Optimization to the sort implementation

The sort enum value is now a subclass of str that cat store the sort operator and be treated as string when creating the ast graph

Author: CaselIT

examples/flask_sqlalchemy/schema.py

@@ -34,8 +34,8 @@ class Meta:
 
 class Query(graphene.ObjectType):
     node = relay.Node.Field()
-    all_employees = SQLAlchemyConnectionField(
-        Employee, sort=graphene.Argument(SortEnumEmployee, default_value=['id', 'asc']))
+    all_employees = SQLAlchemyConnectionField(Employee, sort=graphene.Argument(SortEnumEmployee,
+            default_value=utils.EnumValue('id_asc', EmployeeModel.id.asc())))
     all_roles = SQLAlchemyConnectionField(Role, sort=utils.sort_argument_for_model(RoleModel))
     all_departments = SQLAlchemyConnectionField(Department)
 

graphene_sqlalchemy/fields.py

@@ -19,13 +19,10 @@ def model(self):
     def get_query(cls, model, info, sort=None, **args):
         query = get_query(model, info.context)
         if sort is not None:
-            if isinstance(sort[0], str):
-                sort = [sort]
-            order = []
-            for column_name, direction in sort:
-                column = getattr(model, column_name)
-                order.append(getattr(column, direction)())
-            query = query.order_by(*order)
+            if isinstance(sort, str):
+                query = query.order_by(sort.order)
+            else:
+                query = query.order_by(*(value.order for value in sort))
         return query
 
     @property

graphene_sqlalchemy/utils.py

@@ -42,16 +42,28 @@ def _symbol_name(column_name, is_asc):
     return column_name + ('_asc' if is_asc else '_desc')
 
 
+class EnumValue(str):
+    '''Subclass of str that stores a string value and the sort order of the column'''
+    def __new__(cls, str_value, order):
+        return super(EnumValue, cls).__new__(cls, str_value)
+
+    def __init__(self, str_value, order):
+        super(EnumValue, self).__init__()
+        self.order = order
+
+
 def _sort_enum_for_model(cls, name=None, symbol_name=_symbol_name):
     name = name or cls.__name__ + 'SortEnum'
     items = []
     default = []
     for column in inspect(cls).columns.values():
-        asc = symbol_name(column.name, True), [column.name, 'asc']
-        desc = symbol_name(column.name, False), [column.name, 'desc']
+        asc_name = symbol_name(column.name, True)
+        asc_value = EnumValue(asc_name, column.asc())
+        desc_name = symbol_name(column.name, False)
+        desc_value = EnumValue(desc_name, column.desc())
         if column.primary_key:
-            default.append(asc[1])
-        items.extend((asc, desc))
+            default.append(asc_value)
+        items.extend(((asc_name, asc_value), (desc_name, desc_value)))
     return Enum(name, items), default