mongoengine/mongoengine/document.py

102 lines
4.3 KiB
Python

from base import (DocumentMetaclass, TopLevelDocumentMetaclass, BaseDocument,
ValidationError)
from connection import _get_db
__all__ = ['Document', 'EmbeddedDocument']
class EmbeddedDocument(BaseDocument):
"""A :class:`~mongoengine.Document` that isn't stored in its own
collection. :class:`~mongoengine.EmbeddedDocument`\ s should be used as
fields on :class:`~mongoengine.Document`\ s through the
:class:`~mongoengine.EmbeddedDocumentField` field type.
"""
__metaclass__ = DocumentMetaclass
class Document(BaseDocument):
"""The base class used for defining the structure and properties of
collections of documents stored in MongoDB. Inherit from this class, and
add fields as class attributes to define a document's structure.
Individual documents may then be created by making instances of the
:class:`~mongoengine.Document` subclass.
By default, the MongoDB collection used to store documents created using a
:class:`~mongoengine.Document` subclass will be the name of the subclass
converted to lowercase. A different collection may be specified by
providing :attr:`collection` to the :attr:`meta` dictionary in the class
definition.
A :class:`~mongoengine.Document` subclass may be itself subclassed, to
create a specialised version of the document that will be stored in the
same collection. To facilitate this behaviour, `_cls` and `_types`
fields are added to documents (hidden though the MongoEngine interface
though). To disable this behaviour and remove the dependence on the
presence of `_cls` and `_types`, set :attr:`allow_inheritance` to
``False`` in the :attr:`meta` dictionary.
A :class:`~mongoengine.Document` may use a **Capped Collection** by
specifying :attr:`max_documents` and :attr:`max_size` in the :attr:`meta`
dictionary. :attr:`max_documents` is the maximum number of documents that
is allowed to be stored in the collection, and :attr:`max_size` is the
maximum size of the collection in bytes. If :attr:`max_size` is not
specified and :attr:`max_documents` is, :attr:`max_size` defaults to
10000000 bytes (10MB).
"""
__metaclass__ = TopLevelDocumentMetaclass
def save(self):
"""Save the :class:`~mongoengine.Document` to the database. If the
document already exists, it will be updated, otherwise it will be
created.
"""
self.validate()
object_id = self.__class__.objects._collection.save(self.to_mongo())
self.id = self._fields['id'].to_python(object_id)
def delete(self):
"""Delete the :class:`~mongoengine.Document` from the database. This
will only take effect if the document has been previously saved.
"""
object_id = self._fields['id'].to_mongo(self.id)
self.__class__.objects(id=object_id).delete()
def reload(self):
"""Reloads all attributes from the database.
"""
#object_id = self._fields['id'].to_mongo(self.id)
#obj = self.__class__.objects(id=object_id).first()
obj = self.__class__.objects(id=self.id).first()
for field in self._fields:
setattr(self, field, getattr(obj, field))
def validate(self):
"""Ensure that all fields' values are valid and that required fields
are present.
"""
# Get a list of tuples of field names and their current values
fields = [(field, getattr(self, name))
for name, field in self._fields.items()]
# Ensure that each field is matched to a valid value
for field, value in fields:
if value is not None:
try:
field.validate(value)
except (ValueError, AttributeError, AssertionError), e:
raise ValidationError('Invalid value for field of type "' +
field.__class__.__name__ + '"')
elif field.required:
raise ValidationError('Field "%s" is required' % field.name)
@classmethod
def drop_collection(cls):
"""Drops the entire collection associated with this
:class:`~mongoengine.Document` type from the database.
"""
db = _get_db()
db.drop_collection(cls._meta['collection'])