fix flake8

.travis.yml

@@ -1,7 +1,7 @@
 language: python
 
 python:
-- '2.6'
+- '2.6'  # TODO remove in v0.11.0
 - '2.7'
 - '3.3'
 - '3.4'

mongoengine/base/datastructures.py

@@ -438,7 +438,7 @@ class StrictDict(object):
                 __slots__ = allowed_keys_tuple
 
                 def __repr__(self):
-                    return "{%s}" % ', '.join('"{0!s}": {0!r}'.format(k) for k in self.iterkeys())
+                    return "{%s}" % ', '.join('"{0!s}": {1!r}'.format(k, v) for k, v in self.items())
 
             cls._classes[allowed_keys] = SpecificStrictDict
         return cls._classes[allowed_keys]

mongoengine/connection.py

@@ -25,7 +25,8 @@ _dbs = {}
 
 def register_connection(alias, name=None, host=None, port=None,
                         read_preference=READ_PREFERENCE,
-                        username=None, password=None, authentication_source=None,
+                        username=None, password=None,
+                        authentication_source=None,
                         authentication_mechanism=None,
                         **kwargs):
     """Add a connection.
@@ -70,20 +71,26 @@ def register_connection(alias, name=None, host=None, port=None,
 
     resolved_hosts = []
     for entity in conn_host:
-        # Handle uri style connections
+
+        # Handle Mongomock
         if entity.startswith('mongomock://'):
             conn_settings['is_mock'] = True
             # `mongomock://` is not a valid url prefix and must be replaced by `mongodb://`
             resolved_hosts.append(entity.replace('mongomock://', 'mongodb://', 1))
+
+        # Handle URI style connections, only updating connection params which
+        # were explicitly specified in the URI.
         elif '://' in entity:
             uri_dict = uri_parser.parse_uri(entity)
             resolved_hosts.append(entity)
-            conn_settings.update({
-                'name': uri_dict.get('database') or name,
-                'username': uri_dict.get('username'),
-                'password': uri_dict.get('password'),
-                'read_preference': read_preference,
-            })
+
+            if uri_dict.get('database'):
+                conn_settings['name'] = uri_dict.get('database')
+
+            for param in ('read_preference', 'username', 'password'):
+                if uri_dict.get(param):
+                    conn_settings[param] = uri_dict[param]
+
             uri_options = uri_dict['options']
             if 'replicaset' in uri_options:
                 conn_settings['replicaSet'] = True

mongoengine/fields.py

@@ -577,7 +577,7 @@ class EmbeddedDocumentField(BaseField):
         return self.document_type._fields.get(member_name)
 
     def prepare_query_value(self, op, value):
-        if not isinstance(value, self.document_type):
+        if value is not None and not isinstance(value, self.document_type):
             value = self.document_type._from_son(value)
         super(EmbeddedDocumentField, self).prepare_query_value(op, value)
         return self.to_mongo(value)
@@ -1249,7 +1249,7 @@ class GenericReferenceField(BaseField):
         if document is None:
             return None
 
-        if isinstance(document, (dict, SON)):
+        if isinstance(document, (dict, SON, ObjectId, DBRef)):
             return document
 
         id_field_name = document.__class__._meta['id_field']

mongoengine/python_support.py

@@ -1,9 +1,22 @@
-"""Helper functions and types to aid with Python 2.5 - 3 support."""
+"""Helper functions and types to aid with Python 2.6 - 3 support."""
 
 import sys
+import warnings
+
 import pymongo
 
 
+# Show a deprecation warning for people using Python v2.6
+# TODO remove in mongoengine v0.11.0
+if sys.version_info[0] == 2 and sys.version_info[1] == 6:
+    warnings.warn(
+        'Python v2.6 support is deprecated and is going to be dropped '
+        'entirely in the upcoming v0.11.0 release. Update your Python '
+        'version if you want to have access to the latest features and '
+        'bug fixes in MongoEngine.',
+        DeprecationWarning
+    )
+
 if pymongo.version_tuple[0] < 3:
     IS_PYMONGO_3 = False
 else:

mongoengine/queryset/base.py

@@ -82,6 +82,7 @@ class BaseQuerySet(object):
         self._limit = None
         self._skip = None
         self._hint = -1  # Using -1 as None is a valid value for hint
+        self._batch_size = None
         self.only_fields = []
         self._max_time_ms = None
 
