] = id_db_name
new_class._reverse_db_field_map[id_db_name] = id_name
# Prepend the ID field to _fields_ordered (so that it's *always*
# the first field).
new_class._fields_ordered = (id_name,) + new_class._fields_ordered
# Merge in exceptions with parent hierarchy.
exceptions_to_merge = (DoesNotExist, MultipleObjectsReturned)
module = attrs.get("__module__")
for exc in exceptions_to_merge:
name = exc.__name__
parents = tuple(
getattr(base, name) for base in flattened_bases if hasattr(base, name)
) or (exc,)
# Create a new exception and set it as an attribute on the new
# class.
exception = type(name, parents, {"__module__": module})
setattr(new_class, name, exception)
return new_class