Merge branch 'master' of https://github.com/MongoEngine/mongoengine into swat_url_fix

mongoengine/__init__.py

@@ -23,7 +23,7 @@ __all__ = (list(document.__all__) + list(fields.__all__) +
            list(signals.__all__) + list(errors.__all__))
 
 
-VERSION = (0, 11, 0)
+VERSION = (0, 15, 3)
 
 
 def get_version():

mongoengine/base/__init__.py

@@ -15,7 +15,7 @@ __all__ = (
     'UPDATE_OPERATORS', '_document_registry', 'get_document',
 
     # datastructures
-    'BaseDict', 'BaseList', 'EmbeddedDocumentList',
+    'BaseDict', 'BaseList', 'EmbeddedDocumentList', 'LazyReference',
 
     # document
     'BaseDocument',

mongoengine/base/common.py

@@ -3,9 +3,10 @@ from mongoengine.errors import NotRegistered
 __all__ = ('UPDATE_OPERATORS', 'get_document', '_document_registry')
 
 
-UPDATE_OPERATORS = set(['set', 'unset', 'inc', 'dec', 'pop', 'push',
-                        'push_all', 'pull', 'pull_all', 'add_to_set',
-                        'set_on_insert', 'min', 'max'])
+UPDATE_OPERATORS = {'set', 'unset', 'inc', 'dec', 'mul',
+                    'pop', 'push', 'push_all', 'pull',
+                    'pull_all', 'add_to_set', 'set_on_insert',
+                    'min', 'max', 'rename'}
 
 
 _document_registry = {}

mongoengine/base/datastructures.py

@@ -1,12 +1,13 @@
 import itertools
 import weakref
 
+from bson import DBRef
 import six
 
 from mongoengine.common import _import_class
 from mongoengine.errors import DoesNotExist, MultipleObjectsReturned
 
-__all__ = ('BaseDict', 'BaseList', 'EmbeddedDocumentList')
+__all__ = ('BaseDict', 'BaseList', 'EmbeddedDocumentList', 'LazyReference')
 
 
 class BaseDict(dict):
@@ -127,8 +128,8 @@ class BaseList(list):
         return value
 
     def __iter__(self):
-        for i in xrange(self.__len__()):
-            yield self[i]
+        for v in super(BaseList, self).__iter__():
+            yield v
 
     def __setitem__(self, key, value, *args, **kwargs):
         if isinstance(key, slice):
@@ -137,11 +138,8 @@ class BaseList(list):
             self._mark_as_changed(key)
         return super(BaseList, self).__setitem__(key, value)
 
-    def __delitem__(self, key, *args, **kwargs):
-        if isinstance(key, slice):
-            self._mark_as_changed()
-        else:
-            self._mark_as_changed(key)
+    def __delitem__(self, key):
+        self._mark_as_changed()
         return super(BaseList, self).__delitem__(key)
 
     def __setslice__(self, *args, **kwargs):
@@ -189,7 +187,7 @@ class BaseList(list):
         self._mark_as_changed()
         return super(BaseList, self).remove(*args, **kwargs)
 
-    def reverse(self, *args, **kwargs):
+    def reverse(self):
         self._mark_as_changed()
         return super(BaseList, self).reverse()
 
@@ -236,6 +234,9 @@ class EmbeddedDocumentList(BaseList):
         Filters the list by only including embedded documents with the
         given keyword arguments.
 
+        This method only supports simple comparison (e.g: .filter(name='John Doe'))
+        and does not support operators like __gte, __lte, __icontains like queryset.filter does
+
         :param kwargs: The keyword arguments corresponding to the fields to
          filter on. *Multiple arguments are treated as if they are ANDed
          together.*
@@ -353,7 +354,8 @@ class EmbeddedDocumentList(BaseList):
 
     def update(self, **update):
         """
-        Updates the embedded documents with the given update values.
+        Updates the embedded documents with the given replacement values. This
+        function does not support mongoDB update operators such as ``inc__``.
 
         .. note::
             The embedded document changes are not automatically saved
@@ -375,7 +377,7 @@ class EmbeddedDocumentList(BaseList):
 
 class StrictDict(object):
     __slots__ = ()
-    _special_fields = set(['get', 'pop', 'iteritems', 'items', 'keys', 'create'])
+    _special_fields = {'get', 'pop', 'iteritems', 'items', 'keys', 'create'}
     _classes = {}
 
     def __init__(self, **kwargs):
@@ -432,7 +434,7 @@ class StrictDict(object):
     def __eq__(self, other):
         return self.items() == other.items()
 
-    def __neq__(self, other):
+    def __ne__(self, other):
         return self.items() != other.items()
 
     @classmethod
@@ -450,40 +452,40 @@ class StrictDict(object):
         return cls._classes[allowed_keys]
 
 
-class SemiStrictDict(StrictDict):
-    __slots__ = ('_extras', )
-    _classes = {}
+class LazyReference(DBRef):
+    __slots__ = ('_cached_doc', 'passthrough', 'document_type')
 
-    def __getattr__(self, attr):
-        try:
-            super(SemiStrictDict, self).__getattr__(attr)
-        except AttributeError:
-            try:
-                return self.__getattribute__('_extras')[attr]
-            except KeyError as e:
-                raise AttributeError(e)
+    def fetch(self, force=False):
+        if not self._cached_doc or force:
+            self._cached_doc = self.document_type.objects.get(pk=self.pk)
+            if not self._cached_doc:
+                raise DoesNotExist('Trying to dereference unknown document %s' % (self))
+        return self._cached_doc
 
-    def __setattr__(self, attr, value):
-        try:
-            super(SemiStrictDict, self).__setattr__(attr, value)
-        except AttributeError:
-            try:
-                self._extras[attr] = value
-            except AttributeError:
-                self._extras = {attr: value}
+    @property
+    def pk(self):
+        return self.id
 
-    def __delattr__(self, attr):
-        try:
-            super(SemiStrictDict, self).__delattr__(attr)
-        except AttributeError:
-            try:
-                del self._extras[attr]
-            except KeyError as e:
-                raise AttributeError(e)
+    def __init__(self, document_type, pk, cached_doc=None, passthrough=False):
+        self.document_type = document_type
+        self._cached_doc = cached_doc
+        self.passthrough = passthrough
+        super(LazyReference, self).__init__(self.document_type._get_collection_name(), pk)
 
-    def __iter__(self):
+    def __getitem__(self, name):
+        if not self.passthrough:
+            raise KeyError()
+        document = self.fetch()
+        return document[name]
+
+    def __getattr__(self, name):
+        if not object.__getattribute__(self, 'passthrough'):
+            raise AttributeError()
+        document = self.fetch()
         try:
-            extras_iter = iter(self.__getattribute__('_extras'))
-        except AttributeError:
-            extras_iter = ()
-        return itertools.chain(super(SemiStrictDict, self).__iter__(), extras_iter)
+            return document[name]
+        except KeyError:
+            raise AttributeError()
+
+    def __repr__(self):
+        return "<LazyReference(%s, %r)>" % (self.document_type, self.pk)

mongoengine/base/document.py

@@ -13,13 +13,14 @@ from mongoengine import signals
 from mongoengine.base.common import get_document
 from mongoengine.base.datastructures import (BaseDict, BaseList,
                                              EmbeddedDocumentList,
-                                             SemiStrictDict, StrictDict)
+                                             LazyReference,
+                                             StrictDict)
 from mongoengine.base.fields import ComplexBaseField
 from mongoengine.common import _import_class
 from mongoengine.errors import (FieldDoesNotExist, InvalidDocumentError,
                                 LookUpError, OperationError, ValidationError)
 
-__all__ = ('BaseDocument',)
+__all__ = ('BaseDocument', 'NON_FIELD_ERRORS')
 
 NON_FIELD_ERRORS = '__all__'
 
@@ -79,8 +80,7 @@ class BaseDocument(object):
         if self.STRICT and not self._dynamic:
             self._data = StrictDict.create(allowed_keys=self._fields_ordered)()
         else:
-            self._data = SemiStrictDict.create(
-                allowed_keys=self._fields_ordered)()
+            self._data = {}
 
         self._dynamic_fields = SON()
 
@@ -100,13 +100,11 @@ class BaseDocument(object):
             for key, value in values.iteritems():
                 if key in self._fields or key == '_id':
                     setattr(self, key, value)
-                elif self._dynamic:
+                else:
                     dynamic_data[key] = value
         else:
             FileField = _import_class('FileField')
             for key, value in values.iteritems():
-                if key == '__auto_convert':
-                    continue
                 key = self._reverse_db_field_map.get(key, key)
                 if key in self._fields or key in ('id', 'pk', '_cls'):
                     if __auto_convert and value is not None:
@@ -147,7 +145,7 @@ class BaseDocument(object):
 
             if not hasattr(self, name) and not name.startswith('_'):
                 DynamicField = _import_class('DynamicField')
-                field = DynamicField(db_field=name)
+                field = DynamicField(db_field=name, null=True)
                 field.name = name
                 self._dynamic_fields[name] = field
                 self._fields_ordered += (name,)
@@ -272,13 +270,6 @@ class BaseDocument(object):
     def __ne__(self, other):
         return not self.__eq__(other)
 
-    def __hash__(self):
-        if getattr(self, 'pk', None) is None:
-            # For new object
-            return super(BaseDocument, self).__hash__()
-        else:
-            return hash(self.pk)
-
     def clean(self):
         """
         Hook for doing document level data cleaning before validation is run.
@@ -311,7 +302,7 @@ class BaseDocument(object):
         data['_cls'] = self._class_name
 
         # only root fields ['test1.a', 'test2'] => ['test1', 'test2']
-        root_fields = set([f.split('.')[0] for f in fields])
+        root_fields = {f.split('.')[0] for f in fields}
 
         for field_name in self:
             if root_fields and field_name not in root_fields:
@@ -344,7 +335,7 @@ class BaseDocument(object):
                 value = field.generate()
                 self._data[field_name] = value
 
-            if value is not None:
+            if (value is not None) or (field.null):
                 if use_db_field:
                     data[field.db_field] = value
                 else:
@@ -402,16 +393,26 @@ class BaseDocument(object):
             raise ValidationError(message, errors=errors)
 
     def to_json(self, *args, **kwargs):
-        """Converts a document to JSON.
-        :param use_db_field: Set to True by default but enables the output of the json structure with the field names
-            and not the mongodb store db_names in case of set to False
+        """Convert this document to JSON.
+
+        :param use_db_field: Serialize field names as they appear in
+            MongoDB (as opposed to attribute names on this document).
+            Defaults to True.
         """
         use_db_field = kwargs.pop('use_db_field', True)
         return json_util.dumps(self.to_mongo(use_db_field), *args, **kwargs)
 
     @classmethod
     def from_json(cls, json_data, created=False):
-        """Converts json data to an unsaved document instance"""
+        """Converts json data to a Document instance
+
+        :param json_data: The json data to load into the Document
+        :param created: If True, the document will be considered as a brand new document
+                        If False and an id is provided, it will consider that the data being
+                        loaded corresponds to what's already in the database (This has an impact of subsequent call to .save())
+                        If False and no id is provided, it will consider the data as a new document
+                        (default ``False``)
+        """
         return cls._from_son(json_util.loads(json_data), created=created)
 
     def __expand_dynamic_values(self, name, value):
@@ -494,7 +495,7 @@ class BaseDocument(object):
                 else:
                     data = getattr(data, part, None)
 
-                if hasattr(data, '_changed_fields'):
+                if not isinstance(data, LazyReference) and hasattr(data, '_changed_fields'):
                     if getattr(data, '_is_document', False):
                         continue
 
@@ -566,7 +567,7 @@ class BaseDocument(object):
                     continue
                 elif isinstance(field, SortedListField) and field._ordering:
                     # if ordering is affected whole list is changed
-                    if any(map(lambda d: field._ordering in d._changed_fields, data)):
+                    if any(field._ordering in d._changed_fields for d in data):
                         changed_fields.append(db_field_name)
                         continue
 
@@ -675,12 +676,20 @@ class BaseDocument(object):
         if not only_fields:
             only_fields = []
 
+        if son and not isinstance(son, dict):
+            raise ValueError("The source SON object needs to be of type 'dict'")
+
         # Get the class name from the document, falling back to the given
         # class if unavailable
         class_name = son.get('_cls', cls._class_name)
 
-        # Convert SON to a dict, making sure each key is a string
-        data = {str(key): value for key, value in son.iteritems()}
+        # Convert SON to a data dict, making sure each key is a string and
+        # corresponds to the right db field.
+        data = {}
+        for key, value in son.iteritems():
+            key = str(key)
+            key = cls._db_field_map.get(key, key)
+            data[key] = value
 
         # Return correct subclass for document type
         if class_name != cls._class_name:
@@ -1077,5 +1086,11 @@ class BaseDocument(object):
         """Return the display value for a choice field"""
         value = getattr(self, field.name)
         if field.choices and isinstance(field.choices[0], (list, tuple)):
-            return dict(field.choices).get(value, value)
+            if value is None:
+                return None
+            sep = getattr(field, 'display_sep', ' ')
+            values = value if field.__class__.__name__ in ('ListField', 'SortedListField') else [value]
+            return sep.join([
+                six.text_type(dict(field.choices).get(val, val))
+                for val in values or []])
         return value

mongoengine/base/fields.py

@@ -41,7 +41,7 @@ class BaseField(object):
         """
         :param db_field: The database field to store this field in
             (defaults to the name of the field)
-        :param name: Depreciated - use db_field
+        :param name: Deprecated - use db_field
         :param required: If the field is required. Whether it has to have a
             value or not. Defaults to False.
         :param default: (optional) The default value for this field if no value
@@ -55,7 +55,7 @@ class BaseField(object):
             field.  Generally this is deprecated in favour of the
             `FIELD.validate` method
         :param choices: (optional) The valid choices
-        :param null: (optional) Is the field value can be null. If no and there is a default value
+        :param null: (optional) If the field value can be null. If no and there is a default value
             then the default value is set
         :param sparse: (optional) `sparse=True` combined with `unique=True` and `required=False`
             means that uniqueness won't be enforced for `None` values
@@ -81,6 +81,24 @@ class BaseField(object):
         self.sparse = sparse
         self._owner_document = None
 
+        # Make sure db_field is a string (if it's explicitly defined).
+        if (
+            self.db_field is not None and
+            not isinstance(self.db_field, six.string_types)
+        ):
+            raise TypeError('db_field should be a string.')
+
+        # Make sure db_field doesn't contain any forbidden characters.
+        if isinstance(self.db_field, six.string_types) and (
+            '.' in self.db_field or
+            '\0' in self.db_field or
+            self.db_field.startswith('$')
+        ):
+            raise ValueError(
+                'field names cannot contain dots (".") or null characters '
+                '("\\0"), and they must not start with a dollar sign ("$").'
+            )
+
         # Detect and report conflicts between metadata and base properties.
         conflicts = set(dir(self)) & set(kwargs)
         if conflicts:
@@ -112,7 +130,6 @@ class BaseField(object):
     def __set__(self, instance, value):
         """Descriptor for assigning a value to a field in a document.
         """
-
         # If setting to None and there is a default
         # Then set the value to the default value
         if value is None:
@@ -182,7 +199,8 @@ class BaseField(object):
         EmbeddedDocument = _import_class('EmbeddedDocument')
 
         choice_list = self.choices
-        if isinstance(choice_list[0], (list, tuple)):
+        if isinstance(next(iter(choice_list)), (list, tuple)):
+            # next(iter) is useful for sets
             choice_list = [k for k, _ in choice_list]
 
