cleaner Document._save_update

CONTRIBUTING.rst

@@ -14,7 +14,7 @@ Before starting to write code, look for existing `tickets
 <https://github.com/MongoEngine/mongoengine/issues?state=open>`_ or `create one
 <https://github.com/MongoEngine/mongoengine/issues>`_ for your specific
 issue or feature request. That way you avoid working on something
-that might not be of interest or that has already been addressed.  If in doubt
+that might not be of interest or that has already been addressed. If in doubt
 post to the `user group <http://groups.google.com/group/mongoengine-users>`
 
 Supported Interpreters

README.rst

@@ -57,7 +57,7 @@ Some simple examples of what MongoEngine code looks like:
 
     class BlogPost(Document):
         title = StringField(required=True, max_length=200)
-        posted = DateTimeField(default=datetime.datetime.now)
+        posted = DateTimeField(default=datetime.datetime.utcnow)
         tags = ListField(StringField(max_length=50))
         meta = {'allow_inheritance': True}
 
@@ -87,17 +87,18 @@ Some simple examples of what MongoEngine code looks like:
     ...     print
     ...
 
-    >>> len(BlogPost.objects)
+    # Count all blog posts and its subtypes
+    >>> BlogPost.objects.count()
     2
-    >>> len(TextPost.objects)
+    >>> TextPost.objects.count()
     1
-    >>> len(LinkPost.objects)
+    >>> LinkPost.objects.count()
     1
 
-    # Find tagged posts
-    >>> len(BlogPost.objects(tags='mongoengine'))
+    # Count tagged posts
+    >>> BlogPost.objects(tags='mongoengine').count()
     2
-    >>> len(BlogPost.objects(tags='mongodb'))
+    >>> BlogPost.objects(tags='mongodb').count()
     1
 
 Tests
@@ -130,8 +131,7 @@ Community
   <http://groups.google.com/group/mongoengine-users>`_
 - `MongoEngine Developers mailing list
   <http://groups.google.com/group/mongoengine-dev>`_
-- `#mongoengine IRC channel <http://webchat.freenode.net/?channels=mongoengine>`_
 
 Contributing
 ============
-We welcome contributions! see  the `Contribution guidelines <https://github.com/MongoEngine/mongoengine/blob/master/CONTRIBUTING.rst>`_
+We welcome contributions! See the `Contribution guidelines <https://github.com/MongoEngine/mongoengine/blob/master/CONTRIBUTING.rst>`_

docs/guide/connecting.rst

@@ -33,7 +33,7 @@ the :attr:`host` to
     corresponding parameters in :func:`~mongoengine.connect`: ::
 
         connect(
-            name='test',
+            db='test',
             username='user',
             password='12345',
             host='mongodb://admin:qwerty@localhost/production'

mongoengine/base/common.py

@@ -5,7 +5,7 @@ __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'])
+                        'set_on_insert', 'min', 'max', 'rename'])
 
 
 _document_registry = {}

mongoengine/base/document.py

@@ -402,9 +402,11 @@ 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)

mongoengine/document.py

@@ -313,6 +313,9 @@ 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 +332,20 @@ 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 +358,7 @@ 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 +371,91 @@ 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 _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
+
+        updates, removals = self._delta()
+        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')
+            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.
@@ -828,7 +859,6 @@ 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 []
 

mongoengine/queryset/base.py

@@ -933,7 +933,20 @@ 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]

mongoengine/queryset/transform.py

@@ -233,8 +233,7 @@ def update(_doc_cls=None, **update):
                 # Support decrement by flipping a positive value's sign
                 # and using 'inc'
                 op = 'inc'
-                if value > 0:
-                    value = -value
+                value = -value
             elif op == 'add_to_set':
                 op = 'addToSet'
             elif op == 'set_on_insert':

tests/document/instance.py

@@ -435,6 +435,15 @@ class InstanceTest(unittest.TestCase):
 
         person.to_dbref()
 
+    def test_save_abstract_document(self):
+        """Saving an abstract document should fail."""
+        class Doc(Document):
+            name = StringField()
+            meta = {'abstract': True}
+
+        with self.assertRaises(InvalidDocumentError):
+            Doc(name='aaa').save()
+
     def test_reload(self):
         """Ensure that attributes may be reloaded.
         """
@@ -1223,6 +1232,19 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(person.name, None)
         self.assertEqual(person.age, None)
 
+    def test_update_rename_operator(self):
+        """Test the $rename operator."""
+        coll = self.Person._get_collection()
+        doc = self.Person(name='John').save()
+        raw_doc = coll.find_one({'_id': doc.pk})
+        self.assertEqual(set(raw_doc.keys()), set(['_id', '_cls', 'name']))
+
+        doc.update(rename__name='first_name')
+        raw_doc = coll.find_one({'_id': doc.pk})
+        self.assertEqual(set(raw_doc.keys()),
+                         set(['_id', '_cls', 'first_name']))
+        self.assertEqual(raw_doc['first_name'], 'John')
+
     def test_inserts_if_you_set_the_pk(self):
         p1 = self.Person(name='p1', id=bson.ObjectId()).save()
         p2 = self.Person(name='p2')

tests/queryset/field_list.py

@@ -141,6 +141,16 @@ class OnlyExcludeAllTest(unittest.TestCase):
         self.assertEqual(qs._loaded_fields.as_dict(),
                          {'b': {'$slice': 5}})
 
+    def test_mix_slice_with_other_fields(self):
+        class MyDoc(Document):
+            a = ListField()
+            b = ListField()
+            c = ListField()
+
+        qs = MyDoc.objects.fields(a=1, b=0, slice__c=2)
+        self.assertEqual(qs._loaded_fields.as_dict(),
+                         {'c': {'$slice': 2}, 'a': 1})
+
     def test_only(self):
         """Ensure that QuerySet.only only returns the requested fields.
         """

tests/queryset/queryset.py

@@ -1826,6 +1826,11 @@ class QuerySetTest(unittest.TestCase):
         post.reload()
         self.assertEqual(post.hits, 10)
 
+        # Negative dec operator is equal to a positive inc operator
+        BlogPost.objects.update_one(dec__hits=-1)
+        post.reload()
+        self.assertEqual(post.hits, 11)
+
         BlogPost.objects.update(push__tags='mongo')
         post.reload()
         self.assertTrue('mongo' in post.tags)

tests/test_connection.py

@@ -296,6 +296,19 @@ class ConnectionTest(unittest.TestCase):
         conn = get_connection('t2')
         self.assertFalse(get_tz_awareness(conn))
 
+    def test_write_concern(self):
+        """Ensure write concern can be specified in connect() via
+        a kwarg or as part of the connection URI.
+        """
+        conn1 = connect(alias='conn1', host='mongodb://localhost/testing?w=1&j=true')
+        conn2 = connect('testing', alias='conn2', w=1, j=True)
+        if IS_PYMONGO_3:
+            self.assertEqual(conn1.write_concern.document, {'w': 1, 'j': True})
+            self.assertEqual(conn2.write_concern.document, {'w': 1, 'j': True})
+        else:
+            self.assertEqual(dict(conn1.write_concern), {'w': 1, 'j': True})
+            self.assertEqual(dict(conn2.write_concern), {'w': 1, 'j': True})
+
     def test_datetime(self):
         connect('mongoenginetest', tz_aware=True)
         d = datetime.datetime(2010, 5, 5, tzinfo=utc)