ruby递归查找某对象的父/子节点集合

def parent_ids
ids = []
parent_id = self.parent_id
while parent_role = Role.find_by_id(parent_id)
if parent_role
ids << parent_role.id
parent_id = parent_role.parent_id
else
break
end
end
ids
end

def children_ids
ids = []
parent_id = self.id
while child_role = Role.find_by_parent_id(parent_id)
if child_role
ids << child_role.id
parent_id = child_role.id
else
break
end
end
ids
end