@@ -275,6 +276,8 @@ class BaseQuerySet(object):
         except StopIteration:
             return result
 
+        # If we were able to retrieve the 2nd doc, rewind the cursor and
+        # raise the MultipleObjectsReturned exception.
         queryset.rewind()
         message = u'%d items returned, instead of 1' % queryset.count()
         raise queryset._document.MultipleObjectsReturned(message)
@@ -444,7 +447,7 @@ class BaseQuerySet(object):
                 if doc._collection == document_cls._collection:
                     for ref in queryset:
                         cascade_refs.add(ref.id)
-                ref_q = document_cls.objects(**{field_name + '__in': self, 'id__nin': cascade_refs})
+                ref_q = document_cls.objects(**{field_name + '__in': self, 'pk__nin': cascade_refs})
                 ref_q_count = ref_q.count()
                 if ref_q_count > 0:
                     ref_q.delete(write_concern=write_concern, cascade_refs=cascade_refs)
@@ -781,6 +784,19 @@ class BaseQuerySet(object):
         queryset._hint = index
         return queryset
 
+    def batch_size(self, size):
+        """Limit the number of documents returned in a single batch (each
+        batch requires a round trip to the server).
+
+        See http://api.mongodb.com/python/current/api/pymongo/cursor.html#pymongo.cursor.Cursor.batch_size
+        for details.
+
+        :param size: desired size of each batch.
+        """
+        queryset = self.clone()
+        queryset._batch_size = size
+        return queryset
+
     def distinct(self, field):
         """Return a list of distinct values for a given field.
 
@@ -933,6 +949,14 @@ class BaseQuerySet(object):
         queryset._ordering = queryset._get_order_by(keys)
         return queryset
 
+    def comment(self, text):
+        """Add a comment to the query.
+
+        See https://docs.mongodb.com/manual/reference/method/cursor.comment/#cursor.comment
+        for details.
+        """
+        return self._chainable_method("comment", text)
+
     def explain(self, format=False):
         """Return an explain plan record for the
         :class:`~mongoengine.queryset.QuerySet`\ 's cursor.
@@ -1459,6 +1483,9 @@ class BaseQuerySet(object):
             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)
+
         return self._cursor_obj
 
     def __deepcopy__(self, memo):

mongoengine/queryset/queryset.py

@@ -27,9 +27,10 @@ class QuerySet(BaseQuerySet):
         in batches of ``ITER_CHUNK_SIZE``.
 
         If ``self._has_more`` the cursor hasn't been exhausted so cache then
-        batch.  Otherwise iterate the result_cache.
+        batch. Otherwise iterate the result_cache.
         """
         self._iter = True
+
         if self._has_more:
             return self._iter_results()
 
@@ -42,10 +43,12 @@ class QuerySet(BaseQuerySet):
         """
         if self._len is not None:
             return self._len
+
+        # Populate the result cache with *all* of the docs in the cursor
         if self._has_more:
-            # populate the cache
             list(self._iter_results())
 
+        # Cache the length of the complete result cache and return it
         self._len = len(self._result_cache)
         return self._len
 
@@ -64,18 +67,33 @@ class QuerySet(BaseQuerySet):
     def _iter_results(self):
         """A generator for iterating over the result cache.
 
