使用PHP和JSON平面文件的最佳实践/方法

I'm creating a web app using PHP (Symfony2 framework) and I want to store some data that's created by the user, but I don't want to use a database. I think the best way to do this is JSON objects. Please look at my descriptions below and provide feedback on if this is a good way or bad way, or if it's even possible. I'm creating a web app using PHP (Symfony2 fram