         # Choices which are other types of Documents
@@ -194,8 +212,10 @@ class BaseField(object):
                     )
                 )
         # Choices which are types other than Documents
-        elif value not in choice_list:
-            self.error('Value must be one of %s' % six.text_type(choice_list))
+        else:
+            values = value if isinstance(value, (list, tuple)) else [value]
+            if len(set(values) - set(choice_list)):
+                self.error('Value must be one of %s' % six.text_type(choice_list))
 
     def _validate(self, value, **kwargs):
         # Check the Choices Constraint
@@ -481,7 +501,7 @@ class GeoJsonBaseField(BaseField):
     def validate(self, value):
         """Validate the GeoJson object based on its type."""
         if isinstance(value, dict):
-            if set(value.keys()) == set(['type', 'coordinates']):
+            if set(value.keys()) == {'type', 'coordinates'}:
                 if value['type'] != self._type:
                     self.error('%s type must be "%s"' %
                                (self._name, self._type))

mongoengine/base/utils.py

@@ -0,0 +1,22 @@
+import re
+
+
+class LazyRegexCompiler(object):
+    """Descriptor to allow lazy compilation of regex"""
+
+    def __init__(self, pattern, flags=0):
+        self._pattern = pattern
+        self._flags = flags
+        self._compiled_regex = None
+
+    @property
+    def compiled_regex(self):
+        if self._compiled_regex is None:
+            self._compiled_regex = re.compile(self._pattern, self._flags)
+        return self._compiled_regex
+
+    def __get__(self, obj, objtype):
+        return self.compiled_regex
+
+    def __set__(self, instance, value):
+        raise AttributeError("Can not set attribute LazyRegexCompiler")

mongoengine/common.py

@@ -34,7 +34,10 @@ def _import_class(cls_name):
     queryset_classes = ('OperationError',)
     deref_classes = ('DeReference',)
 
-    if cls_name in doc_classes:
+    if cls_name == 'BaseDocument':
+        from mongoengine.base import document as module
+        import_classes = ['BaseDocument']
+    elif cls_name in doc_classes:
         from mongoengine import document as module
         import_classes = doc_classes
     elif cls_name in field_classes:

mongoengine/connection.py

@@ -28,7 +28,7 @@ _connections = {}
 _dbs = {}
 
 
-def register_connection(alias, name=None, host=None, port=None,
+def register_connection(alias, db=None, name=None, host=None, port=None,
                         read_preference=READ_PREFERENCE,
                         username=None, password=None,
                         authentication_source=None,
@@ -39,6 +39,7 @@ def register_connection(alias, name=None, host=None, port=None,
     :param alias: the name that will be used to refer to this connection
         throughout MongoEngine
     :param name: the name of the specific database to use
+    :param db: the name of the database to use, for compatibility with connect
     :param host: the host name of the :program:`mongod` instance to connect to
     :param port: the port that the :program:`mongod` instance is running on
     :param read_preference: The read preference for the collection
@@ -51,12 +52,14 @@ def register_connection(alias, name=None, host=None, port=None,
         MONGODB-CR (MongoDB Challenge Response protocol) for older servers.
     :param is_mock: explicitly use mongomock for this connection
         (can also be done by using `mongomock://` as db host prefix)
-    :param kwargs: allow ad-hoc parameters to be passed into the pymongo driver
+    :param kwargs: ad-hoc parameters to be passed into the pymongo driver,
+        for example maxpoolsize, tz_aware, etc. See the documentation
+        for pymongo's `MongoClient` for a full list.
 
     .. versionchanged:: 0.10.6 - added mongomock support
     """
     conn_settings = {
-        'name': name or 'test',
+        'name': name or db or 'test',
         'host': host or 'localhost',
         'port': port or 27017,
         'read_preference': read_preference,
@@ -66,9 +69,9 @@ def register_connection(alias, name=None, host=None, port=None,
         'authentication_mechanism': authentication_mechanism
     }
 
-    # Handle uri style connections
     conn_host = conn_settings['host']
-    # host can be a list or a string, so if string, force to a list
+
+    # Host can be a list or a string, so if string, force to a list.
     if isinstance(conn_host, six.string_types):
         conn_host = [conn_host]
 
@@ -96,11 +99,23 @@ def register_connection(alias, name=None, host=None, port=None,
 
             uri_options = uri_dict['options']
             if 'replicaset' in uri_options:
-                conn_settings['replicaSet'] = True
+                conn_settings['replicaSet'] = uri_options['replicaset']
             if 'authsource' in uri_options:
                 conn_settings['authentication_source'] = uri_options['authsource']
             if 'authmechanism' in uri_options:
                 conn_settings['authentication_mechanism'] = uri_options['authmechanism']
+            if IS_PYMONGO_3 and 'readpreference' in uri_options:
+                read_preferences = (
+                    ReadPreference.NEAREST,
+                    ReadPreference.PRIMARY,
+                    ReadPreference.PRIMARY_PREFERRED,
+                    ReadPreference.SECONDARY,
+                    ReadPreference.SECONDARY_PREFERRED)
+                read_pf_mode = uri_options['readpreference'].lower()
+                for preference in read_preferences:
+                    if preference.name.lower() == read_pf_mode:
+                        conn_settings['read_preference'] = preference
+                        break
         else:
             resolved_hosts.append(entity)
     conn_settings['host'] = resolved_hosts
@@ -144,13 +159,14 @@ def get_connection(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
         raise MongoEngineConnectionError(msg)
 
     def _clean_settings(settings_dict):
-        irrelevant_fields = set([
-            'name', 'username', 'password', 'authentication_source',
-            'authentication_mechanism'
-        ])
+        # set literal more efficient than calling set function
+        irrelevant_fields_set = {
+            'name', 'username', 'password',
+            'authentication_source', 'authentication_mechanism'
+        }
         return {
             k: v for k, v in settings_dict.items()
-            if k not in irrelevant_fields
+            if k not in irrelevant_fields_set
         }
 
     # Retrieve a copy of the connection settings associated with the requested
@@ -170,23 +186,22 @@ def get_connection(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
     else:
         connection_class = MongoClient
 
-        # Handle replica set connections
-        if 'replicaSet' in conn_settings:
+        # For replica set connections with PyMongo 2.x, use
+        # MongoReplicaSetClient.
+        # TODO remove this once we stop supporting PyMongo 2.x.
+        if 'replicaSet' in conn_settings and not IS_PYMONGO_3:
+            connection_class = MongoReplicaSetClient
+            conn_settings['hosts_or_uri'] = conn_settings.pop('host', None)
+
+            # hosts_or_uri has to be a string, so if 'host' was provided
+            # as a list, join its parts and separate them by ','
+            if isinstance(conn_settings['hosts_or_uri'], list):
+                conn_settings['hosts_or_uri'] = ','.join(
+                    conn_settings['hosts_or_uri'])
 
             # Discard port since it can't be used on MongoReplicaSetClient
             conn_settings.pop('port', None)
 
-            # Discard replicaSet if it's not a string
-            if not isinstance(conn_settings['replicaSet'], six.string_types):
-                del conn_settings['replicaSet']
-
-            # For replica set connections with PyMongo 2.x, use
-            # MongoReplicaSetClient.
-            # TODO remove this once we stop supporting PyMongo 2.x.
-            if not IS_PYMONGO_3:
-                connection_class = MongoReplicaSetClient
-                conn_settings['hosts_or_uri'] = conn_settings.pop('host', None)
-
     # Iterate over all of the connection settings and if a connection with
     # the same parameters is already established, use it instead of creating
     # a new one.
@@ -242,9 +257,12 @@ def connect(db=None, alias=DEFAULT_CONNECTION_NAME, **kwargs):
     running on the default port on localhost. If authentication is needed,
     provide username and password arguments as well.
 
-    Multiple databases are supported by using aliases.  Provide a separate
+    Multiple databases are supported by using aliases. Provide a separate
     `alias` to connect to a different instance of :program:`mongod`.
 
+    See the docstring for `register_connection` for more details about all
+    supported kwargs.
+
     .. versionchanged:: 0.6 - added multiple database support.
     """
     if alias not in _connections:

mongoengine/context_managers.py

@@ -1,9 +1,11 @@
+from contextlib import contextmanager
+from pymongo.write_concern import WriteConcern
 from mongoengine.common import _import_class
 from mongoengine.connection import DEFAULT_CONNECTION_NAME, get_db
 
 
 __all__ = ('switch_db', 'switch_collection', 'no_dereference',
-           'no_sub_classes', 'query_counter')
+           'no_sub_classes', 'query_counter', 'set_write_concern')
 
 
 class switch_db(object):
@@ -143,66 +145,83 @@ class no_sub_classes(object):
         :param cls: the class to turn querying sub classes on
         """
         self.cls = cls
+        self.cls_initial_subclasses = None
 
     def __enter__(self):
         """Change the objects default and _auto_dereference values."""
-        self.cls._all_subclasses = self.cls._subclasses
-        self.cls._subclasses = (self.cls,)
+        self.cls_initial_subclasses = self.cls._subclasses
+        self.cls._subclasses = (self.cls._class_name,)
         return self.cls
 
     def __exit__(self, t, value, traceback):
         """Reset the default and _auto_dereference values."""
-        self.cls._subclasses = self.cls._all_subclasses
-        delattr(self.cls, '_all_subclasses')
-        return self.cls
+        self.cls._subclasses = self.cls_initial_subclasses
 
 
 class query_counter(object):
-    """Query_counter context manager to get the number of queries."""
+    """Query_counter context manager to get the number of queries.
+    This works by updating the `profiling_level` of the database so that all queries get logged,
+    resetting the db.system.profile collection at the beginnig of the context and counting the new entries.
+
+    This was designed for debugging purpose. In fact it is a global counter so queries issued by other threads/processes
+    can interfere with it
+
+    Be aware that:
+    - Iterating over large amount of documents (>101) makes pymongo issue `getmore` queries to fetch the next batch of
+        documents (https://docs.mongodb.com/manual/tutorial/iterate-a-cursor/#cursor-batches)
+    - Some queries are ignored by default by the counter (killcursors, db.system.indexes)
+    """
 
     def __init__(self):
-        """Construct the query_counter."""
-        self.counter = 0
+        """Construct the query_counter
+        """
         self.db = get_db()
+        self.initial_profiling_level = None
+        self._ctx_query_counter = 0             # number of queries issued by the context
 
-    def __enter__(self):
-        """On every with block we need to drop the profile collection."""
+        self._ignored_query = {
+            'ns':
+                {'$ne': '%s.system.indexes' % self.db.name},
+            'op':
+                {'$ne': 'killcursors'}
+        }
+
+    def _turn_on_profiling(self):
+        self.initial_profiling_level = self.db.profiling_level()
         self.db.set_profiling_level(0)
         self.db.system.profile.drop()
         self.db.set_profiling_level(2)
+
+    def _resets_profiling(self):
+        self.db.set_profiling_level(self.initial_profiling_level)
+
+    def __enter__(self):
+        self._turn_on_profiling()
         return self
 
     def __exit__(self, t, value, traceback):
-        """Reset the profiling level."""
-        self.db.set_profiling_level(0)
+        self._resets_profiling()
 
     def __eq__(self, value):
-        """== Compare querycounter."""
         counter = self._get_count()
         return value == counter
 
     def __ne__(self, value):
-        """!= Compare querycounter."""
         return not self.__eq__(value)
 
     def __lt__(self, value):
-        """< Compare querycounter."""
         return self._get_count() < value
 
     def __le__(self, value):
-        """<= Compare querycounter."""
         return self._get_count() <= value
 
     def __gt__(self, value):
-        """> Compare querycounter."""
         return self._get_count() > value
 
     def __ge__(self, value):
-        """>= Compare querycounter."""
         return self._get_count() >= value
 
     def __int__(self):
-        """int representation."""
         return self._get_count()
 
     def __repr__(self):
@@ -210,8 +229,17 @@ class query_counter(object):
         return u"%s" % self._get_count()
 
     def _get_count(self):
-        """Get the number of queries."""
-        ignore_query = {'ns': {'$ne': '%s.system.indexes' % self.db.name}}
-        count = self.db.system.profile.find(ignore_query).count() - self.counter
-        self.counter += 1
+        """Get the number of queries by counting the current number of entries in db.system.profile
+        and substracting the queries issued by this context. In fact everytime this is called, 1 query is
+        issued so we need to balance that
+        """
+        count = self.db.system.profile.find(self._ignored_query).count() - self._ctx_query_counter
+        self._ctx_query_counter += 1    # Account for the query we just issued to gather the information
         return count
+
+
+@contextmanager
+def set_write_concern(collection, write_concerns):
+    combined_concerns = dict(collection.write_concern.document.items())
+    combined_concerns.update(write_concerns)
+    yield collection.with_options(write_concern=WriteConcern(**combined_concerns))

mongoengine/dereference.py

@@ -3,6 +3,7 @@ import six
 
 from mongoengine.base import (BaseDict, BaseList, EmbeddedDocumentList,
                               TopLevelDocumentMetaclass, get_document)
+from mongoengine.base.datastructures import LazyReference
 from mongoengine.connection import get_db
 from mongoengine.document import Document, EmbeddedDocument
 from mongoengine.fields import DictField, ListField, MapField, ReferenceField
@@ -99,7 +100,10 @@ class DeReference(object):
             if isinstance(item, (Document, EmbeddedDocument)):
                 for field_name, field in item._fields.iteritems():
                     v = item._data.get(field_name, None)
-                    if isinstance(v, DBRef):
+                    if isinstance(v, LazyReference):
+                        # LazyReference inherits DBRef but should not be dereferenced here !
+                        continue
+                    elif isinstance(v, DBRef):
                         reference_map.setdefault(field.document_type, set()).add(v.id)
                     elif isinstance(v, (dict, SON)) and '_ref' in v:
                         reference_map.setdefault(get_document(v['_cls']), set()).add(v['_ref'].id)
@@ -110,6 +114,9 @@ class DeReference(object):
                             if isinstance(field_cls, (Document, TopLevelDocumentMetaclass)):
                                 key = field_cls
                             reference_map.setdefault(key, set()).update(refs)
+            elif isinstance(item, LazyReference):
+                # LazyReference inherits DBRef but should not be dereferenced here !
+                continue
             elif isinstance(item, DBRef):
                 reference_map.setdefault(item.collection, set()).add(item.id)
             elif isinstance(item, (dict, SON)) and '_ref' in item:
@@ -126,7 +133,12 @@ class DeReference(object):
         """
         object_map = {}
         for collection, dbrefs in self.reference_map.iteritems():
-            if hasattr(collection, 'objects'):  # We have a document class for the refs
+
+            # we use getattr instead of hasattr because as hasattr swallows any exception under python2
+            # so it could hide nasty things without raising exceptions (cfr bug #1688))
+            ref_document_cls_exists = (getattr(collection, 'objects', None) is not None)
+
+            if ref_document_cls_exists:
                 col_name = collection._get_collection_name()
                 refs = [dbref for dbref in dbrefs
                         if (col_name, dbref) not in object_map]
@@ -134,7 +146,7 @@ class DeReference(object):
                 for key, doc in references.iteritems():
                     object_map[(col_name, key)] = doc
             else:  # Generic reference: use the refs data to convert to document
-                if isinstance(doc_type, (ListField, DictField, MapField,)):
+                if isinstance(doc_type, (ListField, DictField, MapField)):
                     continue
 