-        Also populates the cache if there are more possible results to yield.
-        Raises StopIteration when there are no more results"""
+        Also populates the cache if there are more possible results to
+        yield. Raises StopIteration when there are no more results.
+        """
         if self._result_cache is None:
             self._result_cache = []
+
         pos = 0
         while True:
-            upper = len(self._result_cache)
-            while pos < upper:
+
+            # For all positions lower than the length of the current result
+            # cache, serve the docs straight from the cache w/o hitting the
+            # database.
+            # XXX it's VERY important to compute the len within the `while`
+            # condition because the result cache might expand mid-iteration
+            # (e.g. if we call len(qs) inside a loop that iterates over the
+            # queryset). Fortunately len(list) is O(1) in Python, so this
+            # doesn't cause performance issues.
+            while pos < len(self._result_cache):
                 yield self._result_cache[pos]
                 pos += 1
+
+            # Raise StopIteration if we already established there were no more
+            # docs in the db cursor.
             if not self._has_more:
                 raise StopIteration
+
+            # Otherwise, populate more of the cache and repeat.
             if len(self._result_cache) <= pos:
                 self._populate_cache()
 
@@ -86,12 +104,22 @@ class QuerySet(BaseQuerySet):
         """
         if self._result_cache is None:
             self._result_cache = []
-        if self._has_more:
-            try:
-                for i in xrange(ITER_CHUNK_SIZE):
-                    self._result_cache.append(self.next())
-            except StopIteration:
-                self._has_more = False
+
+        # Skip populating the cache if we already established there are no
+        # more docs to pull from the database.
+        if not self._has_more:
+            return
+
+        # Pull in ITER_CHUNK_SIZE docs from the database and store them in
+        # the result cache.
+        try:
+            for i in xrange(ITER_CHUNK_SIZE):
+                self._result_cache.append(self.next())
+        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
+            # information in other places.
+            self._has_more = False
 
     def count(self, with_limit_and_skip=False):
         """Count the selected elements in the query.

mongoengine/queryset/transform.py

@@ -1,6 +1,7 @@
 from collections import defaultdict
 
-from bson import SON
+from bson import ObjectId, SON
+from bson.dbref import DBRef
 import pymongo
 
 from mongoengine.base.fields import UPDATE_OPERATORS
@@ -26,6 +27,7 @@ MATCH_OPERATORS = (COMPARISON_OPERATORS + GEO_OPERATORS +
                    STRING_OPERATORS + CUSTOM_OPERATORS)
 
 
+# TODO make this less complex
 def query(_doc_cls=None, **kwargs):
     """Transform a query from Django-style format to Mongo format.
     """
@@ -62,6 +64,7 @@ def query(_doc_cls=None, **kwargs):
             parts = []
 
             CachedReferenceField = _import_class('CachedReferenceField')
+            GenericReferenceField = _import_class('GenericReferenceField')
 
             cleaned_fields = []
             for field in fields:
@@ -101,6 +104,16 @@ def query(_doc_cls=None, **kwargs):
                 # 'in', 'nin' and 'all' require a list of values
                 value = [field.prepare_query_value(op, v) for v in value]
 
+            # If we're querying a GenericReferenceField, we need to alter the
+            # key depending on the value:
+            # * If the value is a DBRef, the key should be "field_name._ref".
+            # * If the value is an ObjectId, the key should be "field_name._ref.$id".
+            if isinstance(field, GenericReferenceField):
+                if isinstance(value, DBRef):
+                    parts[-1] += '._ref'
+                elif isinstance(value, ObjectId):
+                    parts[-1] += '._ref.$id'
+
         # if op and op not in COMPARISON_OPERATORS:
         if op:
             if op in GEO_OPERATORS:
@@ -128,11 +141,13 @@ def query(_doc_cls=None, **kwargs):
 
         for i, part in indices:
             parts.insert(i, part)
+
         key = '.'.join(parts)
+
         if op is None or key not in mongo_query:
             mongo_query[key] = value
         elif key in mongo_query:
-            if key in mongo_query and isinstance(mongo_query[key], dict):
+            if isinstance(mongo_query[key], dict):
                 mongo_query[key].update(value)
                 # $max/minDistance needs to come last - convert to SON
                 value_dict = mongo_query[key]

setup.cfg

@@ -9,5 +9,5 @@ tests = tests
 [flake8]
 ignore=E501,F401,F403,F405,I201
 exclude=build,dist,docs,venv,.tox,.eggs,tests
-max-complexity=42
+max-complexity=45
 application-import-names=mongoengine,tests

tests/document/indexes.py

@@ -2,10 +2,8 @@
 import unittest
 import sys
 
-sys.path[0:0] = [""]
 
