diff --git a/moto/dynamodb2/models.py b/moto/dynamodb2/models.py index 6bcde41b2..f04bb830f 100644 --- a/moto/dynamodb2/models.py +++ b/moto/dynamodb2/models.py @@ -724,7 +724,7 @@ class Table(BaseModel): if idx_col_set.issubset(set(hash_set.attrs)): yield hash_set - def scan(self, filters, limit, exclusive_start_key, filter_expression=None, index_name=None): + def scan(self, filters, limit, exclusive_start_key, filter_expression=None, index_name=None, projection_expression=None): results = [] scanned_count = 0 all_indexes = self.all_indexes() @@ -763,6 +763,14 @@ class Table(BaseModel): if passes_all_conditions: results.append(item) + if projection_expression: + expressions = [x.strip() for x in projection_expression.split(',')] + results = copy.deepcopy(results) + for result in results: + for attr in list(result.attrs): + if attr not in expressions: + result.attrs.pop(attr) + results, last_evaluated_key = self._trim_results(results, limit, exclusive_start_key, index_name) return results, scanned_count, last_evaluated_key @@ -962,7 +970,7 @@ class DynamoDBBackend(BaseBackend): return table.query(hash_key, range_comparison, range_values, limit, exclusive_start_key, scan_index_forward, projection_expression, index_name, filter_expression, **filter_kwargs) - def scan(self, table_name, filters, limit, exclusive_start_key, filter_expression, expr_names, expr_values, index_name): + def scan(self, table_name, filters, limit, exclusive_start_key, filter_expression, expr_names, expr_values, index_name, projection_expression): table = self.tables.get(table_name) if not table: return None, None, None @@ -977,7 +985,7 @@ class DynamoDBBackend(BaseBackend): else: filter_expression = Op(None, None) # Will always eval to true - return table.scan(scan_filters, limit, exclusive_start_key, filter_expression, index_name) + return table.scan(scan_filters, limit, exclusive_start_key, filter_expression, index_name, projection_expression) def update_item(self, table_name, key, update_expression, attribute_updates, expression_attribute_names, expression_attribute_values, expected=None): diff --git a/moto/dynamodb2/responses.py b/moto/dynamodb2/responses.py index 7eb565747..01f2df088 100644 --- a/moto/dynamodb2/responses.py +++ b/moto/dynamodb2/responses.py @@ -558,7 +558,7 @@ class DynamoHandler(BaseResponse): filter_expression = self.body.get('FilterExpression') expression_attribute_values = self.body.get('ExpressionAttributeValues', {}) expression_attribute_names = self.body.get('ExpressionAttributeNames', {}) - + projection_expression = self.body.get('ProjectionExpression') exclusive_start_key = self.body.get('ExclusiveStartKey') limit = self.body.get("Limit") index_name = self.body.get('IndexName') @@ -570,7 +570,8 @@ class DynamoHandler(BaseResponse): filter_expression, expression_attribute_names, expression_attribute_values, - index_name) + index_name, + projection_expression) except InvalidIndexNameError as err: er = 'com.amazonaws.dynamodb.v20111205#ValidationException' return self.error(er, str(err)) diff --git a/tests/test_dynamodb2/test_dynamodb.py b/tests/test_dynamodb2/test_dynamodb.py index 77846de04..67610ad72 100644 --- a/tests/test_dynamodb2/test_dynamodb.py +++ b/tests/test_dynamodb2/test_dynamodb.py @@ -452,6 +452,90 @@ def test_basic_projection_expressions(): assert 'body' in results['Items'][1] assert 'forum_name' in results['Items'][1] +@mock_dynamodb2 +def test_basic_projection_expressions_using_scan(): + dynamodb = boto3.resource('dynamodb', region_name='us-east-1') + + # Create the DynamoDB table. + table = dynamodb.create_table( + TableName='users', + KeySchema=[ + { + 'AttributeName': 'forum_name', + 'KeyType': 'HASH' + }, + { + 'AttributeName': 'subject', + 'KeyType': 'RANGE' + }, + ], + AttributeDefinitions=[ + { + 'AttributeName': 'forum_name', + 'AttributeType': 'S' + }, + { + 'AttributeName': 'subject', + 'AttributeType': 'S' + }, + ], + ProvisionedThroughput={ + 'ReadCapacityUnits': 5, + 'WriteCapacityUnits': 5 + } + ) + table = dynamodb.Table('users') + + table.put_item(Item={ + 'forum_name': 'the-key', + 'subject': '123', + 'body': 'some test message' + }) + + table.put_item(Item={ + 'forum_name': 'not-the-key', + 'subject': '123', + 'body': 'some other test message' + }) + # Test a query returning all items + results = table.scan( + FilterExpression=Key('forum_name').eq( + 'the-key'), + ProjectionExpression='body, subject' + ) + + assert 'body' in results['Items'][0] + assert results['Items'][0]['body'] == 'some test message' + assert 'subject' in results['Items'][0] + + table.put_item(Item={ + 'forum_name': 'the-key', + 'subject': '1234', + 'body': 'yet another test message' + }) + + results = table.scan( + FilterExpression=Key('forum_name').eq( + 'the-key'), + ProjectionExpression='body' + ) + + assert 'body' in results['Items'][0] + assert 'subject' not in results['Items'][0] + assert results['Items'][0]['body'] == 'some test message' + assert 'body' in results['Items'][1] + assert 'subject' not in results['Items'][1] + assert results['Items'][1]['body'] == 'yet another test message' + + # The projection expression should not remove data from storage + results = table.query( + KeyConditionExpression=Key('forum_name').eq( + 'the-key'), + ) + assert 'subject' in results['Items'][0] + assert 'body' in results['Items'][1] + assert 'forum_name' in results['Items'][1] + @mock_dynamodb2 def test_basic_projection_expressions_with_attr_expression_names():