                 refs = [dbref for dbref in dbrefs
@@ -230,7 +242,7 @@ class DeReference(object):
             elif isinstance(v, (dict, list, tuple)) and depth <= self.max_depth:
                 item_name = '%s.%s' % (name, k) if name else name
                 data[k] = self._attach_objects(v, depth - 1, instance=instance, name=item_name)
-            elif hasattr(v, 'id'):
+            elif isinstance(v, DBRef) and hasattr(v, 'id'):
                 data[k] = self.object_map.get((v.collection, v.id), v)
 
         if instance and name:

mongoengine/document.py

@@ -39,7 +39,7 @@ class InvalidCollectionError(Exception):
     pass
 
 
-class EmbeddedDocument(BaseDocument):
+class EmbeddedDocument(six.with_metaclass(DocumentMetaclass, 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
@@ -58,7 +58,12 @@ class EmbeddedDocument(BaseDocument):
     # The __metaclass__ attribute is removed by 2to3 when running with Python3
     # my_metaclass is defined so that metaclass can be queried in Python 2 & 3
     my_metaclass = DocumentMetaclass
-    __metaclass__ = DocumentMetaclass
+
+    # A generic embedded document doesn't have any immutable properties
+    # that describe it uniquely, hence it shouldn't be hashable. You can
+    # define your own __hash__ method on a subclass if you need your
+    # embedded documents to be hashable.
+    __hash__ = None
 
     def __init__(self, *args, **kwargs):
         super(EmbeddedDocument, self).__init__(*args, **kwargs)
@@ -89,7 +94,7 @@ class EmbeddedDocument(BaseDocument):
         self._instance.reload(*args, **kwargs)
 
 
-class Document(BaseDocument):
+class Document(six.with_metaclass(TopLevelDocumentMetaclass, 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.
@@ -144,7 +149,6 @@ class Document(BaseDocument):
     # The __metaclass__ attribute is removed by 2to3 when running with Python3
     # my_metaclass is defined so that metaclass can be queried in Python 2 & 3
     my_metaclass = TopLevelDocumentMetaclass
-    __metaclass__ = TopLevelDocumentMetaclass
 
     __slots__ = ('__objects',)
 
@@ -160,6 +164,15 @@ class Document(BaseDocument):
         """Set the primary key."""
         return setattr(self, self._meta['id_field'], value)
 
+    def __hash__(self):
+        """Return the hash based on the PK of this document. If it's new
+        and doesn't have a PK yet, return the default object hash instead.
+        """
+        if self.pk is None:
+            return super(BaseDocument, self).__hash__()
+        else:
+            return hash(self.pk)
+
     @classmethod
     def _get_db(cls):
         """Some Model using other db_alias"""
@@ -167,45 +180,66 @@ class Document(BaseDocument):
 
     @classmethod
     def _get_collection(cls):
-        """Returns the collection for the document."""
-        # TODO: use new get_collection() with PyMongo3 ?
+        """Return a PyMongo collection for the document."""
         if not hasattr(cls, '_collection') or cls._collection is None:
-            db = cls._get_db()
-            collection_name = cls._get_collection_name()
-            # Create collection as a capped collection if specified
-            if cls._meta.get('max_size') or cls._meta.get('max_documents'):
-                # Get max document limit and max byte size from meta
-                max_size = cls._meta.get('max_size') or 10 * 2 ** 20  # 10MB default
-                max_documents = cls._meta.get('max_documents')
-                # Round up to next 256 bytes as MongoDB would do it to avoid exception
-                if max_size % 256:
-                    max_size = (max_size // 256 + 1) * 256
 
-                if collection_name in db.collection_names():
-                    cls._collection = db[collection_name]
-                    # The collection already exists, check if its capped
-                    # options match the specified capped options
-                    options = cls._collection.options()
-                    if options.get('max') != max_documents or \
-                            options.get('size') != max_size:
-                        msg = (('Cannot create collection "%s" as a capped '
-                                'collection as it already exists')
-                               % cls._collection)
-                        raise InvalidCollectionError(msg)
-                else:
-                    # Create the collection as a capped collection
-                    opts = {'capped': True, 'size': max_size}
-                    if max_documents:
-                        opts['max'] = max_documents
-                    cls._collection = db.create_collection(
-                        collection_name, **opts
-                    )
+            # Get the collection, either capped or regular.
+            if cls._meta.get('max_size') or cls._meta.get('max_documents'):
+                cls._collection = cls._get_capped_collection()
             else:
+                db = cls._get_db()
+                collection_name = cls._get_collection_name()
                 cls._collection = db[collection_name]
-            if cls._meta.get('auto_create_index', True):
+
+            # Ensure indexes on the collection unless auto_create_index was
+            # set to False.
+            # Also there is no need to ensure indexes on slave.
+            db = cls._get_db()
+            if cls._meta.get('auto_create_index', True) and\
+                    db.client.is_primary:
                 cls.ensure_indexes()
+
         return cls._collection
 
+    @classmethod
+    def _get_capped_collection(cls):
+        """Create a new or get an existing capped PyMongo collection."""
+        db = cls._get_db()
+        collection_name = cls._get_collection_name()
+
+        # Get max document limit and max byte size from meta.
+        max_size = cls._meta.get('max_size') or 10 * 2 ** 20  # 10MB default
+        max_documents = cls._meta.get('max_documents')
+
+        # MongoDB will automatically raise the size to make it a multiple of
+        # 256 bytes. We raise it here ourselves to be able to reliably compare
+        # the options below.
+        if max_size % 256:
+            max_size = (max_size // 256 + 1) * 256
+
+        # If the collection already exists and has different options
+        # (i.e. isn't capped or has different max/size), raise an error.
+        if collection_name in db.collection_names():
+            collection = db[collection_name]
+            options = collection.options()
+            if (
+                options.get('max') != max_documents or
+                options.get('size') != max_size
+            ):
+                raise InvalidCollectionError(
+                    'Cannot create collection "{}" as a capped '
+                    'collection as it already exists'.format(cls._collection)
+                )
+
+            return collection
+
+        # Create a new capped collection.
+        opts = {'capped': True, 'size': max_size}
+        if max_documents:
+            opts['max'] = max_documents
+
+        return db.create_collection(collection_name, **opts)
+
     def to_mongo(self, *args, **kwargs):
         data = super(Document, self).to_mongo(*args, **kwargs)
 
@@ -247,6 +281,9 @@ class Document(BaseDocument):
         elif query[id_field] != self.pk:
             raise InvalidQueryError('Invalid document modify query: it must modify only this document.')
 
+        # Need to add shard key to query, or you get an error
+        query.update(self._object_key)
+
         updated = self._qs(**query).modify(new=True, **update)
         if updated is None:
             return False
@@ -267,7 +304,7 @@ class Document(BaseDocument):
         created.
 
         :param force_insert: only try to create a new document, don't allow
-            updates of existing documents
+            updates of existing documents.
         :param validate: validates the document; set to ``False`` to skip.
         :param clean: call the document clean method, requires `validate` to be
             True.
@@ -287,7 +324,7 @@ class Document(BaseDocument):
         :param save_condition: only perform save if matching record in db
             satisfies condition(s) (e.g. version number).
             Raises :class:`OperationError` if the conditions are not satisfied
-        :parm signal_kwargs: (optional) kwargs dictionary to be passed to
+        :param signal_kwargs: (optional) kwargs dictionary to be passed to
             the signal calls.
 
         .. versionchanged:: 0.5
@@ -313,6 +350,9 @@ class Document(BaseDocument):
         .. versionchanged:: 0.10.7
             Add signal_kwargs argument
         """
+        if self._meta.get('abstract'):
+            raise InvalidDocumentError('Cannot save an abstract document.')
+
         signal_kwargs = signal_kwargs or {}
         signals.pre_save.send(self.__class__, document=self, **signal_kwargs)
 
@@ -329,68 +369,20 @@ class Document(BaseDocument):
         signals.pre_save_post_validation.send(self.__class__, document=self,
                                               created=created, **signal_kwargs)
 
+        if self._meta.get('auto_create_index', True):
+            self.ensure_indexes()
+
         try:
-            collection = self._get_collection()
-            if self._meta.get('auto_create_index', True):
-                self.ensure_indexes()
+            # Save a new document or update an existing one
             if created:
-                if force_insert:
-                    object_id = collection.insert(doc, **write_concern)
-                else:
-                    object_id = collection.save(doc, **write_concern)
-                    # In PyMongo 3.0, the save() call calls internally the _update() call
-                    # but they forget to return the _id value passed back, therefore getting it back here
-                    # Correct behaviour in 2.X and in 3.0.1+ versions
-                    if not object_id and pymongo.version_tuple == (3, 0):
-                        pk_as_mongo_obj = self._fields.get(self._meta['id_field']).to_mongo(self.pk)
-                        object_id = (
-                            self._qs.filter(pk=pk_as_mongo_obj).first() and
-                            self._qs.filter(pk=pk_as_mongo_obj).first().pk
-                        )  # TODO doesn't this make 2 queries?
+                object_id = self._save_create(doc, force_insert, write_concern)
             else:
-                object_id = doc['_id']
-                updates, removals = self._delta()
-                # Need to add shard key to query, or you get an error
-                if save_condition is not None:
-                    select_dict = transform.query(self.__class__,
-                                                  **save_condition)
-                else:
-                    select_dict = {}
-                select_dict['_id'] = object_id
-                shard_key = self._meta.get('shard_key', tuple())
-                for k in shard_key:
-                    path = self._lookup_field(k.split('.'))
-                    actual_key = [p.db_field for p in path]
-                    val = doc
-                    for ak in actual_key:
-                        val = val[ak]
-                    select_dict['.'.join(actual_key)] = val
-
-                def is_new_object(last_error):
-                    if last_error is not None:
-                        updated = last_error.get('updatedExisting')
-                        if updated is not None:
-                            return not updated
-                    return created
-
-                update_query = {}
-
-                if updates:
-                    update_query['$set'] = updates
-                if removals:
-                    update_query['$unset'] = removals
-                if updates or removals:
-                    upsert = save_condition is None
-                    last_error = collection.update(select_dict, update_query,
-                                                   upsert=upsert, **write_concern)
-                    if not upsert and last_error['n'] == 0:
-                        raise SaveConditionError('Race condition preventing'
-                                                 ' document update detected')
-                    created = is_new_object(last_error)
+                object_id, created = self._save_update(doc, save_condition,
+                                                       write_concern)
 
             if cascade is None:
-                cascade = self._meta.get(
-                    'cascade', False) or cascade_kwargs is not None
+                cascade = (self._meta.get('cascade', False) or
+                           cascade_kwargs is not None)
 
             if cascade:
                 kwargs = {
@@ -403,6 +395,7 @@ class Document(BaseDocument):
                     kwargs.update(cascade_kwargs)
                 kwargs['_refs'] = _refs
                 self.cascade_save(**kwargs)
+
         except pymongo.errors.DuplicateKeyError as err:
             message = u'Tried to save duplicate unique keys (%s)'
             raise NotUniqueError(message % six.text_type(err))
@@ -415,16 +408,101 @@ class Document(BaseDocument):
                 raise NotUniqueError(message % six.text_type(err))
             raise OperationError(message % six.text_type(err))
 
+        # Make sure we store the PK on this document now that it's saved
         id_field = self._meta['id_field']
         if created or id_field not in self._meta.get('shard_key', []):
             self[id_field] = self._fields[id_field].to_python(object_id)
 
         signals.post_save.send(self.__class__, document=self,
                                created=created, **signal_kwargs)
+
         self._clear_changed_fields()
         self._created = False
+
         return self
 
+    def _save_create(self, doc, force_insert, write_concern):
+        """Save a new document.
+
+        Helper method, should only be used inside save().
+        """
+        collection = self._get_collection()
+
+        if force_insert:
+            return collection.insert(doc, **write_concern)
+
+        object_id = collection.save(doc, **write_concern)
+
+        # In PyMongo 3.0, the save() call calls internally the _update() call
+        # but they forget to return the _id value passed back, therefore getting it back here
+        # Correct behaviour in 2.X and in 3.0.1+ versions
+        if not object_id and pymongo.version_tuple == (3, 0):
+            pk_as_mongo_obj = self._fields.get(self._meta['id_field']).to_mongo(self.pk)
+            object_id = (
+                self._qs.filter(pk=pk_as_mongo_obj).first() and
+                self._qs.filter(pk=pk_as_mongo_obj).first().pk
+            )  # TODO doesn't this make 2 queries?
+
+        return object_id
+
+    def _get_update_doc(self):
+        """Return a dict containing all the $set and $unset operations
+        that should be sent to MongoDB based on the changes made to this
+        Document.
+        """
+        updates, removals = self._delta()
+
+        update_doc = {}
+        if updates:
+            update_doc['$set'] = updates
+        if removals:
+            update_doc['$unset'] = removals
+
+        return update_doc
+
+    def _save_update(self, doc, save_condition, write_concern):
+        """Update an existing document.
+
+        Helper method, should only be used inside save().
+        """
+        collection = self._get_collection()
+        object_id = doc['_id']
+        created = False
+
+        select_dict = {}
+        if save_condition is not None:
+            select_dict = transform.query(self.__class__, **save_condition)
+
+        select_dict['_id'] = object_id
+
+        # Need to add shard key to query, or you get an error
+        shard_key = self._meta.get('shard_key', tuple())
+        for k in shard_key:
+            path = self._lookup_field(k.split('.'))
+            actual_key = [p.db_field for p in path]
+            val = doc
+            for ak in actual_key:
+                val = val[ak]
+            select_dict['.'.join(actual_key)] = val
+
+        update_doc = self._get_update_doc()
+        if update_doc:
+            upsert = save_condition is None
+            last_error = collection.update(select_dict, update_doc,
+                                           upsert=upsert, **write_concern)
+            if not upsert and last_error['n'] == 0:
+                raise SaveConditionError('Race condition preventing'
+                                         ' document update detected')
+            if last_error is not None:
+                updated_existing = last_error.get('updatedExisting')
+                if updated_existing is False:
+                    created = True
+                    # !!! This is bad, means we accidentally created a new,
+                    # potentially corrupted document. See
+                    # https://github.com/MongoEngine/mongoengine/issues/564
+
+        return object_id, created
+
     def cascade_save(self, **kwargs):
         """Recursively save any references and generic references on the
         document.
@@ -502,12 +580,11 @@ class Document(BaseDocument):
         """Delete the :class:`~mongoengine.Document` from the database. This
         will only take effect if the document has been previously saved.
 
