Added SortedListField

mongodj/db/fields.py

@@ -42,4 +42,26 @@ def get_default(self):
                 return self.default()
             return self.default
         return []
-
+
+class SortedListField(ListField):
+    """A ListField that sorts the contents of its list before writing to
+    the database in order to ensure that a sorted list is always
+    retrieved.
+    """
+
+    _ordering = None
+
+    def __init__(self, *args, **kwargs):
+        if 'ordering' in kwargs.keys():
+            self._ordering = kwargs.pop('ordering')
+        super(SortedListField, self).__init__(*args, **kwargs)
+
+    def get_prep_value(self, value):
+        if value is None:
+            return None
+        if not isinstance(value, list):
+            if hasattr(value, "__iter__"):
+                value = list(value)
+        if self._ordering is not None:
+            return sorted(value, key=itemgetter(self._ordering))
+        return sorted(value)

testproj/myapp/models.py

@@ -1,6 +1,6 @@
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
-from mongodj.db.fields import ListField
+from mongodj.db.fields import ListField, SortedListField
 
 class StringAutoField(models.AutoField):
 
@@ -82,6 +82,8 @@ class TestFieldModel(models.Model):
     title = models.CharField(max_length=200)
     mlist = ListField()
     mlist_default = ListField(default=["a", "b"])
-
+    slist = SortedListField()
+    slist_default = SortedListField(default=["b", "a"])
+
     def __unicode__(self):
         return "Test special field model: %s" % (self.title)

testproj/myapp/tests.py

@@ -164,12 +164,17 @@ def test_complex_queries(self):
 
     def test_fields(self):
         t1 = TestFieldModel(title="p1", 
-                            mlist=["ab", "bc"])
+                            mlist=["ab", "bc"],
+                            slist=["bc", "ab"],
+                            )
         t1.save()
 
         t = TestFieldModel.objects.get(id=t1.id)
         self.assertEqual(t.mlist, ["ab", "bc"])
         self.assertEqual(t.mlist_default, ["a", "b"])
+        self.assertEqual(t.slist, ["ab", "bc"])
+        self.assertEqual(t.slist_default, ["a", "b"])
+
 
 #    def test_dates_year_month_day(self):
 #        now = datetime.datetime.now()