 import pymongo
-from random import randint
 
 from nose.plugins.skip import SkipTest
 from datetime import datetime
@@ -17,11 +15,9 @@ __all__ = ("IndexesTest", )
 
 
 class IndexesTest(unittest.TestCase):
-    _MAX_RAND = 10 ** 10
 
     def setUp(self):
-        self.db_name = 'mongoenginetest_IndexesTest_' + str(randint(0, self._MAX_RAND))
-        self.connection = connect(db=self.db_name)
+        self.connection = connect(db='mongoenginetest')
         self.db = get_db()
 
         class Person(Document):

tests/fields/fields.py

@@ -2810,6 +2810,38 @@ class FieldTest(unittest.TestCase):
         Post.drop_collection()
         User.drop_collection()
 
+    def test_generic_reference_filter_by_dbref(self):
+        """Ensure we can search for a specific generic reference by
+        providing its ObjectId.
+        """
+        class Doc(Document):
+            ref = GenericReferenceField()
+
+        Doc.drop_collection()
+
+        doc1 = Doc.objects.create()
+        doc2 = Doc.objects.create(ref=doc1)
+
+        doc = Doc.objects.get(ref=DBRef('doc', doc1.pk))
+        self.assertEqual(doc, doc2)
+
+    def test_generic_reference_filter_by_objectid(self):
+        """Ensure we can search for a specific generic reference by
+        providing its DBRef.
+        """
+        class Doc(Document):
+            ref = GenericReferenceField()
+
+        Doc.drop_collection()
+
+        doc1 = Doc.objects.create()
+        doc2 = Doc.objects.create(ref=doc1)
+
+        self.assertTrue(isinstance(doc1.pk, ObjectId))
+
+        doc = Doc.objects.get(ref=doc1.pk)
+        self.assertEqual(doc, doc2)
+
     def test_binary_fields(self):
         """Ensure that binary fields can be stored and retrieved.
         """

tests/queryset/queryset.py

@@ -337,9 +337,36 @@ class QuerySetTest(unittest.TestCase):
         query = query.filter(boolfield=True)
         self.assertEqual(query.count(), 1)
 
+    def test_batch_size(self):
+        """Ensure that batch_size works."""
+        class A(Document):
+            s = StringField()
+
+        A.drop_collection()
+
+        for i in range(100):
+            A.objects.create(s=str(i))
+
+        # test iterating over the result set
+        cnt = 0
+        for a in A.objects.batch_size(10):
+            cnt += 1
+        self.assertEqual(cnt, 100)
+
+        # test chaining
+        qs = A.objects.all()
+        qs = qs.limit(10).batch_size(20).skip(91)
+        cnt = 0
+        for a in qs:
+            cnt += 1
+        self.assertEqual(cnt, 9)
+
+        # test invalid batch size
+        qs = A.objects.batch_size(-1)
+        self.assertRaises(ValueError, lambda: list(qs))
+
     def test_update_write_concern(self):
         """Test that passing write_concern works"""
-
         self.Person.drop_collection()
 
         write_concern = {"fsync": True}
@@ -1239,7 +1266,8 @@ class QuerySetTest(unittest.TestCase):
             self.assertFalse('$orderby' in q.get_ops()[0]['query'])
 
     def test_find_embedded(self):
-        """Ensure that an embedded document is properly returned from a query.
+        """Ensure that an embedded document is properly returned from
+        a query.
         """
         class User(EmbeddedDocument):
             name = StringField()
@@ -1250,16 +1278,31 @@ class QuerySetTest(unittest.TestCase):
 
         BlogPost.drop_collection()
 
-        post = BlogPost(content='Had a good coffee today...')
-        post.author = User(name='Test User')
-        post.save()
+        BlogPost.objects.create(
+            author=User(name='Test User'),
+            content='Had a good coffee today...'
+        )
 
         result = BlogPost.objects.first()
         self.assertTrue(isinstance(result.author, User))
         self.assertEqual(result.author.name, 'Test User')
 