-        :parm signal_kwargs: (optional) kwargs dictionary to be passed to
+        :param signal_kwargs: (optional) kwargs dictionary to be passed to
             the signal calls.
         :param write_concern: Extra keyword arguments are passed down which
-            will be used as options for the resultant
-            ``getLastError`` command.  For example,
-            ``save(..., write_concern={w: 2, fsync: True}, ...)`` will
+            will be used as options for the resultant ``getLastError`` command.
+            For example, ``save(..., w: 2, fsync: True)`` will
             wait until at least two servers have recorded the write and
             will force an fsync on the primary server.
 
@@ -628,7 +705,6 @@ class Document(BaseDocument):
             obj = obj[0]
         else:
             raise self.DoesNotExist('Document does not exist')
-
         for field in obj._data:
             if not fields or field in fields:
                 try:
@@ -636,7 +712,7 @@ class Document(BaseDocument):
                 except (KeyError, AttributeError):
                     try:
                         # If field is a special field, e.g. items is stored as _reserved_items,
-                        # an KeyError is thrown. So try to retrieve the field from _data
+                        # a KeyError is thrown. So try to retrieve the field from _data
                         setattr(self, field, self._reload(field, obj._data.get(field)))
                     except KeyError:
                         # If field is removed from the database while the object
@@ -644,7 +720,9 @@ class Document(BaseDocument):
                         # i.e. obj.update(unset__field=1) followed by obj.reload()
                         delattr(self, field)
 
-        self._changed_fields = obj._changed_fields
+        self._changed_fields = list(
+            set(self._changed_fields) - set(fields)
+        ) if fields else obj._changed_fields
         self._created = False
         return self
 
@@ -828,7 +906,6 @@ class Document(BaseDocument):
         """ Lists all of the indexes that should be created for given
         collection. It includes all the indexes from super- and sub-classes.
         """
-
         if cls._meta.get('abstract'):
             return []
 
@@ -891,8 +968,16 @@ class Document(BaseDocument):
         """
 
         required = cls.list_indexes()
-        existing = [info['key']
-                    for info in cls._get_collection().index_information().values()]
+
+        existing = []
+        for info in cls._get_collection().index_information().values():
+            if '_fts' in info['key'][0]:
+                index_type = info['key'][0][1]
+                text_index_fields = info.get('weights').keys()
+                existing.append(
+                    [(key, index_type) for key in text_index_fields])
+            else:
+                existing.append(info['key'])
         missing = [index for index in required if index not in existing]
         extra = [index for index in existing if index not in required]
 
@@ -909,10 +994,10 @@ class Document(BaseDocument):
         return {'missing': missing, 'extra': extra}
 
 
-class DynamicDocument(Document):
+class DynamicDocument(six.with_metaclass(TopLevelDocumentMetaclass, Document)):
     """A Dynamic Document class allowing flexible, expandable and uncontrolled
     schemas.  As a :class:`~mongoengine.Document` subclass, acts in the same
-    way as an ordinary document but has expando style properties.  Any data
+    way as an ordinary document but has expanded style properties.  Any data
     passed or set against the :class:`~mongoengine.DynamicDocument` that is
     not a field is automatically converted into a
     :class:`~mongoengine.fields.DynamicField` and data can be attributed to that
@@ -926,7 +1011,6 @@ class DynamicDocument(Document):
     # The __metaclass__ attribute is removed by 2to3 when running with Python3
     # my_metaclass is defined so that metaclass can be queried in Python 2 & 3
     my_metaclass = TopLevelDocumentMetaclass
-    __metaclass__ = TopLevelDocumentMetaclass
 
     _dynamic = True
 
@@ -937,11 +1021,12 @@ class DynamicDocument(Document):
         field_name = args[0]
         if field_name in self._dynamic_fields:
             setattr(self, field_name, None)
+            self._dynamic_fields[field_name].null = False
         else:
             super(DynamicDocument, self).__delattr__(*args, **kwargs)
 
 
-class DynamicEmbeddedDocument(EmbeddedDocument):
+class DynamicEmbeddedDocument(six.with_metaclass(DocumentMetaclass, EmbeddedDocument)):
     """A Dynamic Embedded Document class allowing flexible, expandable and
     uncontrolled schemas. See :class:`~mongoengine.DynamicDocument` for more
     information about dynamic documents.
@@ -950,7 +1035,6 @@ class DynamicEmbeddedDocument(EmbeddedDocument):
     # The __metaclass__ attribute is removed by 2to3 when running with Python3
     # my_metaclass is defined so that metaclass can be queried in Python 2 & 3
     my_metaclass = DocumentMetaclass
-    __metaclass__ = DocumentMetaclass
 
     _dynamic = True
 

mongoengine/errors.py

@@ -50,8 +50,8 @@ class FieldDoesNotExist(Exception):
     or an :class:`~mongoengine.EmbeddedDocument`.
 
     To avoid this behavior on data loading,
-    you should the :attr:`strict` to ``False``
-    in the :attr:`meta` dictionnary.
+    you should set the :attr:`strict` to ``False``
+    in the :attr:`meta` dictionary.
     """
 
 

mongoengine/fields.py

@@ -2,9 +2,9 @@ import datetime
 import decimal
 import itertools
 import re
+import socket
 import time
 import uuid
-import warnings
 from operator import itemgetter
 
 from bson import Binary, DBRef, ObjectId, SON
@@ -24,11 +24,15 @@ try:
 except ImportError:
     Int64 = long
 
+
 from mongoengine.base import (BaseDocument, BaseField, ComplexBaseField,
-                              GeoJsonBaseField, ObjectIdField, get_document)
+                              GeoJsonBaseField, LazyReference, ObjectIdField,
+                              get_document)
+from mongoengine.base.utils import LazyRegexCompiler
+from mongoengine.common import _import_class
 from mongoengine.connection import DEFAULT_CONNECTION_NAME, get_db
 from mongoengine.document import Document, EmbeddedDocument
-from mongoengine.errors import DoesNotExist, ValidationError
+from mongoengine.errors import DoesNotExist, InvalidQueryError, ValidationError
 from mongoengine.python_support import StringIO
 from mongoengine.queryset import DO_NOTHING, QuerySet
 
@@ -38,13 +42,20 @@ except ImportError:
     Image = None
     ImageOps = None
 
+if six.PY3:
+    # Useless as long as 2to3 gets executed
+    # as it turns `long` into `int` blindly
+    long = int
+
+
 __all__ = (
     'StringField', 'URLField', 'EmailField', 'IntField', 'LongField',
-    'FloatField', 'DecimalField', 'BooleanField', 'DateTimeField',
+    'FloatField', 'DecimalField', 'BooleanField', 'DateTimeField', 'DateField',
     'ComplexDateTimeField', 'EmbeddedDocumentField', 'ObjectIdField',
     'GenericEmbeddedDocumentField', 'DynamicField', 'ListField',
     'SortedListField', 'EmbeddedDocumentListField', 'DictField',
     'MapField', 'ReferenceField', 'CachedReferenceField',
+    'LazyReferenceField', 'GenericLazyReferenceField',
     'GenericReferenceField', 'BinaryField', 'GridFSError', 'GridFSProxy',
     'FileField', 'ImageGridFsProxy', 'ImproperlyConfigured', 'ImageField',
     'GeoPointField', 'PointField', 'LineStringField', 'PolygonField',
@@ -119,7 +130,7 @@ class URLField(StringField):
     .. versionadded:: 0.3
     """
 
-    _URL_REGEX = re.compile(
+    _URL_REGEX = LazyRegexCompiler(
         r'^(?:[a-z0-9\.\-]*)://'  # scheme is validated separately
         r'(?:(?:[A-Z0-9](?:[A-Z0-9-_]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}\.?|[A-Z0-9-]{2,}(?<!-)\.?)|'  # domain...
         r'localhost|'  # localhost...
@@ -139,12 +150,12 @@ class URLField(StringField):
         # Check first if the scheme is valid
         scheme = value.split('://')[0].lower()
         if scheme not in self.schemes:
-            self.error('Invalid scheme {} in URL: {}'.format(scheme, value))
+            self.error(u'Invalid scheme {} in URL: {}'.format(scheme, value))
             return
 
         # Then check full URL
         if not self.url_regex.match(value):
-            self.error('Invalid URL: {}'.format(value))
+            self.error(u'Invalid URL: {}'.format(value))
             return
 
 
@@ -153,21 +164,105 @@ class EmailField(StringField):
 
     .. versionadded:: 0.4
     """
-
-    EMAIL_REGEX = re.compile(
-        # dot-atom
-        r"(^[-!#$%&'*+/=?^_`{}|~0-9A-Z]+(\.[-!#$%&'*+/=?^_`{}|~0-9A-Z]+)*"
-        # quoted-string
-        r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-011\013\014\016-\177])*"'
-        # domain (max length of an ICAAN TLD is 22 characters)
-        r')@(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}|[A-Z0-9-]{2,}(?<!-))$', re.IGNORECASE
+    USER_REGEX = LazyRegexCompiler(
+        # `dot-atom` defined in RFC 5322 Section 3.2.3.
+        r"(^[-!#$%&'*+/=?^_`{}|~0-9A-Z]+(\.[-!#$%&'*+/=?^_`{}|~0-9A-Z]+)*\Z"
+        # `quoted-string` defined in RFC 5322 Section 3.2.4.
+        r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-\011\013\014\016-\177])*"\Z)',
+        re.IGNORECASE
     )
 
+    UTF8_USER_REGEX = LazyRegexCompiler(
+        six.u(
+            # RFC 6531 Section 3.3 extends `atext` (used by dot-atom) to
+            # include `UTF8-non-ascii`.
+            r"(^[-!#$%&'*+/=?^_`{}|~0-9A-Z\u0080-\U0010FFFF]+(\.[-!#$%&'*+/=?^_`{}|~0-9A-Z\u0080-\U0010FFFF]+)*\Z"
+            # `quoted-string`
+            r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-\011\013\014\016-\177])*"\Z)'
+        ), re.IGNORECASE | re.UNICODE
+    )
+
+    DOMAIN_REGEX = LazyRegexCompiler(
+        r'((?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+)(?:[A-Z0-9-]{2,63}(?<!-))\Z',
+        re.IGNORECASE
+    )
+
+    error_msg = u'Invalid email address: %s'
+
+    def __init__(self, domain_whitelist=None, allow_utf8_user=False,
+                 allow_ip_domain=False, *args, **kwargs):
+        """Initialize the EmailField.
+
+        Args:
+            domain_whitelist (list) - list of otherwise invalid domain
+                                      names which you'd like to support.
+            allow_utf8_user (bool) - if True, the user part of the email
+                                     address can contain UTF8 characters.
+                                     False by default.
+            allow_ip_domain (bool) - if True, the domain part of the email
+                                     can be a valid IPv4 or IPv6 address.
+        """
+        self.domain_whitelist = domain_whitelist or []
+        self.allow_utf8_user = allow_utf8_user
+        self.allow_ip_domain = allow_ip_domain
+        super(EmailField, self).__init__(*args, **kwargs)
+
+    def validate_user_part(self, user_part):
+        """Validate the user part of the email address. Return True if
+        valid and False otherwise.
+        """
+        if self.allow_utf8_user:
+            return self.UTF8_USER_REGEX.match(user_part)
+        return self.USER_REGEX.match(user_part)
+
+    def validate_domain_part(self, domain_part):
+        """Validate the domain part of the email address. Return True if
+        valid and False otherwise.
+        """
+        # Skip domain validation if it's in the whitelist.
+        if domain_part in self.domain_whitelist:
+            return True
+
+        if self.DOMAIN_REGEX.match(domain_part):
+            return True
+
+        # Validate IPv4/IPv6, e.g. user@[192.168.0.1]
+        if (
+            self.allow_ip_domain and
+            domain_part[0] == '[' and
+            domain_part[-1] == ']'
+        ):
+            for addr_family in (socket.AF_INET, socket.AF_INET6):
+                try:
+                    socket.inet_pton(addr_family, domain_part[1:-1])
+                    return True
+                except (socket.error, UnicodeEncodeError):
+                    pass
+
+        return False
+
     def validate(self, value):
-        if not EmailField.EMAIL_REGEX.match(value):
-            self.error('Invalid email address: %s' % value)
         super(EmailField, self).validate(value)
 
+        if '@' not in value:
+            self.error(self.error_msg % value)
+
+        user_part, domain_part = value.rsplit('@', 1)
+
+        # Validate the user part.
+        if not self.validate_user_part(user_part):
+            self.error(self.error_msg % value)
+
+        # Validate the domain and, if invalid, see if it's IDN-encoded.
+        if not self.validate_domain_part(domain_part):
+            try:
+                domain_part = domain_part.encode('idna').decode('ascii')
+            except UnicodeError:
+                self.error(self.error_msg % value)
+            else:
+                if not self.validate_domain_part(domain_part):
+                    self.error(self.error_msg % value)
+
 
 class IntField(BaseField):
     """32-bit integer field."""
@@ -276,7 +371,8 @@ class FloatField(BaseField):
 
 
 class DecimalField(BaseField):
-    """Fixed-point decimal number field.
+    """Fixed-point decimal number field. Stores the value as a float by default unless `force_string` is used.
+    If using floats, beware of Decimal to float conversion (potential precision loss)
 
     .. versionchanged:: 0.8
     .. versionadded:: 0.3
@@ -287,7 +383,9 @@ class DecimalField(BaseField):
         """
         :param min_value: Validation rule for the minimum acceptable value.
         :param max_value: Validation rule for the maximum acceptable value.
-        :param force_string: Store as a string.
+        :param force_string: Store the value as a string (instead of a float).
+         Be aware that this affects query sorting and operation like lte, gte (as string comparison is applied)
+         and some query operator won't work (e.g: inc, dec)
         :param precision: Number of decimal places to store.
         :param rounding: The rounding rule from the python decimal library:
 
@@ -374,6 +472,8 @@ class DateTimeField(BaseField):
     installed you can utilise it to convert varying types of date formats into valid
     python datetime objects.
 
+    Note: To default the field to the current datetime, use: DateTimeField(default=datetime.utcnow)
+
     Note: Microseconds are rounded to the nearest millisecond.
       Pre UTC microsecond support is effectively broken.
       Use :class:`~mongoengine.fields.ComplexDateTimeField` if you
@@ -398,6 +498,10 @@ class DateTimeField(BaseField):
         if not isinstance(value, six.string_types):
             return None
 
+        value = value.strip()
+        if not value:
+            return None
+
         # Attempt to parse a datetime:
         if dateutil:
             try:
@@ -433,6 +537,22 @@ class DateTimeField(BaseField):
         return super(DateTimeField, self).prepare_query_value(op, self.to_mongo(value))
 
 
+class DateField(DateTimeField):
+    def to_mongo(self, value):
+        value = super(DateField, self).to_mongo(value)
+        # drop hours, minutes, seconds
+        if isinstance(value, datetime.datetime):
+            value = datetime.datetime(value.year, value.month, value.day)
+        return value
+
+    def to_python(self, value):
+        value = super(DateField, self).to_python(value)
+        # convert datetime to date
+        if isinstance(value, datetime.datetime):
+            value = datetime.date(value.year, value.month, value.day)
+        return value
+
+
 class ComplexDateTimeField(StringField):
     """
     ComplexDateTimeField handles microseconds exactly instead of rounding
@@ -449,11 +569,15 @@ class ComplexDateTimeField(StringField):
     The `,` as the separator can be easily modified by passing the `separator`
     keyword when initializing the field.
 
