Display model's class and id when to_s not defined

[c-lliope]

https://trello.com/c/9OfUvC3x

Why?

Administrate relied on #to_s to display objects throughout the system,
but in order for it to work correctly developers needed to define #to_s
on each model that they wanted to use with Administrate.

No more.

Now, if a developer doesn't define a custom #to_s on a model,
Administrate will detect that and default to showing the object's class
and database id.

[houndci-bot]

Line is too long. [99/80]

[c-lliope]

This could also be resolved by monkey patching ActiveRecord::Base:

module ActiveRecord
  class Base
    def to_s
      "#{self.class.to_s.titleize} ##{id}"
    end
  end
end

Thoughts on which method is better?

[mike-burns]

If Kernel#to_s isn't what the user wants to see, then maybe we should define a different method. #display_name or #administrate_name or the like?

[c-lliope]

We might be able to add a method to ...Dashboard classes that presents the resource. Something like:

require "administrate/base_dashboard"

class CustomerDashboard < Administrate::BaseDashboard
  ATTRIBUTE_TYPES = {
    created_at: Field::String,
    # ...
    updated_at: Field::String,
  }

  TABLE_ATTRIBUTES = ATTRIBUTE_TYPES.keys
  SHOW_PAGE_ATTRIBUTES = ATTRIBUTE_TYPES.keys - [:name]
  FORM_ATTRIBUTES = [:name, :email]

  def display_resource(resource)
    "#{resouce.class.to_s.titleize} ##{resource.id}"
  end
end

Thoughts?

[mike-burns]

That method is asking, not telling. The main issue with that is that it requires the objects to expose their instance variables.

I'd be very comfortable seeing this in various bits of code:

def display_resource
  to_s
end

[c-lliope]

If we used a method like display_resource on the model, developers would have to define the method on objects throughout their system. At that point, I don't see much benefit to using it over using to_s directly.

I think the solution I'm most comfortable with at this point is to tell developers something like:

You will want to define #to_s on any model you want to use with Administrate, because Ruby's default #to_s does not give a consistent string between different page requests.

If you're too lazy to implement #to_s on all of your models yourself, add gem "activerecord_consistent_strings" to your Gemfile. It monkey-patches Activerecord to save you a grand total of three lines of code per class.

...then we'd need to release the activerecord_consistent_strings gem as well.

[mike-burns]

Oh I didn't understand: you want to use AR's #to_s method, and allow users to override it?

[JoelQ]

Thoughts on extracting __getobj__ to a private method? Maybe decorated_resource or similar?

[c-lliope]

@mike-burns if I understand your question, then yep!

When we need to display foo in the UI (where class Foo < ActiveRecord::Base), we're using foo.to_s.

Here's a screenshot that shows how we're using #to_s in the app, and why users need to override it:

The decision to use #to_s was originally made back in #5 - it was better than the solution at the time, of specifying a single attribute to use as the title.