Let's simplify using presenters in Rails.
gem "frosting" to your Gemfile and run
You have a
Post model. You're a good lil' rabbit, and it only contains methods concerned with its persistence.
So where do you put presentation-specific logic?
The view, right? Nah, man. You should probably use a presenter.
Let's say we're in
PostsController#show and you want to implement some sort of presentation logic. How about we're color coding based on the age of the post.
present @post from your controller (and its class is
Post), frosting will look for
Presenters::Post (defined in
/models/presenters/post.rb presumably). Here's what that could look like:
module Presenters class Post < Frosting::BasePresenter def color old? ? 'red' : 'green' end end end
#old? in your model because it's not a presentation concern. Good job.
Frosting::BasePresenter delegates to the resource you're presenting, and it also has access to the view context. It doesn't delegate anything by default, but you can delegate things like
content_tag if it makes your life easier. You should probably make your own base presenter that inherits from frosting's base. It's your life, and you should do what you want to.
You can also call
present_collection @posts should you be dealing with a collection of posts and want them all to be presented.
As an additional trick, if you find yourself writing code like:
def user present super(), context: @context end
in order to have your presented
Post return a presenter for the associated
User, then you can save some typing with:
presents_super method accepts options, so you can specify a presenter:
presents_super :user, presenter: SomeCustomPresenter
You can also use
presents_super for collections, by passing the
presents_super :users, collection: true
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