+    Note: To default the field to the current datetime, use: DateTimeField(default=datetime.utcnow)
+
     .. versionadded:: 0.5
     """
 
     def __init__(self, separator=',', **kwargs):
-        self.names = ['year', 'month', 'day', 'hour', 'minute', 'second', 'microsecond']
+        """
+        :param separator: Allows to customize the separator used for storage (default ``,``)
+        """
         self.separator = separator
         self.format = separator.join(['%Y', '%m', '%d', '%H', '%M', '%S', '%f'])
         super(ComplexDateTimeField, self).__init__(**kwargs)
@@ -480,20 +604,24 @@ class ComplexDateTimeField(StringField):
         >>> ComplexDateTimeField()._convert_from_string(a)
         datetime.datetime(2011, 6, 8, 20, 26, 24, 92284)
         """
-        values = map(int, data.split(self.separator))
+        values = [int(d) for d in data.split(self.separator)]
         return datetime.datetime(*values)
 
     def __get__(self, instance, owner):
+        if instance is None:
+            return self
+
         data = super(ComplexDateTimeField, self).__get__(instance, owner)
-        if data is None:
-            return None if self.null else datetime.datetime.now()
-        if isinstance(data, datetime.datetime):
+
+        if isinstance(data, datetime.datetime) or data is None:
             return data
         return self._convert_from_string(data)
 
     def __set__(self, instance, value):
-        value = self._convert_from_datetime(value) if value else value
-        return super(ComplexDateTimeField, self).__set__(instance, value)
+        super(ComplexDateTimeField, self).__set__(instance, value)
+        value = instance._data[self.name]
+        if value is not None:
+            instance._data[self.name] = self._convert_from_datetime(value)
 
     def validate(self, value):
         value = self.to_python(value)
@@ -522,9 +650,10 @@ class EmbeddedDocumentField(BaseField):
     """
 
     def __init__(self, document_type, **kwargs):
-        if (
-            not isinstance(document_type, six.string_types) and
-            not issubclass(document_type, EmbeddedDocument)
+        # XXX ValidationError raised outside of the "validate" method.
+        if not (
+            isinstance(document_type, six.string_types) or
+            issubclass(document_type, EmbeddedDocument)
         ):
             self.error('Invalid embedded document class provided to an '
                        'EmbeddedDocumentField')
@@ -536,9 +665,17 @@ class EmbeddedDocumentField(BaseField):
     def document_type(self):
         if isinstance(self.document_type_obj, six.string_types):
             if self.document_type_obj == RECURSIVE_REFERENCE_CONSTANT:
-                self.document_type_obj = self.owner_document
+                resolved_document_type = self.owner_document
             else:
-                self.document_type_obj = get_document(self.document_type_obj)
+                resolved_document_type = get_document(self.document_type_obj)
+
+            if not issubclass(resolved_document_type, EmbeddedDocument):
+                # Due to the late resolution of the document_type
+                # There is a chance that it won't be an EmbeddedDocument (#1661)
+                self.error('Invalid embedded document class provided to an '
+                           'EmbeddedDocumentField')
+            self.document_type_obj = resolved_document_type
+
         return self.document_type_obj
 
     def to_python(self, value):
@@ -566,7 +703,11 @@ class EmbeddedDocumentField(BaseField):
 
     def prepare_query_value(self, op, value):
         if value is not None and not isinstance(value, self.document_type):
-            value = self.document_type._from_son(value)
+            try:
+                value = self.document_type._from_son(value)
+            except ValueError:
+                raise InvalidQueryError("Querying the embedded document '%s' failed, due to an invalid query value" %
+                                        (self.document_type._class_name,))
         super(EmbeddedDocumentField, self).prepare_query_value(op, value)
         return self.to_mongo(value)
 
@@ -593,16 +734,28 @@ class GenericEmbeddedDocumentField(BaseField):
         return value
 
     def validate(self, value, clean=True):
+        if self.choices and isinstance(value, SON):
+            for choice in self.choices:
+                if value['_cls'] == choice._class_name:
+                    return True
+
         if not isinstance(value, EmbeddedDocument):
             self.error('Invalid embedded document instance provided to an '
                        'GenericEmbeddedDocumentField')
 
         value.validate(clean=clean)
 
+    def lookup_member(self, member_name):
+        if self.choices:
+            for choice in self.choices:
+                field = choice._fields.get(member_name)
+                if field:
+                    return field
+        return None
+
     def to_mongo(self, document, use_db_field=True, fields=None):
         if document is None:
             return None
-
         data = document.to_mongo(use_db_field, fields)
         if '_cls' not in data:
             data['_cls'] = document._class_name
@@ -686,6 +839,17 @@ class ListField(ComplexBaseField):
         kwargs.setdefault('default', lambda: [])
         super(ListField, self).__init__(**kwargs)
 
+    def __get__(self, instance, owner):
+        if instance is None:
+            # Document class being used rather than a document object
+            return self
+        value = instance._data.get(self.name)
+        LazyReferenceField = _import_class('LazyReferenceField')
+        GenericLazyReferenceField = _import_class('GenericLazyReferenceField')
+        if isinstance(self.field, (LazyReferenceField, GenericLazyReferenceField)) and value:
+            instance._data[self.name] = [self.field.build_lazyref(x) for x in value]
+        return super(ListField, self).__get__(instance, owner)
+
     def validate(self, value):
         """Make sure that a list of valid fields is being used."""
         if (not isinstance(value, (list, tuple, QuerySet)) or
@@ -796,12 +960,10 @@ class DictField(ComplexBaseField):
     .. versionchanged:: 0.5 - Can now handle complex / varying types of data
     """
 
-    def __init__(self, basecls=None, field=None, *args, **kwargs):
+    def __init__(self, field=None, *args, **kwargs):
         self.field = field
         self._auto_dereference = False
-        self.basecls = basecls or BaseField
-        if not issubclass(self.basecls, BaseField):
-            self.error('DictField only accepts dict values')
+
         kwargs.setdefault('default', lambda: {})
         super(DictField, self).__init__(*args, **kwargs)
 
@@ -820,7 +982,7 @@ class DictField(ComplexBaseField):
         super(DictField, self).validate(value)
 
     def lookup_member(self, member_name):
-        return DictField(basecls=self.basecls, db_field=member_name)
+        return DictField(db_field=member_name)
 
     def prepare_query_value(self, op, value):
         match_operators = ['contains', 'icontains', 'startswith',
@@ -850,6 +1012,7 @@ class MapField(DictField):
     """
 
     def __init__(self, field=None, *args, **kwargs):
+        # XXX ValidationError raised outside of the "validate" method.
         if not isinstance(field, BaseField):
             self.error('Argument to MapField constructor must be a valid '
                        'field')
@@ -860,6 +1023,15 @@ class ReferenceField(BaseField):
     """A reference to a document that will be automatically dereferenced on
     access (lazily).
 
+    Note this means you will get a database I/O access everytime you access
+    this field. This is necessary because the field returns a :class:`~mongoengine.Document`
+    which precise type can depend of the value of the `_cls` field present in the
+    document in database.
+    In short, using this type of field can lead to poor performances (especially
+    if you access this field only to retrieve it `pk` field which is already
+    known before dereference). To solve this you should consider using the
+    :class:`~mongoengine.fields.LazyReferenceField`.
+
     Use the `reverse_delete_rule` to handle what should happen if the document
     the field is referencing is deleted.  EmbeddedDocuments, DictFields and
     MapFields does not support reverse_delete_rule and an `InvalidDocumentError`
@@ -878,15 +1050,13 @@ class ReferenceField(BaseField):
 
     .. code-block:: python
 
-        class Bar(Document):
-            content = StringField()
-            foo = ReferenceField('Foo')
+        class Org(Document):
+            owner = ReferenceField('User')
 
-        Foo.register_delete_rule(Bar, 'foo', NULLIFY)
+        class User(Document):
+            org = ReferenceField('Org', reverse_delete_rule=CASCADE)
 
-    .. note ::
-        `reverse_delete_rule` does not trigger pre / post delete signals to be
-        triggered.
+        User.register_delete_rule(Org, 'owner', DENY)
 
     .. versionchanged:: 0.5 added `reverse_delete_rule`
     """
@@ -904,6 +1074,7 @@ class ReferenceField(BaseField):
             A reference to an abstract document type is always stored as a
             :class:`~pymongo.dbref.DBRef`, regardless of the value of `dbref`.
         """
+        # XXX ValidationError raised outside of the "validate" method.
         if (
             not isinstance(document_type, six.string_types) and
             not issubclass(document_type, Document)
@@ -958,6 +1129,8 @@ class ReferenceField(BaseField):
         if isinstance(document, Document):
             # We need the id from the saved object to create the DBRef
             id_ = document.pk
+
+            # XXX ValidationError raised outside of the "validate" method.
             if id_ is None:
                 self.error('You can only reference documents once they have'
                            ' been saved to the database')
@@ -997,19 +1170,20 @@ class ReferenceField(BaseField):
         return self.to_mongo(value)
 
     def validate(self, value):
-
-        if not isinstance(value, (self.document_type, DBRef)):
-            self.error('A ReferenceField only accepts DBRef or documents')
+        if not isinstance(value, (self.document_type, LazyReference, DBRef, ObjectId)):
+            self.error('A ReferenceField only accepts DBRef, LazyReference, ObjectId or documents')
 
         if isinstance(value, Document) and value.id is None:
             self.error('You can only reference documents once they have been '
                        'saved to the database')
 
-        if self.document_type._meta.get('abstract') and \
-                not isinstance(value, self.document_type):
+        if (
+            self.document_type._meta.get('abstract') and
+            not isinstance(value, self.document_type)
+        ):
             self.error(
                 '%s is not an instance of abstract reference type %s' % (
-                    self.document_type._class_name)
+                    value, self.document_type._class_name)
             )
 
     def lookup_member(self, member_name):
@@ -1032,6 +1206,7 @@ class CachedReferenceField(BaseField):
         if fields is None:
             fields = []
 
+        # XXX ValidationError raised outside of the "validate" method.
         if (
             not isinstance(document_type, six.string_types) and
             not issubclass(document_type, Document)
@@ -1106,6 +1281,7 @@ class CachedReferenceField(BaseField):
         id_field_name = self.document_type._meta['id_field']
         id_field = self.document_type._fields[id_field_name]
 
+        # XXX ValidationError raised outside of the "validate" method.
         if isinstance(document, Document):
             # We need the id from the saved object to create the DBRef
             id_ = document.pk
@@ -1114,7 +1290,6 @@ class CachedReferenceField(BaseField):
                            ' been saved to the database')
         else:
             self.error('Only accept a document object')
-            # TODO: should raise here or will fail next statement
 
         value = SON((
             ('_id', id_field.to_mongo(id_)),
@@ -1132,16 +1307,20 @@ class CachedReferenceField(BaseField):
         if value is None:
             return None
 
+        # XXX ValidationError raised outside of the "validate" method.
         if isinstance(value, Document):
             if value.pk is None:
                 self.error('You can only reference documents once they have'
                            ' been saved to the database')
-            return {'_id': value.pk}
+            value_dict = {'_id': value.pk}
+            for field in self.fields:
+                value_dict.update({field: value[field]})
+
+            return value_dict
 
         raise NotImplementedError
 
     def validate(self, value):
-
         if not isinstance(value, self.document_type):
             self.error('A CachedReferenceField only accepts documents')
 
@@ -1174,6 +1353,12 @@ class GenericReferenceField(BaseField):
     """A reference to *any* :class:`~mongoengine.document.Document` subclass
     that will be automatically dereferenced on access (lazily).
 
+    Note this field works the same way as :class:`~mongoengine.document.ReferenceField`,
+    doing database I/O access the first time it is accessed (even if it's to access
+    it ``pk`` or ``id`` field).
+    To solve this you should consider using the
+    :class:`~mongoengine.fields.GenericLazyReferenceField`.
+
     .. note ::
         * Any documents used as a generic reference must be registered in the
           document registry.  Importing the model will automatically register
@@ -1196,6 +1381,8 @@ class GenericReferenceField(BaseField):
                 elif isinstance(choice, type) and issubclass(choice, Document):
                     self.choices.append(choice._class_name)
                 else:
+                    # XXX ValidationError raised outside of the "validate"
+                    # method.
                     self.error('Invalid choices provided: must be a list of'
                                'Document subclasses and/or six.string_typess')
 
@@ -1259,6 +1446,7 @@ class GenericReferenceField(BaseField):
             # We need the id from the saved object to create the DBRef
             id_ = document.id
             if id_ is None:
+                # XXX ValidationError raised outside of the "validate" method.
                 self.error('You can only reference documents once they have'
                            ' been saved to the database')
         else:
@@ -1344,9 +1532,11 @@ class GridFSProxy(object):
     def __get__(self, instance, value):
         return self
 
-    def __nonzero__(self):
+    def __bool__(self):
         return bool(self.grid_id)
 
+    __nonzero__ = __bool__  # For Py2 support
+
     def __getstate__(self):
         self_dict = self.__dict__
         self_dict['_fs'] = None
@@ -1364,9 +1554,9 @@ class GridFSProxy(object):
         return '<%s: %s>' % (self.__class__.__name__, self.grid_id)
 
     def __str__(self):
-        name = getattr(
-            self.get(), 'filename', self.grid_id) if self.get() else '(no file)'
-        return '<%s: %s>' % (self.__class__.__name__, name)
+        gridout = self.get()
+        filename = getattr(gridout, 'filename') if gridout else '<no file>'
+        return '<%s: %s (%s)>' % (self.__class__.__name__, filename, self.grid_id)
 
     def __eq__(self, other):
         if isinstance(other, GridFSProxy):
@@ -1376,6 +1566,9 @@ class GridFSProxy(object):
         else:
             return False
 
