How to create not persisted instance of active record class in rails?

Question

I am new to ruby and ruby on rails and I am trying to build a blog. This blog has articles, which are extending ActiveRecord::Base.

They have also some relations to tags or comments.

Now, I want to have the possibility to load articles from other sources than the DB. For example from my website, which is not the same app and provides a REST API to load articles.

How could I do this?

With an ActiveArticle which extends ActiveRecord::Base and an ExternalArticle which does not extends and an ArticleModule to implement the same features?

That seems to be not the right way. Thanks

Answer 1

A good chunk of what makes up a Rails model lives not in ActiveRecord, but in ActiveModel.

class ExternalArticle
  include ActiveModel::Model
end

will give you functionality like validations, callbacks, compatibility with URL helpers and so on.

See Railscast #219 for a short overview.

However, ActiveModel does not give you associations to other models. If you need those, the activerecord-tableless gem might help.

Edit:

I see now that your non-persisted model objects come from a REST API. Take a look at ActiveResource as well; it used to be part of Rails, but has been extracted into a separate gem as of Rails 4. It is basically ActiveRecord for remote objects.