def process_function(self, node):
assert isinstance(node, UpdateExpressionFunction)
function_name = node.get_function_name()
first_arg = node.get_nth_argument(1)
second_arg = node.get_nth_argument(2)
if function_name == "if_not_exists":
if isinstance(first_arg, NoneExistingPath):
result = second_arg
else:
result = first_arg
assert isinstance(result, (DDBTypedValue, NoneExistingPath))
return result
elif function_name == "list_append":
first_arg = deepcopy(
self.get_list_from_ddb_typed_value(first_arg, function_name))
second_arg = self.get_list_from_ddb_typed_value(
second_arg, function_name)
for list_element in second_arg.value:
first_arg.value.append(list_element)
return DDBTypedValue(first_arg)
else:
raise NotImplementedError(
"Unsupported function for moto {name}".format(
name=function_name))
def replace_expression_attribute_value_with_value(self, node):
"""A node representing an Expression Attribute Value. Resolve and replace value"""
assert isinstance(node, ExpressionAttributeValue)
attribute_value_name = node.get_value_name()
try:
target = self.expression_attribute_values[attribute_value_name]
except KeyError:
raise ExpressionAttributeValueNotDefined(
attribute_value=attribute_value_name)
return DDBTypedValue(DynamoType(target))
def get_subtraction(cls, left_operand, right_operand):
"""
Args:
left_operand(DynamoType):
right_operand(DynamoType):
Returns:
DDBTypedValue:
"""
try:
return DDBTypedValue(left_operand - right_operand)
except TypeError:
raise IncorrectOperandType("-", left_operand.type)
def resolve_expression_path_nodes(self, item,
update_expression_path_nodes):
target = item.attrs
for child in update_expression_path_nodes:
# First replace placeholder with attribute_name
attr_name = None
if isinstance(child, ExpressionAttributeName):
attr_placeholder = child.get_attribute_name_placeholder()
try:
attr_name = self.expression_attribute_names[
attr_placeholder]
except KeyError:
raise ExpressionAttributeNameNotDefined(attr_placeholder)
elif isinstance(child, ExpressionAttribute):
attr_name = child.get_attribute_name()
self.raise_exception_if_keyword(attr_name)
if attr_name is not None:
# Resolv attribute_name
try:
target = target[attr_name]
except (KeyError, TypeError):
if child == update_expression_path_nodes[-1]:
return NoneExistingPath(creatable=True)
return NoneExistingPath()
else:
if isinstance(child, ExpressionPathDescender):
continue
elif isinstance(child, ExpressionSelector):
index = child.get_index()
if target.is_list():
try:
target = target[index]
except IndexError:
# When a list goes out of bounds when assigning that is no problem when at the assignment
# side. It will just append to the list.
if child == update_expression_path_nodes[-1]:
return NoneExistingPath(creatable=True)
return NoneExistingPath()
else:
raise InvalidUpdateExpressionInvalidDocumentPath
else:
raise NotImplementedError(
"Path resolution for {t}".format(t=type(child)))
if not isinstance(target, DynamoType):
print(target)
return DDBTypedValue(target)