allows udpate multiple attributes at once

docs/tutorial.rst

@@ -281,3 +281,12 @@ atomically updating the view count of an item:
 
     >>> thread_item.update_item('views', 1, action='add')
 
+Multiple attributes can be updated at once too:
+
+.. code-block:: python
+
+    >>> thread_item.update_item({
+            'views': {'value': 1, 'action': 'add'},
+            'last_view': {'value' time(), 'action': 'put'},
+        })
+

pynamodb/models.py

@@ -316,7 +316,15 @@ def update_item(self, attribute, value=None, action=None, conditional_operator=N
         """
         Updates an item using the UpdateItem operation.
 
-        This should be used for updating a single attribute of an item.
+        This should be used for updating attributes of an item.
+
+        In case multiple attributes are updates, the parameters `value` and `action` should be omited
+        and all the attributes should be passed as the first parameter in the following format
+
+        {
+            attr_name: {'value': 10, 'action': 'ADD'},
+            next_attr: {'value': True, 'action': 'PUT'},
+        }
 
         :param attribute: The name of the attribute to be updated
         :param value: The new value for the attribute.
@@ -325,27 +333,33 @@ def update_item(self, attribute, value=None, action=None, conditional_operator=N
         """
         self._conditional_operator_check(conditional_operator)
         args, save_kwargs = self._get_save_args(null_check=False)
-        attribute_cls = None
-        for attr_name, attr_cls in self._get_attributes().items():
-            if attr_name == attribute:
-                value = attr_cls.serialize(value)
-                attribute_cls = attr_cls
-                break
-        if save_kwargs.get(pythonic(RANGE_KEY)):
-            kwargs = {pythonic(RANGE_KEY): save_kwargs.get(pythonic(RANGE_KEY))}
-        else:
-            kwargs = {}
-        if len(expected_values):
-            kwargs.update(expected=self._build_expected_values(expected_values, UPDATE_FILTER_OPERATOR_MAP))
-        kwargs[pythonic(ATTR_UPDATES)] = {
-            attribute_cls.attr_name: {
-                ACTION: action.upper() if action else None,
-            }
+        kwargs = {
+            pythonic(RETURN_VALUES):  ALL_NEW,
+            pythonic(ATTR_UPDATES): {},
+            'conditional_operator': conditional_operator,
         }
-        if action is not None and action.upper() != DELETE:
-            kwargs[pythonic(ATTR_UPDATES)][attribute_cls.attr_name][VALUE] = {ATTR_TYPE_MAP[attribute_cls.attr_type]: value}
-        kwargs[pythonic(RETURN_VALUES)] = ALL_NEW
-        kwargs.update(conditional_operator=conditional_operator)
+
+        if pythonic(RANGE_KEY) in save_kwargs:
+            kwargs[pythonic(RANGE_KEY)] = save_kwargs[pythonic(RANGE_KEY)]
+
+        if len(expected_values):
+            kwargs['expected'] = self._build_expected_values(expected_values, UPDATE_FILTER_OPERATOR_MAP)
+
+        # if it's a single attribute, convert it to a dict of attrs
+        if type(attribute) is not dict:
+            attribute = {attribute: {'value': value, 'action': action}}
+        elif value or action:
+            raise ValueError("parameters `value` and `action` can be used only for a single attribute update")
+
+        for attr, params in attribute.items():
+            attribute_cls = self._get_attributes()[attr]
+            action, value = params['action'] and params['action'].upper(), attribute_cls.serialize(params['value'])
+            attr_value = {ACTION: action}
+            if action != DELETE:
+                attr_value[VALUE] = {ATTR_TYPE_MAP[attribute_cls.attr_type]: value}
+
+            kwargs[pythonic(ATTR_UPDATES)][attribute_cls.attr_name] = attr_value
+
         data = self._get_connection().update_item(
             *args,
             **kwargs

pynamodb/tests/test_model.py

@@ -1125,6 +1125,41 @@ def test_update_item(self):
             }
             deep_eq(args, params, _assert=True)
 
+        with patch(PATCH_METHOD) as req:
+            item.update_item({
+                'is_active': {'value': False, 'action': 'put'},
+                'views': {'value': 10, 'action': 'add'}
+            })
+
+            args = req.call_args[0][1]
+            params = {
+                'TableName': 'SimpleModel',
+                'ReturnValues': 'ALL_NEW',
+                'Key': {
+                    'user_name': {
+                        'S': 'foo'
+                    }
+                },
+                'AttributeUpdates': {
+                    'is_active': {
+                        'Action': 'PUT',
+                        'Value': {
+                            'BOOL': False,
+                        }
+                    },
+                    'views': {
+                        'Action': 'ADD',
+                        'Value': {
+                            'N': '10',
+                        }
+                    }
+
+                },
+                'ReturnConsumedCapacity': 'TOTAL'
+            }
+
+            deep_eq(args, params, _assert=True)
+
 
     def test_save(self):
         """