mongoengine/mongomap/collection.py

89 lines
2.6 KiB
Python

from connection import _get_db
class QuerySet(object):
"""A set of results returned from a query. Wraps a MongoDB cursor,
providing Document objects as the results.
"""
def __init__(self, document, cursor):
self._document = document
self._cursor = cursor
def next(self):
"""Wrap the result in a Document object.
"""
return self._document._from_son(self._cursor.next())
def count(self):
"""Count the selected elements in the query.
"""
return self._cursor.count()
def limit(self, n):
"""Limit the number of returned documents to.
"""
self._cursor.limit(n)
# Return self to allow chaining
return self
def skip(self, n):
"""Skip n documents before returning the results.
"""
self._cursor.skip(n)
return self
def __iter__(self):
return self
class CollectionManager(object):
def __init__(self, document):
"""Set up the collection manager for a specific document.
"""
db = _get_db()
self._document = document
self._collection_name = document._meta['collection']
# This will create the collection if it doesn't exist
self._collection = db[self._collection_name]
def _save_document(self, document):
"""Save the provided document to the collection.
"""
_id = self._collection.save(document._to_mongo())
document._id = _id
def _transform_query(self, **query):
"""Transform a query from Django-style format to Mongo format.
"""
operators = ['neq', 'gt', 'gte', 'lt', 'lte', 'in', 'nin', 'mod',
'all', 'size', 'exists']
mongo_query = {}
for key, value in query.items():
parts = key.split('__')
# Check for an operator and transform to mongo-style if there is
if parts[-1] in operators:
op = parts.pop()
value = {'$' + op: value}
key = '.'.join(parts)
mongo_query[key] = value
return mongo_query
def find(self, **query):
"""Query the collection for document matching the provided query.
"""
if query:
query = self._transform_query(**query)
return QuerySet(self._document, self._collection.find(query))
def find_one(self, **query):
"""Query the collection for document matching the provided query.
"""
if query:
query = self._transform_query(**query)
return self._document._from_son(self._collection.find_one(query))