+    def test_find_empty_embedded(self):
+        """Ensure that you can save and find an empty embedded document."""
+        class User(EmbeddedDocument):
+            name = StringField()
+
+        class BlogPost(Document):
+            content = StringField()
+            author = EmbeddedDocumentField(User)
+
         BlogPost.drop_collection()
 
+        BlogPost.objects.create(content='Anonymous post...')
+
+        result = BlogPost.objects.get(author=None)
+        self.assertEqual(result.author, None)
+
     def test_find_dict_item(self):
         """Ensure that DictField items may be found.
         """
@@ -2199,6 +2242,21 @@ class QuerySetTest(unittest.TestCase):
             a.author.name for a in Author.objects.order_by('-author__age')]
         self.assertEqual(names, ['User A', 'User B', 'User C'])
 
+    def test_comment(self):
+        """Make sure adding a comment to the query works."""
+        class User(Document):
+            age = IntField()
+
+        with db_ops_tracker() as q:
+            adult = (User.objects.filter(age__gte=18)
+                .comment('looking for an adult')
+                .first())
+            ops = q.get_ops()
+            self.assertEqual(len(ops), 1)
+            op = ops[0]
+            self.assertEqual(op['query']['$query'], {'age': {'$gte': 18}})
+            self.assertEqual(op['query']['$comment'], 'looking for an adult')
+
     def test_map_reduce(self):
         """Ensure map/reduce is both mapping and reducing.
         """
@@ -4860,6 +4918,56 @@ class QuerySetTest(unittest.TestCase):
 
         self.assertEqual(1, Doc.objects(item__type__="axe").count())
 
+    def test_len_during_iteration(self):
+        """Tests that calling len on a queyset during iteration doesn't
+        stop paging.
+        """
+        class Data(Document):
+            pass
+
+        for i in xrange(300):
+            Data().save()
+
+        records = Data.objects.limit(250)
+
+        # This should pull all 250 docs from mongo and populate the result
+        # cache
+        len(records)
+
+        # Assert that iterating over documents in the qs touches every
+        # document even if we call len(qs) midway through the iteration.
+        for i, r in enumerate(records):
+            if i == 58:
+                len(records)
+        self.assertEqual(i, 249)
+
+        # Assert the same behavior is true even if we didn't pre-populate the
+        # result cache.
+        records = Data.objects.limit(250)
+        for i, r in enumerate(records):
+            if i == 58:
+                len(records)
+        self.assertEqual(i, 249)
+
+    def test_iteration_within_iteration(self):
+        """You should be able to reliably iterate over all the documents
+        in a given queryset even if there are multiple iterations of it
+        happening at the same time.
+        """
+        class Data(Document):
+            pass
+
+        for i in xrange(300):
+            Data().save()
+
+        qs = Data.objects.limit(250)
+        for i, doc in enumerate(qs):
+            for j, doc2 in enumerate(qs):
+                pass
+
+        self.assertEqual(i, 249)
+        self.assertEqual(j, 249)
+
 
 if __name__ == '__main__':
     unittest.main()

tests/test_connection.py

@@ -174,19 +174,9 @@ class ConnectionTest(unittest.TestCase):
         c.mongoenginetest.system.users.remove({})
 
     def test_connect_uri_without_db(self):
-        """Ensure connect() method works properly with uri's without database_name
+        """Ensure connect() method works properly if the URI doesn't
+        include a database name.
         """
-        c = connect(db='mongoenginetest', alias='admin')
-        c.admin.system.users.remove({})
-        c.mongoenginetest.system.users.remove({})
-
-        c.admin.add_user("admin", "password")
-        c.admin.authenticate("admin", "password")
-        c.mongoenginetest.add_user("username", "password")
-
-        if not IS_PYMONGO_3:
-            self.assertRaises(ConnectionError, connect, "testdb_uri_bad", host='mongodb://test:password@localhost')
-
         connect("mongoenginetest", host='mongodb://localhost/')
 
         conn = get_connection()
@@ -196,8 +186,31 @@ class ConnectionTest(unittest.TestCase):
         self.assertTrue(isinstance(db, pymongo.database.Database))
         self.assertEqual(db.name, 'mongoenginetest')
 
