Referencing objects in extended views

If you're trying to DRY up your views, you may be extending views within other views. For example, you may have an index.rabl view that just references a show.rabl view.

# index.rabl
object @rosters

extends "rosters/show"

# show.rabl
object @roster

attributes :id, :first, :last, :number, :position

However, things get tricky if you need to reference the object within your layout, to provide conditional displays of data. For example, if you have a view like this:

# show.rabl
object @roster

attributes :id, :first, :last, :number, :position

child ((@current_roster == self || @current_roster.is_manager) ? @roster.roster_telephones : @roster.roster_telephones.pub) => :telephone_numbers do
  extends "telephone_numbers/index"
end

You will find that if you visit /rosters/show, you get the information that you expect. However, if you visit /rosters/index, you will get an error about "no such method roster_telephones for nil".

This is because, unlike you may expect, the @roster object is not getting set when the show.rabl template is extended from within the index.rabl view.

Instead, according to @nesquena, you should use the node operation, which will allow you to execute a block that references the object. This code works:

# show.rabl
object @roster

attributes :id, :first, :last, :number, :position

node :telephone_numbers do |roster|
 phone_numbers = ((@current_roster == roster || @current_roster.is_manager) ? roster.roster_telephones : roster.roster_telephones.pub)
 partial("telephone_numbers/index", :object => phone_numbers)
end

This method will allow you to access the primary object in your view, no matter where it's called from.