+    def __ne__(self, other):
+        return not self == other
+
     @property
     def fs(self):
         if not self._fs:
@@ -2049,3 +2242,201 @@ class MultiPolygonField(GeoJsonBaseField):
     .. versionadded:: 0.9
     """
     _type = 'MultiPolygon'
+
+
+class LazyReferenceField(BaseField):
+    """A really lazy reference to a document.
+    Unlike the :class:`~mongoengine.fields.ReferenceField` it will
+    **not** be automatically (lazily) dereferenced on access.
+    Instead, access will return a :class:`~mongoengine.base.LazyReference` class
+    instance, allowing access to `pk` or manual dereference by using
+    ``fetch()`` method.
+
+    .. versionadded:: 0.15
+    """
+
+    def __init__(self, document_type, passthrough=False, dbref=False,
+                 reverse_delete_rule=DO_NOTHING, **kwargs):
+        """Initialises the Reference Field.
+
+        :param dbref:  Store the reference as :class:`~pymongo.dbref.DBRef`
+          or as the :class:`~pymongo.objectid.ObjectId`.id .
+        :param reverse_delete_rule: Determines what to do when the referring
+          object is deleted
+        :param passthrough: When trying to access unknown fields, the
+        :class:`~mongoengine.base.datastructure.LazyReference` instance will
+        automatically call `fetch()` and try to retrive the field on the fetched
+        document. Note this only work getting field (not setting or deleting).
+        """
+        # XXX ValidationError raised outside of the "validate" method.
+        if (
+            not isinstance(document_type, six.string_types) and
+            not issubclass(document_type, Document)
+        ):
+            self.error('Argument to LazyReferenceField constructor must be a '
+                       'document class or a string')
+
+        self.dbref = dbref
+        self.passthrough = passthrough
+        self.document_type_obj = document_type
+        self.reverse_delete_rule = reverse_delete_rule
+        super(LazyReferenceField, self).__init__(**kwargs)
+
+    @property
+    def document_type(self):
+        if isinstance(self.document_type_obj, six.string_types):
+            if self.document_type_obj == RECURSIVE_REFERENCE_CONSTANT:
+                self.document_type_obj = self.owner_document
+            else:
+                self.document_type_obj = get_document(self.document_type_obj)
+        return self.document_type_obj
+
+    def build_lazyref(self, value):
+        if isinstance(value, LazyReference):
+            if value.passthrough != self.passthrough:
+                value = LazyReference(value.document_type, value.pk, passthrough=self.passthrough)
+        elif value is not None:
+            if isinstance(value, self.document_type):
+                value = LazyReference(self.document_type, value.pk, passthrough=self.passthrough)
+            elif isinstance(value, DBRef):
+                value = LazyReference(self.document_type, value.id, passthrough=self.passthrough)
+            else:
+                # value is the primary key of the referenced document
+                value = LazyReference(self.document_type, value, passthrough=self.passthrough)
+        return value
+
+    def __get__(self, instance, owner):
+        """Descriptor to allow lazy dereferencing."""
+        if instance is None:
+            # Document class being used rather than a document object
+            return self
+
+        value = self.build_lazyref(instance._data.get(self.name))
+        if value:
+            instance._data[self.name] = value
+
+        return super(LazyReferenceField, self).__get__(instance, owner)
+
+    def to_mongo(self, value):
+        if isinstance(value, LazyReference):
+            pk = value.pk
+        elif isinstance(value, self.document_type):
+            pk = value.pk
+        elif isinstance(value, DBRef):
+            pk = value.id
+        else:
+            # value is the primary key of the referenced document
+            pk = value
+        id_field_name = self.document_type._meta['id_field']
+        id_field = self.document_type._fields[id_field_name]
+        pk = id_field.to_mongo(pk)
+        if self.dbref:
+            return DBRef(self.document_type._get_collection_name(), pk)
+        else:
+            return pk
+
+    def validate(self, value):
+        if isinstance(value, LazyReference):
+            if value.collection != self.document_type._get_collection_name():
+                self.error('Reference must be on a `%s` document.' % self.document_type)
+            pk = value.pk
+        elif isinstance(value, self.document_type):
+            pk = value.pk
+        elif isinstance(value, DBRef):
+            # TODO: check collection ?
+            collection = self.document_type._get_collection_name()
+            if value.collection != collection:
+                self.error("DBRef on bad collection (must be on `%s`)" % collection)
+            pk = value.id
+        else:
+            # value is the primary key of the referenced document
+            id_field_name = self.document_type._meta['id_field']
+            id_field = getattr(self.document_type, id_field_name)
+            pk = value
+            try:
+                id_field.validate(pk)
+            except ValidationError:
+                self.error(
+                    "value should be `{0}` document, LazyReference or DBRef on `{0}` "
+                    "or `{0}`'s primary key (i.e. `{1}`)".format(
+                        self.document_type.__name__, type(id_field).__name__))
+
+        if pk is None:
+            self.error('You can only reference documents once they have been '
+                       'saved to the database')
+
+    def prepare_query_value(self, op, value):
+        if value is None:
+            return None
+        super(LazyReferenceField, self).prepare_query_value(op, value)
+        return self.to_mongo(value)
+
+    def lookup_member(self, member_name):
+        return self.document_type._fields.get(member_name)
+
+
+class GenericLazyReferenceField(GenericReferenceField):
+    """A reference to *any* :class:`~mongoengine.document.Document` subclass.
+    Unlike the :class:`~mongoengine.fields.GenericReferenceField` it will
+    **not** be automatically (lazily) dereferenced on access.
+    Instead, access will return a :class:`~mongoengine.base.LazyReference` class
+    instance, allowing access to `pk` or manual dereference by using
+    ``fetch()`` method.
+
+    .. note ::
+        * Any documents used as a generic reference must be registered in the
+          document registry.  Importing the model will automatically register
+          it.
+
+        * You can use the choices param to limit the acceptable Document types
+
+    .. versionadded:: 0.15
+    """
+
+    def __init__(self, *args, **kwargs):
+        self.passthrough = kwargs.pop('passthrough', False)
+        super(GenericLazyReferenceField, self).__init__(*args, **kwargs)
+
+    def _validate_choices(self, value):
+        if isinstance(value, LazyReference):
+            value = value.document_type._class_name
+        super(GenericLazyReferenceField, self)._validate_choices(value)
+
+    def build_lazyref(self, value):
+        if isinstance(value, LazyReference):
+            if value.passthrough != self.passthrough:
+                value = LazyReference(value.document_type, value.pk, passthrough=self.passthrough)
+        elif value is not None:
+            if isinstance(value, (dict, SON)):
+                value = LazyReference(get_document(value['_cls']), value['_ref'].id, passthrough=self.passthrough)
+            elif isinstance(value, Document):
+                value = LazyReference(type(value), value.pk, passthrough=self.passthrough)
+        return value
+
+    def __get__(self, instance, owner):
+        if instance is None:
+            return self
+
+        value = self.build_lazyref(instance._data.get(self.name))
+        if value:
+            instance._data[self.name] = value
+
+        return super(GenericLazyReferenceField, self).__get__(instance, owner)
+
+    def validate(self, value):
+        if isinstance(value, LazyReference) and value.pk is None:
+            self.error('You can only reference documents once they have been'
+                       ' saved to the database')
+        return super(GenericLazyReferenceField, self).validate(value)
+
+    def to_mongo(self, document):
+        if document is None:
+            return None
+
+        if isinstance(document, LazyReference):
+            return SON((
+                ('_cls', document.document_type._class_name),
+                ('_ref', DBRef(document.document_type._get_collection_name(), document.pk))
+            ))
+        else:
+            return super(GenericLazyReferenceField, self).to_mongo(document)

mongoengine/python_support.py

@@ -6,11 +6,7 @@ import pymongo
 import six
 
 
-if pymongo.version_tuple[0] < 3:
-    IS_PYMONGO_3 = False
-else:
-    IS_PYMONGO_3 = True
-
+IS_PYMONGO_3 = pymongo.version_tuple[0] >= 3
 
 # six.BytesIO resolves to StringIO.StringIO in Py2 and io.BytesIO in Py3.
 StringIO = six.BytesIO

mongoengine/queryset/base.py

@@ -2,7 +2,6 @@ from __future__ import absolute_import
 
 import copy
 import itertools
-import operator
 import pprint
 import re
 import warnings
@@ -18,7 +17,7 @@ from mongoengine import signals
 from mongoengine.base import get_document
 from mongoengine.common import _import_class
 from mongoengine.connection import get_db
-from mongoengine.context_managers import switch_db
+from mongoengine.context_managers import set_write_concern, switch_db
 from mongoengine.errors import (InvalidQueryError, LookUpError,
                                 NotUniqueError, OperationError)
 from mongoengine.python_support import IS_PYMONGO_3
@@ -67,7 +66,6 @@ class BaseQuerySet(object):
         self._scalar = []
         self._none = False
         self._as_pymongo = False
-        self._as_pymongo_coerce = False
         self._search_text = None
 
         # If inheritance is allowed, only return instances and instances of
@@ -86,6 +84,7 @@ class BaseQuerySet(object):
         self._batch_size = None
         self.only_fields = []
         self._max_time_ms = None
+        self._comment = None
 
     def __call__(self, q_obj=None, class_check=True, read_preference=None,
                  **query):
@@ -157,44 +156,49 @@ class BaseQuerySet(object):
         # self._cursor
 
     def __getitem__(self, key):
-        """Support skip and limit using getitem and slicing syntax."""
+        """Return a document instance corresponding to a given index if
+        the key is an integer. If the key is a slice, translate its
+        bounds into a skip and a limit, and return a cloned queryset
+        with that skip/limit applied. For example:
+
+        >>> User.objects[0]
+        <User: User object>
+        >>> User.objects[1:3]
+        [<User: User object>, <User: User object>]
+        """
         queryset = self.clone()
 
-        # Slice provided
+        # Handle a slice
         if isinstance(key, slice):
-            try:
-                queryset._cursor_obj = queryset._cursor[key]
-                queryset._skip, queryset._limit = key.start, key.stop
-                if key.start and key.stop:
-                    queryset._limit = key.stop - key.start
-            except IndexError as err:
-                # PyMongo raises an error if key.start == key.stop, catch it,
-                # bin it, kill it.
-                start = key.start or 0
-                if start >= 0 and key.stop >= 0 and key.step is None:
-                    if start == key.stop:
-                        queryset.limit(0)
-                        queryset._skip = key.start
-                        queryset._limit = key.stop - start
-                        return queryset
-                raise err
+            queryset._cursor_obj = queryset._cursor[key]
+            queryset._skip, queryset._limit = key.start, key.stop
+            if key.start and key.stop:
+                queryset._limit = key.stop - key.start
+
             # Allow further QuerySet modifications to be performed
             return queryset
-        # Integer index provided
+
+        # Handle an index
         elif isinstance(key, int):
             if queryset._scalar:
                 return queryset._get_scalar(
-                    queryset._document._from_son(queryset._cursor[key],
-                                                 _auto_dereference=self._auto_dereference,
-                                                 only_fields=self.only_fields))
+                    queryset._document._from_son(
+                        queryset._cursor[key],
+                        _auto_dereference=self._auto_dereference,
+                        only_fields=self.only_fields
+                    )
+                )
 
             if queryset._as_pymongo:
                 return queryset._get_as_pymongo(queryset._cursor[key])
-            return queryset._document._from_son(queryset._cursor[key],
-                                                _auto_dereference=self._auto_dereference,
-                                                only_fields=self.only_fields)
 
-        raise AttributeError
+            return queryset._document._from_son(
+                queryset._cursor[key],
+                _auto_dereference=self._auto_dereference,
+                only_fields=self.only_fields
+            )
+
+        raise AttributeError('Provide a slice or an integer index')
 
     def __iter__(self):
         raise NotImplementedError
@@ -204,14 +208,12 @@ class BaseQuerySet(object):
         queryset = self.order_by()
         return False if queryset.first() is None else True
 
-    def __nonzero__(self):
-        """Avoid to open all records in an if stmt in Py2."""
-        return self._has_data()
-
     def __bool__(self):
         """Avoid to open all records in an if stmt in Py3."""
         return self._has_data()
 
+    __nonzero__ = __bool__  # For Py2 support
+
     # Core functions
 
     def all(self):
@@ -264,13 +266,13 @@ class BaseQuerySet(object):
         queryset = queryset.filter(*q_objs, **query)
 
         try:
-            result = queryset.next()
+            result = six.next(queryset)
         except StopIteration:
             msg = ('%s matching query does not exist.'
                    % queryset._document._class_name)
             raise queryset._document.DoesNotExist(msg)
         try:
-            queryset.next()
+            six.next(queryset)
         except StopIteration:
             return result
 
@@ -285,7 +287,7 @@ class BaseQuerySet(object):
 
         .. versionadded:: 0.4
         """
-        return self._document(**kwargs).save()
+        return self._document(**kwargs).save(force_insert=True)
 
     def first(self):
         """Retrieve the first object matching the query."""
@@ -345,11 +347,24 @@ class BaseQuerySet(object):
                                      documents=docs, **signal_kwargs)
 
         raw = [doc.to_mongo() for doc in docs]
+
+        with set_write_concern(self._collection, write_concern) as collection:
+            insert_func = collection.insert_many
+            if return_one:
+                raw = raw[0]
+                insert_func = collection.insert_one
+
         try:
-            ids = self._collection.insert(raw, **write_concern)
+            inserted_result = insert_func(raw)
+            ids = return_one and [inserted_result.inserted_id] or inserted_result.inserted_ids
         except pymongo.errors.DuplicateKeyError as err:
             message = 'Could not save document (%s)'
             raise NotUniqueError(message % six.text_type(err))
+        except pymongo.errors.BulkWriteError as err:
+            # inserting documents that already have an _id field will
+            # give huge performance debt or raise
+            message = u'Document must not have _id value before bulk write (%s)'
+            raise NotUniqueError(message % six.text_type(err))
         except pymongo.errors.OperationFailure as err:
             message = 'Could not save document (%s)'
             if re.match('^E1100[01] duplicate key', six.text_type(err)):
@@ -363,7 +378,6 @@ class BaseQuerySet(object):
             signals.post_bulk_insert.send(
                 self._document, documents=docs, loaded=False, **signal_kwargs)
             return return_one and ids[0] or ids
-
         documents = self.in_bulk(ids)
         results = []
         for obj_id in ids:
@@ -379,7 +393,7 @@ class BaseQuerySet(object):
             :meth:`skip` that has been applied to this cursor into account when
             getting the count
         """
-        if self._limit == 0 and with_limit_and_skip or self._none:
+        if self._limit == 0 and with_limit_and_skip is False or self._none:
             return 0
         return self._cursor.count(with_limit_and_skip=with_limit_and_skip)
 
@@ -481,8 +495,9 @@ class BaseQuerySet(object):
             ``save(..., write_concern={w: 2, fsync: True}, ...)`` will
             wait until at least two servers have recorded the write and
             will force an fsync on the primary server.
-        :param full_result: Return the full result rather than just the number
-            updated.
+        :param full_result: Return the full result dictionary rather than just the number
+            updated, e.g. return
+            ``{'n': 2, 'nModified': 2, 'ok': 1.0, 'updatedExisting': True}``.
         :param update: Django-style update keyword arguments
 
         .. versionadded:: 0.2
@@ -505,12 +520,15 @@ class BaseQuerySet(object):
             else:
                 update['$set'] = {'_cls': queryset._document._class_name}
         try:
-            result = queryset._collection.update(query, update, multi=multi,
-                                                 upsert=upsert, **write_concern)
+            with set_write_concern(queryset._collection, write_concern) as collection:
+                update_func = collection.update_one
+                if multi:
+                    update_func = collection.update_many
+                result = update_func(query, update, upsert=upsert)
             if full_result:
                 return result
-            elif result:
-                return result['n']
+            elif result.raw_result:
+                return result.raw_result['n']
         except pymongo.errors.DuplicateKeyError as err:
             raise NotUniqueError(u'Update failed (%s)' % six.text_type(err))
         except pymongo.errors.OperationFailure as err:
@@ -539,10 +557,10 @@ class BaseQuerySet(object):
                                     write_concern=write_concern,
                                     full_result=True, **update)
 
-        if atomic_update['updatedExisting']:
+        if atomic_update.raw_result['updatedExisting']:
             document = self.get()
         else:
-            document = self._document.objects.with_id(atomic_update['upserted'])
+            document = self._document.objects.with_id(atomic_update.upserted_id)
         return document
 
     def update_one(self, upsert=False, write_concern=None, **update):
@@ -706,39 +724,37 @@ class BaseQuerySet(object):
         with switch_db(self._document, alias) as cls:
             collection = cls._get_collection()
 
-        return self.clone_into(self.__class__(self._document, collection))
+        return self._clone_into(self.__class__(self._document, collection))
 
     def clone(self):
-        """Creates a copy of the current
-          :class:`~mongoengine.queryset.QuerySet`
+        """Create a copy of the current queryset."""
+        return self._clone_into(self.__class__(self._document, self._collection_obj))
 
-        .. versionadded:: 0.5
+    def _clone_into(self, new_qs):
+        """Copy all of the relevant properties of this queryset to
+        a new queryset (which has to be an instance of
+        :class:`~mongoengine.queryset.base.BaseQuerySet`).
         """
-        return self.clone_into(self.__class__(self._document, self._collection_obj))
-
-    def clone_into(self, cls):
-        """Creates a copy of the current
-          :class:`~mongoengine.queryset.base.BaseQuerySet` into another child class
-        """
-        if not isinstance(cls, BaseQuerySet):
+        if not isinstance(new_qs, BaseQuerySet):
             raise OperationError(
-                '%s is not a subclass of BaseQuerySet' % cls.__name__)
+                '%s is not a subclass of BaseQuerySet' % new_qs.__name__)
 
         copy_props = ('_mongo_query', '_initial_query', '_none', '_query_obj',
-                      '_where_clause', '_loaded_fields', '_ordering', '_snapshot',
-                      '_timeout', '_class_check', '_slave_okay', '_read_preference',
-                      '_iter', '_scalar', '_as_pymongo', '_as_pymongo_coerce',
+                      '_where_clause', '_loaded_fields', '_ordering',
+                      '_snapshot', '_timeout', '_class_check', '_slave_okay',
+                      '_read_preference', '_iter', '_scalar', '_as_pymongo',
                       '_limit', '_skip', '_hint', '_auto_dereference',
-                      '_search_text', 'only_fields', '_max_time_ms')
+                      '_search_text', 'only_fields', '_max_time_ms',
+                      '_comment')
 
         for prop in copy_props:
             val = getattr(self, prop)
-            setattr(cls, prop, copy.copy(val))
+            setattr(new_qs, prop, copy.copy(val))
 
         if self._cursor_obj:
-            cls._cursor_obj = self._cursor_obj.clone()
+            new_qs._cursor_obj = self._cursor_obj.clone()
 
-        return cls
+        return new_qs
 
     def select_related(self, max_depth=1):
         """Handles dereferencing of :class:`~bson.dbref.DBRef` objects or
@@ -756,11 +772,16 @@ class BaseQuerySet(object):
         """Limit the number of returned documents to `n`. This may also be
         achieved using array-slicing syntax (e.g. ``User.objects[:5]``).
 
-        :param n: the maximum number of objects to return
+        :param n: the maximum number of objects to return if n is greater than 0.
+        When 0 is passed, returns all the documents in the cursor
         """
         queryset = self.clone()
-        queryset._limit = n if n != 0 else 1
-        # Return self to allow chaining
+        queryset._limit = n
+
+        # If a cursor object has already been created, apply the limit to it.
+        if queryset._cursor_obj:
+            queryset._cursor_obj.limit(queryset._limit)
+
         return queryset
 
     def skip(self, n):
@@ -771,6 +792,11 @@ class BaseQuerySet(object):
         """
         queryset = self.clone()
         queryset._skip = n
+
+        # If a cursor object has already been created, apply the skip to it.
+        if queryset._cursor_obj:
+            queryset._cursor_obj.skip(queryset._skip)
+
         return queryset
 
     def hint(self, index=None):
@@ -788,6 +814,11 @@ class BaseQuerySet(object):
         """
         queryset = self.clone()
         queryset._hint = index
+
+        # If a cursor object has already been created, apply the hint to it.
+        if queryset._cursor_obj:
+            queryset._cursor_obj.hint(queryset._hint)
+
         return queryset
 
     def batch_size(self, size):
@@ -801,6 +832,11 @@ class BaseQuerySet(object):
         """
         queryset = self.clone()
         queryset._batch_size = size
+
+        # If a cursor object has already been created, apply the batch size to it.
+        if queryset._cursor_obj:
+            queryset._cursor_obj.batch_size(queryset._batch_size)
+
         return queryset
 
     def distinct(self, field):
@@ -900,18 +936,25 @@ class BaseQuerySet(object):
         return self.fields(**fields)
 
     def fields(self, _only_called=False, **kwargs):
-        """Manipulate how you load this document's fields.  Used by `.only()`
-        and `.exclude()` to manipulate which fields to retrieve.  Fields also
-        allows for a greater level of control for example:
+        """Manipulate how you load this document's fields. Used by `.only()`
+        and `.exclude()` to manipulate which fields to retrieve. If called
+        directly, use a set of kwargs similar to the MongoDB projection
+        document. For example:
 
-        Retrieving a Subrange of Array Elements:
+        Include only a subset of fields:
 
-        You can use the $slice operator to retrieve a subrange of elements in
-        an array. For example to get the first 5 comments::
+            posts = BlogPost.objects(...).fields(author=1, title=1)
 
-            post = BlogPost.objects(...).fields(slice__comments=5)
+        Exclude a specific field:
 
-        :param kwargs: A dictionary identifying what to include
+            posts = BlogPost.objects(...).fields(comments=0)
+
+        To retrieve a subrange of array elements:
+
+            posts = BlogPost.objects(...).fields(slice__comments=5)
+
+        :param kwargs: A set of keyword arguments identifying what to
+            include, exclude, or slice.
 
         .. versionadded:: 0.5
         """
@@ -927,7 +970,20 @@ class BaseQuerySet(object):
             key = '.'.join(parts)
             cleaned_fields.append((key, value))
 
-        fields = sorted(cleaned_fields, key=operator.itemgetter(1))
+        # Sort fields by their values, explicitly excluded fields first, then
+        # explicitly included, and then more complicated operators such as
+        # $slice.
+        def _sort_key(field_tuple):
+            key, value = field_tuple
+            if isinstance(value, (int)):
+                return value  # 0 for exclusion, 1 for inclusion
+            else:
+                return 2  # so that complex values appear last
+
+        fields = sorted(cleaned_fields, key=_sort_key)
+
+        # Clone the queryset, group all fields by their value, convert
+        # each of them to db_fields, and set the queryset's _loaded_fields
         queryset = self.clone()
         for value, group in itertools.groupby(fields, lambda x: x[1]):
             fields = [field for field, value in group]
@@ -953,13 +1009,31 @@ class BaseQuerySet(object):
     def order_by(self, *keys):
         """Order the :class:`~mongoengine.queryset.QuerySet` by the keys. The
         order may be specified by prepending each of the keys by a + or a -.
-        Ascending order is assumed.
+        Ascending order is assumed. If no keys are passed, existing ordering
+        is cleared instead.
 
         :param keys: fields to order the query results by; keys may be
             prefixed with **+** or **-** to determine the ordering direction
         """
         queryset = self.clone()
-        queryset._ordering = queryset._get_order_by(keys)
+
+        old_ordering = queryset._ordering
+        new_ordering = queryset._get_order_by(keys)
+
+        if queryset._cursor_obj:
+
+            # If a cursor object has already been created, apply the sort to it
+            if new_ordering:
+                queryset._cursor_obj.sort(new_ordering)
+
+            # If we're trying to clear a previous explicit ordering, we need
+            # to clear the cursor entirely (because PyMongo doesn't allow
+            # clearing an existing sort on a cursor).
+            elif old_ordering:
+                queryset._cursor_obj = None
+
+        queryset._ordering = new_ordering
+
         return queryset
 
     def comment(self, text):
@@ -1069,16 +1143,15 @@ class BaseQuerySet(object):
         """An alias for scalar"""
         return self.scalar(*fields)
 
-    def as_pymongo(self, coerce_types=False):
+    def as_pymongo(self):
         """Instead of returning Document instances, return raw values from
         pymongo.
 
-        :param coerce_types: Field types (if applicable) would be use to
-            coerce types.
+        This method is particularly useful if you don't need dereferencing
+        and care primarily about the speed of data retrieval.
         """
         queryset = self.clone()
         queryset._as_pymongo = True
-        queryset._as_pymongo_coerce = coerce_types
         return queryset
 
     def max_time_ms(self, ms):
@@ -1123,6 +1196,10 @@ class BaseQuerySet(object):
 
         pipeline = initial_pipeline + list(pipeline)
 
+        if IS_PYMONGO_3 and self._read_preference is not None:
+            return self._collection.with_options(read_preference=self._read_preference) \
+                       .aggregate(pipeline, cursor={}, **kwargs)
+
         return self._collection.aggregate(pipeline, cursor={}, **kwargs)
 
     # JS functionality
@@ -1398,27 +1475,31 @@ class BaseQuerySet(object):
 
     # Iterator helpers
 
-    def next(self):
+    def __next__(self):
         """Wrap the result in a :class:`~mongoengine.Document` object.
         """
         if self._limit == 0 or self._none:
             raise StopIteration
 
-        raw_doc = self._cursor.next()
+        raw_doc = six.next(self._cursor)
+
         if self._as_pymongo:
             return self._get_as_pymongo(raw_doc)
-        doc = self._document._from_son(raw_doc,
-                                       _auto_dereference=self._auto_dereference, only_fields=self.only_fields)
+
+        doc = self._document._from_son(
+            raw_doc, _auto_dereference=self._auto_dereference,
+            only_fields=self.only_fields)
 
         if self._scalar:
             return self._get_scalar(doc)
 
         return doc
 
+    next = __next__     # For Python2 support
+
     def rewind(self):
         """Rewind the cursor to its unevaluated state.
 
-
         .. versionadded:: 0.3
         """
         self._iter = False
@@ -1468,43 +1549,57 @@ class BaseQuerySet(object):
 
     @property
     def _cursor(self):
-        if self._cursor_obj is None:
+        """Return a PyMongo cursor object corresponding to this queryset."""
 
-            # In PyMongo 3+, we define the read preference on a collection
-            # level, not a cursor level. Thus, we need to get a cloned
-            # collection object using `with_options` first.
-            if IS_PYMONGO_3 and self._read_preference is not None:
-                self._cursor_obj = self._collection\
-                    .with_options(read_preference=self._read_preference)\
-                    .find(self._query, **self._cursor_args)
-            else:
-                self._cursor_obj = self._collection.find(self._query,
-                                                         **self._cursor_args)
-            # Apply where clauses to cursor
-            if self._where_clause:
-                where_clause = self._sub_js_fields(self._where_clause)
-                self._cursor_obj.where(where_clause)
+        # If _cursor_obj already exists, return it immediately.
+        if self._cursor_obj is not None:
+            return self._cursor_obj
 
-            if self._ordering:
-                # Apply query ordering
-                self._cursor_obj.sort(self._ordering)
-            elif self._ordering is None and self._document._meta['ordering']:
-                # Otherwise, apply the ordering from the document model, unless
-                # it's been explicitly cleared via order_by with no arguments
-                order = self._get_order_by(self._document._meta['ordering'])
-                self._cursor_obj.sort(order)
+        # Create a new PyMongo cursor.
+        # XXX In PyMongo 3+, we define the read preference on a collection
+        # level, not a cursor level. Thus, we need to get a cloned collection
+        # object using `with_options` first.
+        if IS_PYMONGO_3 and self._read_preference is not None:
+            self._cursor_obj = self._collection\
+                .with_options(read_preference=self._read_preference)\
+                .find(self._query, **self._cursor_args)
+        else:
+            self._cursor_obj = self._collection.find(self._query,
+                                                     **self._cursor_args)
+        # Apply "where" clauses to cursor
+        if self._where_clause:
+            where_clause = self._sub_js_fields(self._where_clause)
+            self._cursor_obj.where(where_clause)
 
-            if self._limit is not None:
-                self._cursor_obj.limit(self._limit)
+        # Apply ordering to the cursor.
+        # XXX self._ordering can be equal to:
+        # * None if we didn't explicitly call order_by on this queryset.
+        # * A list of PyMongo-style sorting tuples.
+        # * An empty list if we explicitly called order_by() without any
+        #   arguments. This indicates that we want to clear the default
+        #   ordering.
+        if self._ordering:
+            # explicit ordering
+            self._cursor_obj.sort(self._ordering)
+        elif self._ordering is None and self._document._meta['ordering']:
+            # default ordering
+            order = self._get_order_by(self._document._meta['ordering'])
+            self._cursor_obj.sort(order)
 
-            if self._skip is not None:
-                self._cursor_obj.skip(self._skip)
+        if self._limit is not None:
+            self._cursor_obj.limit(self._limit)
 
-            if self._hint != -1:
-                self._cursor_obj.hint(self._hint)
+        if self._skip is not None:
+            self._cursor_obj.skip(self._skip)
 