-        c.admin.system.users.remove({})
-        c.mongoenginetest.system.users.remove({})
+    def test_connect_uri_default_db(self):
+        """Ensure connect() defaults to the right database name if
+        the URI and the database_name don't explicitly specify it.
+        """
+        connect(host='mongodb://localhost/')
+
+        conn = get_connection()
+        self.assertTrue(isinstance(conn, pymongo.mongo_client.MongoClient))
+
+        db = get_db()
+        self.assertTrue(isinstance(db, pymongo.database.Database))
+        self.assertEqual(db.name, 'test')
+
+    def test_uri_without_credentials_doesnt_override_conn_settings(self):
+        """Ensure connect() uses the username & password params if the URI
+        doesn't explicitly specify them.
+        """
+        c = connect(host='mongodb://localhost/mongoenginetest',
+                    username='user',
+                    password='pass')
+
+        # OperationFailure means that mongoengine attempted authentication
+        # w/ the provided username/password and failed - that's the desired
+        # behavior. If the MongoDB URI would override the credentials
+        self.assertRaises(OperationFailure, get_db)
 
     def test_connect_uri_with_authsource(self):
         """Ensure that the connect() method works well with

tests/test_datastructures.py

@@ -1,5 +1,6 @@
 import unittest
-from mongoengine.base.datastructures import StrictDict, SemiStrictDict 
+
+from mongoengine.base.datastructures import StrictDict, SemiStrictDict
 
 
 class TestStrictDict(unittest.TestCase):
@@ -13,9 +14,17 @@ class TestStrictDict(unittest.TestCase):
         d = self.dtype(a=1, b=1, c=1)
         self.assertEqual((d.a, d.b, d.c), (1, 1, 1))
 
+    def test_repr(self):
+        d = self.dtype(a=1, b=2, c=3)
+        self.assertEqual(repr(d), '{"a": 1, "b": 2, "c": 3}')
+
+        # make sure quotes are escaped properly
+        d = self.dtype(a='"', b="'", c="")
+        self.assertEqual(repr(d), '{"a": \'"\', "b": "\'", "c": \'\'}')
+
     def test_init_fails_on_nonexisting_attrs(self):
         self.assertRaises(AttributeError, lambda: self.dtype(a=1, b=2, d=3))
-        
+
     def test_eq(self):
         d = self.dtype(a=1, b=1, c=1)
         dd = self.dtype(a=1, b=1, c=1)
@@ -24,7 +33,7 @@ class TestStrictDict(unittest.TestCase):
         g = self.strict_dict_class(("a", "b", "c", "d"))(a=1, b=1, c=1, d=1)
         h = self.strict_dict_class(("a", "c", "b"))(a=1, b=1, c=1)
         i = self.strict_dict_class(("a", "c", "b"))(a=1, b=1, c=2)
-        
+
         self.assertEqual(d, dd)
         self.assertNotEqual(d, e)
         self.assertNotEqual(d, f)
@@ -38,19 +47,19 @@ class TestStrictDict(unittest.TestCase):
         d.a = 1
         self.assertEqual(d.a, 1)
         self.assertRaises(AttributeError, lambda: d.b)
-    
+
     def test_setattr_raises_on_nonexisting_attr(self):
         d = self.dtype()
 
         def _f():
             d.x = 1
         self.assertRaises(AttributeError, _f)
-    
+
     def test_setattr_getattr_special(self):
         d = self.strict_dict_class(["items"])
         d.items = 1
         self.assertEqual(d.items, 1)
-    
+
     def test_get(self):
         d = self.dtype(a=1)
         self.assertEqual(d.get('a'), 1)
@@ -88,7 +97,7 @@ class TestSemiSrictDict(TestStrictDict):
     def test_init_succeeds_with_nonexisting_attrs(self):
         d = self.dtype(a=1, b=1, c=1, x=2)
         self.assertEqual((d.a, d.b, d.c, d.x), (1, 1, 1, 2))
-   
+
     def test_iter_with_nonexisting_attrs(self):
         d = self.dtype(a=1, b=1, c=1, x=2)
         self.assertEqual(list(d), ['a', 'b', 'c', 'x'])