Extending Models

[johannesschobel]

Dear @a-chacon ,

thanks again for this project - great work.
I was stumbling upon an issue, where i want to extend the models you already provide. In particular, the Url model. I want to add an additional qrcode attribute via ActiveStorage with

has_one_attached :qrcode

How can i achieve the latter in the best / rails way?
I see 2 options:

1. extend your class with class UrlWithQRCode < RailsUrlShortener::Url and add functionality there
2. we could add a generator (i.e., rails g urlshortener:install) that basically copies (!) all your models / controllers / ... to respective directories within app (i.e., like devise would do it). This way, the developer can easily customize / adjust everything.

What do you think?
All the best,
Johannes

[a-chacon]

Hi! mm I like the second option, but this will convert the engine to a generator only. Let me think about it!

Did you try something with class_eval? Like:

´´´ruby
RailsUrlShortener::Url.class_eval do
has_one_attached :qrcode
end
´´´

That into an initializer? I dont know if that can works but It will prevent to develop new things and could be a quick solution.

[johannesschobel]

no, that does not need to be a generator only approach.

Consider, for example, devise.
Devise offers to copy respective files into the app folder, in order to be customized (i.e., new ui or adjust the controller logic). However, this can be omitted, if not needed (i.e., if I am happy with the default controller logic, i do not need to extend / adjust the controller).

Maybe this approach could be an idea for RailsUrlShortener as well

[johannesschobel]

I did not try the class_eval approach you mention.
However, i guess, i would like to add some before / after commit actions as well, like creating the QRCode, writing the latter to disk and attaching the ActiveStorage record to the model, ...

I think, this would be quite cumbersome and hard-to-remember, if there is crucial business logic within an initializer (and not within the model itself)