added GeoLocationField with auto index-creation for GEO2D

mongoengine/fields.py

@@ -12,7 +12,7 @@ __all__ = ['StringField', 'IntField', 'FloatField', 'BooleanField',
            'DateTimeField', 'EmbeddedDocumentField', 'ListField', 'DictField',
            'ObjectIdField', 'ReferenceField', 'ValidationError',
            'DecimalField', 'URLField', 'GenericReferenceField',
-           'BinaryField', 'EmailField']
+           'BinaryField', 'EmailField', 'GeoLocationField']
 
 RECURSIVE_REFERENCE_CONSTANT = 'self'
 
@@ -342,6 +342,23 @@ class DictField(BaseField):
     def lookup_member(self, member_name):
         return BaseField(db_field=member_name)
 
+class GeoLocationField(DictField):
+    """Supports geobased fields"""
+    
+    def validate(self, value):
+        """Make sure that a geo-value is of type (x, y)
+        """
+        if not isinstance(value, tuple) and not isinstance(value, list):
+            raise ValidationError('GeoLocationField can only hold tuples or lists of (x, y)')
+        
+        if len(value) <> 2:
+            raise ValidationError('GeoLocationField must have exactly two elements (x, y)')
+    
+    def to_mongo(self, value):
+        return {'x': value[0], 'y': value[1]}
+    
+    def to_python(self, value):
+        return value.keys()
 
 class ReferenceField(BaseField):
     """A reference to a document that will be automatically dereferenced on

mongoengine/queryset.py

@@ -4,7 +4,6 @@ import pymongo
 import re
 import copy
 
-
 __all__ = ['queryset_manager', 'Q', 'InvalidQueryError',
            'InvalidCollectionError']
 
@@ -242,6 +241,11 @@ class QuerySet(object):
             # If _types is being used (for polymorphism), it needs an index
             if '_types' in self._query:
                 self._collection.ensure_index('_types')
+            
+            # Ensure all needed field indexes are created
+            for field_name, field_instance in self._document._fields.iteritems():
+                if field_instance.__class__.__name__ == 'GeoLocationField':
+                    self._collection.ensure_index([(field_name, pymongo.GEO2D),])
         return self._collection_obj
 
     @property
@@ -297,7 +301,7 @@ class QuerySet(object):
         """Transform a query from Django-style format to Mongo format.
         """
         operators = ['ne', 'gt', 'gte', 'lt', 'lte', 'in', 'nin', 'mod',
-                     'all', 'size', 'exists']
+                     'all', 'size', 'exists', 'near']
         match_operators = ['contains', 'icontains', 'startswith', 
                            'istartswith', 'endswith', 'iendswith']