Simple Form is a great gem I’ve been using extensively for most of my Rails projects. It’s one of those that go to Gemfile at the very beginning. However, I only used that for “real” models - derived from ActiveRecord and persisted in the database. Until yesterday. This might seem obvious, but here is a short guide on how to use Simple Form with other objects.
Use case was simple: a message and personal details that user enters on “Contact Us” page. There is, obviously, no point in storing that in database, however I though it would be nice to have a working prototype with Simple Form. Model goes as such:
As you see, it’s nothing fancy. I wanted it to be
OpenStruct to have a well-defined API. Including
include ActiveModel::Model is necessary for Simple Form to have methods such as
model_name, which one could define yourself, but ActiveModel is a dependency of Simple Form, so you will have it available anyway.
And that’s it. Simple and neat, and I have everything right away in my views:
This goes further. You can (and you should) treat this object like any other in controller. Here we go:
There is only one trick here. Classes formed from
Struct cannot be initialized like ActiveRecord (or OpenStruct) ones - with a hash. Therefore you need to define this little
from_hash method to properly initialize your object. In my case it is as simple as: