Added handling for callable collections

mongoengine/base.py

@@ -297,6 +297,11 @@ def __new__(cls, name, bases, attrs):
         # DocumentMetaclass before instantiating CollectionManager object
         new_class = super_new(cls, name, bases, attrs)
 
+        # Allow dynamically-generated collection names. Pass the newly
+        # created class so the callee has access to __module__, etc.
+        if callable(meta['collection']):
+            new_class._meta['collection'] = meta['collection'](new_class)
+
         # Provide a default queryset unless one has been manually provided
         if not hasattr(new_class, 'objects'):
             new_class.objects = QuerySetManager()

tests/document.py

@@ -61,6 +61,23 @@ class Person(Document):
         # Ensure Document isn't treated like an actual document
         self.assertFalse(hasattr(Document, '_fields'))
 
+    def test_dynamic_collection_naming(self):
+
+        def create_collection_name(cls):
+            return "PERSON"
+
+        class DynamicPerson(Document):
+            name = StringField()
+            age = IntField()
+
+            meta = {'collection': create_collection_name}
+
+        collection = DynamicPerson._get_collection_name()
+        self.assertEquals(collection, 'PERSON')
+
+        DynamicPerson(name='Test User', age=30).save()
+        self.assertTrue(collection in self.db.collection_names())
+
     def test_get_superclasses(self):
         """Ensure that the correct list of superclasses is assembled.
         """