-            if self._batch_size is not None:
-                self._cursor_obj.batch_size(self._batch_size)
+        if self._hint != -1:
+            self._cursor_obj.hint(self._hint)
+
+        if self._batch_size is not None:
+            self._cursor_obj.batch_size(self._batch_size)
+
+        if self._comment is not None:
+            self._cursor_obj.comment(self._comment)
 
         return self._cursor_obj
 
@@ -1650,25 +1745,33 @@ class BaseQuerySet(object):
         return frequencies
 
     def _fields_to_dbfields(self, fields):
-        """Translate fields paths to its db equivalents"""
-        ret = []
+        """Translate fields' paths to their db equivalents."""
         subclasses = []
-        document = self._document
-        if document._meta['allow_inheritance']:
+        if self._document._meta['allow_inheritance']:
             subclasses = [get_document(x)
-                          for x in document._subclasses][1:]
+                          for x in self._document._subclasses][1:]
+
+        db_field_paths = []
         for field in fields:
+            field_parts = field.split('.')
             try:
-                field = '.'.join(f.db_field for f in
-                                 document._lookup_field(field.split('.')))
-                ret.append(field)
+                field = '.'.join(
+                    f if isinstance(f, six.string_types) else f.db_field
+                    for f in self._document._lookup_field(field_parts)
+                )
+                db_field_paths.append(field)
             except LookUpError as err:
                 found = False
+
+                # If a field path wasn't found on the main document, go
+                # through its subclasses and see if it exists on any of them.
                 for subdoc in subclasses:
                     try:
-                        subfield = '.'.join(f.db_field for f in
-                                            subdoc._lookup_field(field.split('.')))
-                        ret.append(subfield)
+                        subfield = '.'.join(
+                            f if isinstance(f, six.string_types) else f.db_field
+                            for f in subdoc._lookup_field(field_parts)
+                        )
+                        db_field_paths.append(subfield)
                         found = True
                         break
                     except LookUpError:
@@ -1676,10 +1779,17 @@ class BaseQuerySet(object):
 
                 if not found:
                     raise err
-        return ret
+
+        return db_field_paths
 
     def _get_order_by(self, keys):
-        """Creates a list of order by fields"""
+        """Given a list of MongoEngine-style sort keys, return a list
+        of sorting tuples that can be applied to a PyMongo cursor. For
+        example:
+
+        >>> qs._get_order_by(['-last_name', 'first_name'])
+        [('last_name', -1), ('first_name', 1)]
+        """
         key_list = []
         for key in keys:
             if not key:
@@ -1692,17 +1802,19 @@ class BaseQuerySet(object):
             direction = pymongo.ASCENDING
             if key[0] == '-':
                 direction = pymongo.DESCENDING
+
             if key[0] in ('-', '+'):
                 key = key[1:]
+
             key = key.replace('__', '.')
             try:
                 key = self._document._translate_field_name(key)
             except Exception:
+                # TODO this exception should be more specific
                 pass
+
             key_list.append((key, direction))
 
-        if self._cursor_obj and key_list:
-            self._cursor_obj.sort(key_list)
         return key_list
 
     def _get_scalar(self, doc):
@@ -1719,59 +1831,25 @@ class BaseQuerySet(object):
 
         return tuple(data)
 
-    def _get_as_pymongo(self, row):
-        # Extract which fields paths we should follow if .fields(...) was
-        # used. If not, handle all fields.
-        if not getattr(self, '__as_pymongo_fields', None):
-            self.__as_pymongo_fields = []
+    def _get_as_pymongo(self, doc):
+        """Clean up a PyMongo doc, removing fields that were only fetched
+        for the sake of MongoEngine's implementation, and return it.
+        """
+        # Always remove _cls as a MongoEngine's implementation detail.
+        if '_cls' in doc:
+            del doc['_cls']
 
-            for field in self._loaded_fields.fields - set(['_cls']):
-                self.__as_pymongo_fields.append(field)
-                while '.' in field:
-                    field, _ = field.rsplit('.', 1)
-                    self.__as_pymongo_fields.append(field)
+        # If the _id was not included in a .only or was excluded in a .exclude,
+        # remove it from the doc (we always fetch it so that we can properly
+        # construct documents).
+        fields = self._loaded_fields
+        if fields and '_id' in doc and (
+            (fields.value == QueryFieldList.ONLY and '_id' not in fields.fields) or
+            (fields.value == QueryFieldList.EXCLUDE and '_id' in fields.fields)
+        ):
+            del doc['_id']
 
-        all_fields = not self.__as_pymongo_fields
-
-        def clean(data, path=None):
-            path = path or ''
-
-            if isinstance(data, dict):
-                new_data = {}
-                for key, value in data.iteritems():
-                    new_path = '%s.%s' % (path, key) if path else key
-
-                    if all_fields:
-                        include_field = True
-                    elif self._loaded_fields.value == QueryFieldList.ONLY:
-                        include_field = new_path in self.__as_pymongo_fields
-                    else:
-                        include_field = new_path not in self.__as_pymongo_fields
-
-                    if include_field:
-                        new_data[key] = clean(value, path=new_path)
-                data = new_data
-            elif isinstance(data, list):
-                data = [clean(d, path=path) for d in data]
-            else:
-                if self._as_pymongo_coerce:
-                    # If we need to coerce types, we need to determine the
-                    # type of this field and use the corresponding
-                    # .to_python(...)
-                    EmbeddedDocumentField = _import_class('EmbeddedDocumentField')
-
-                    obj = self._document
-                    for chunk in path.split('.'):
-                        obj = getattr(obj, chunk, None)
-                        if obj is None:
-                            break
-                        elif isinstance(obj, EmbeddedDocumentField):
-                            obj = obj.document_type
-                    if obj and data is not None:
-                        data = obj.to_python(data)
-            return data
-
-        return clean(row)
+        return doc
 
     def _sub_js_fields(self, code):
         """When fields are specified with [~fieldname] syntax, where
@@ -1800,10 +1878,21 @@ class BaseQuerySet(object):
         return code
 
     def _chainable_method(self, method_name, val):
+        """Call a particular method on the PyMongo cursor call a particular chainable method
+        with the provided value.
+        """
         queryset = self.clone()
-        method = getattr(queryset._cursor, method_name)
-        method(val)
+
+        # Get an existing cursor object or create a new one
+        cursor = queryset._cursor
+
+        # Find the requested method on the cursor and call it with the
+        # provided value
+        getattr(cursor, method_name)(val)
+
+        # Cache the value on the queryset._{method_name}
         setattr(queryset, '_' + method_name, val)
+
         return queryset
 
     # Deprecated

mongoengine/queryset/field_list.py

@@ -63,9 +63,11 @@ class QueryFieldList(object):
             self._only_called = True
         return self
 
-    def __nonzero__(self):
+    def __bool__(self):
         return bool(self.fields)
 
+    __nonzero__ = __bool__  # For Py2 support
+
     def as_dict(self):
         field_list = {field: self.value for field in self.fields}
         if self.slice:

mongoengine/queryset/manager.py

@@ -36,7 +36,7 @@ class QuerySetManager(object):
         queryset_class = owner._meta.get('queryset_class', self.default)
         queryset = queryset_class(owner, owner._get_collection())
         if self.get_queryset:
-            arg_count = self.get_queryset.func_code.co_argcount
+            arg_count = self.get_queryset.__code__.co_argcount
             if arg_count == 1:
                 queryset = self.get_queryset(queryset)
             elif arg_count == 2:

mongoengine/queryset/queryset.py

@@ -1,3 +1,5 @@
+import six
+
 from mongoengine.errors import OperationError
 from mongoengine.queryset.base import (BaseQuerySet, CASCADE, DENY, DO_NOTHING,
                                        NULLIFY, PULL)
@@ -87,10 +89,10 @@ class QuerySet(BaseQuerySet):
                 yield self._result_cache[pos]
                 pos += 1
 
-            # Raise StopIteration if we already established there were no more
+            # return if we already established there were no more
             # docs in the db cursor.
             if not self._has_more:
-                raise StopIteration
+                return
 
             # Otherwise, populate more of the cache and repeat.
             if len(self._result_cache) <= pos:
@@ -112,8 +114,8 @@ class QuerySet(BaseQuerySet):
         # Pull in ITER_CHUNK_SIZE docs from the database and store them in
         # the result cache.
         try:
-            for _ in xrange(ITER_CHUNK_SIZE):
-                self._result_cache.append(self.next())
+            for _ in six.moves.range(ITER_CHUNK_SIZE):
+                self._result_cache.append(six.next(self))
         except StopIteration:
             # Getting this exception means there are no more docs in the
             # db cursor. Set _has_more to False so that we can use that
@@ -136,13 +138,15 @@ class QuerySet(BaseQuerySet):
         return self._len
 
     def no_cache(self):
-        """Convert to a non_caching queryset
+        """Convert to a non-caching queryset
 
         .. versionadded:: 0.8.3 Convert to non caching queryset
         """
         if self._result_cache is not None:
             raise OperationError('QuerySet already cached')
-        return self.clone_into(QuerySetNoCache(self._document, self._collection))
+
+        return self._clone_into(QuerySetNoCache(self._document,
+                                                self._collection))
 
 
 class QuerySetNoCache(BaseQuerySet):
@@ -153,7 +157,7 @@ class QuerySetNoCache(BaseQuerySet):
 
         .. versionadded:: 0.8.3 Convert to caching queryset
         """
-        return self.clone_into(QuerySet(self._document, self._collection))
+        return self._clone_into(QuerySet(self._document, self._collection))
 
     def __repr__(self):
         """Provides the string representation of the QuerySet
@@ -164,9 +168,9 @@ class QuerySetNoCache(BaseQuerySet):
             return '.. queryset mid-iteration ..'
 
         data = []
-        for _ in xrange(REPR_OUTPUT_SIZE + 1):
+        for _ in six.moves.range(REPR_OUTPUT_SIZE + 1):
             try:
-                data.append(self.next())
+                data.append(six.next(self))
             except StopIteration:
                 break
 

mongoengine/queryset/transform.py

@@ -101,8 +101,8 @@ def query(_doc_cls=None, **kwargs):
                         value = value['_id']
 
             elif op in ('in', 'nin', 'all', 'near') and not isinstance(value, dict):
-                # 'in', 'nin' and 'all' require a list of values
-                value = [field.prepare_query_value(op, v) for v in value]
+                # Raise an error if the in/nin/all/near param is not iterable.
+                value = _prepare_query_for_iterable(field, op, value)
 
             # If we're querying a GenericReferenceField, we need to alter the
             # key depending on the value:
@@ -147,7 +147,7 @@ def query(_doc_cls=None, **kwargs):
         if op is None or key not in mongo_query:
             mongo_query[key] = value
         elif key in mongo_query:
-            if isinstance(mongo_query[key], dict):
+            if isinstance(mongo_query[key], dict) and isinstance(value, dict):
                 mongo_query[key].update(value)
                 # $max/minDistance needs to come last - convert to SON
                 value_dict = mongo_query[key]
@@ -201,31 +201,37 @@ def update(_doc_cls=None, **update):
     format.
     """
     mongo_update = {}
+
     for key, value in update.items():
         if key == '__raw__':
             mongo_update.update(value)
             continue
+
         parts = key.split('__')
+
         # if there is no operator, default to 'set'
         if len(parts) < 3 and parts[0] not in UPDATE_OPERATORS:
             parts.insert(0, 'set')
+
         # Check for an operator and transform to mongo-style if there is
         op = None
         if parts[0] in UPDATE_OPERATORS:
             op = parts.pop(0)
             # Convert Pythonic names to Mongo equivalents
-            if op in ('push_all', 'pull_all'):
-                op = op.replace('_all', 'All')
-            elif op == 'dec':
+            operator_map = {
+                'push_all': 'pushAll',
+                'pull_all': 'pullAll',
+                'dec': 'inc',
+                'add_to_set': 'addToSet',
+                'set_on_insert': 'setOnInsert'
+            }
+            if op == 'dec':
                 # Support decrement by flipping a positive value's sign
                 # and using 'inc'
-                op = 'inc'
-                if value > 0:
-                    value = -value
-            elif op == 'add_to_set':
-                op = 'addToSet'
-            elif op == 'set_on_insert':
-                op = 'setOnInsert'
+                value = -value
+            # If the operator doesn't found from operator map, the op value
+            # will stay unchanged
+            op = operator_map.get(op, op)
 
         match = None
         if parts[-1] in COMPARISON_OPERATORS:
@@ -272,7 +278,15 @@ def update(_doc_cls=None, **update):
             if isinstance(field, GeoJsonBaseField):
                 value = field.to_mongo(value)
 
-            if op in (None, 'set', 'push', 'pull'):
+            if op == 'pull':
+                if field.required or value is not None:
+                    if match == 'in' and not isinstance(value, dict):
+                        value = _prepare_query_for_iterable(field, op, value)
+                    else:
+                        value = field.prepare_query_value(op, value)
+            elif op == 'push' and isinstance(value, (list, tuple, set)):
+                value = [field.prepare_query_value(op, v) for v in value]
+            elif op in (None, 'set', 'push'):
                 if field.required or value is not None:
                     value = field.prepare_query_value(op, value)
             elif op in ('pushAll', 'pullAll'):
@@ -284,6 +298,8 @@ def update(_doc_cls=None, **update):
                     value = field.prepare_query_value(op, value)
             elif op == 'unset':
                 value = 1
+            elif op == 'inc':
+                value = field.prepare_query_value(op, value)
 
         if match:
             match = '$' + match
@@ -307,11 +323,17 @@ def update(_doc_cls=None, **update):
             field_classes = [c.__class__ for c in cleaned_fields]
             field_classes.reverse()
             ListField = _import_class('ListField')
-            if ListField in field_classes:
-                # Join all fields via dot notation to the last ListField
+            EmbeddedDocumentListField = _import_class('EmbeddedDocumentListField')
+            if ListField in field_classes or EmbeddedDocumentListField in field_classes:
+                # Join all fields via dot notation to the last ListField or EmbeddedDocumentListField
                 # Then process as normal
+                if ListField in field_classes:
+                    _check_field = ListField
+                else:
+                    _check_field = EmbeddedDocumentListField
+
                 last_listField = len(
-                    cleaned_fields) - field_classes.index(ListField)
+                    cleaned_fields) - field_classes.index(_check_field)
                 key = '.'.join(parts[:last_listField])
                 parts = parts[last_listField:]
                 parts.insert(0, key)
@@ -321,10 +343,26 @@ def update(_doc_cls=None, **update):
                 value = {key: value}
         elif op == 'addToSet' and isinstance(value, list):
             value = {key: {'$each': value}}
+        elif op in ('push', 'pushAll'):
+            if parts[-1].isdigit():
+                key = parts[0]
+                position = int(parts[-1])
+                # $position expects an iterable. If pushing a single value,
+                # wrap it in a list.
+                if not isinstance(value, (set, tuple, list)):
+                    value = [value]
+                value = {key: {'$each': value, '$position': position}}
+            else:
+                if op == 'pushAll':
+                    op = 'push'  # convert to non-deprecated keyword
+                    if not isinstance(value, (set, tuple, list)):
+                        value = [value]
+                    value = {key: {'$each': value}}
+                else:
+                    value = {key: value}
         else:
             value = {key: value}
         key = '$' + op
-
         if key not in mongo_update:
             mongo_update[key] = value
         elif key in mongo_update and isinstance(mongo_update[key], dict):
@@ -413,3 +451,22 @@ def _infer_geometry(value):
 
     raise InvalidQueryError('Invalid $geometry data. Can be either a '
                             'dictionary or (nested) lists of coordinate(s)')
+
+
+def _prepare_query_for_iterable(field, op, value):
+    # We need a special check for BaseDocument, because - although it's iterable - using
+    # it as such in the context of this method is most definitely a mistake.
+    BaseDocument = _import_class('BaseDocument')
+
+    if isinstance(value, BaseDocument):
+        raise TypeError("When using the `in`, `nin`, `all`, or "
+                        "`near`-operators you can\'t use a "
+                        "`Document`, you must wrap your object "
+                        "in a list (object -> [object]).")
+
+    if not hasattr(value, '__iter__'):
+        raise TypeError("The `in`, `nin`, `all`, or "
+                        "`near`-operators must be applied to an "
+                        "iterable (e.g. a list).")
+
+    return [field.prepare_query_value(op, v) for v in value]