Polymorphic partials

[netwire88]

I have a data model where a User can like a Project, Suggestion, Comment, or other objects.
The models are set up correctly, and likes/show.rabl works if we were just to support the Project child

object @like
attributes :id, :created_at, :target_type, :target_id, :user_id
child :user => :user do
  extends "users/show"
end
child :target do
  node do |project|
    partial('projects/show', :object => project)
  end
end

However, I want to be able to use partials of suggestions/show, comments/show as well depending on target_type.

I tried this but it's not working:

child :target do |u|
  u.target.map do |r|
    if r.is_a?(Suggestion)
      partial("suggestions/show", :object => r)
    elsif r.is_a?(Project)
      partial("projects/show", :object => r)
    end
  end
end

I get undefined method target for <Rabl::Engine:0x69fb988>. However, I don't get this error in the first case. Any ideas?

[databyte]

So child doesn't work with blocks the same way node does. Node calls the block explicitly to merge in the return whereas child traverses the object namespace.

object @foo         # root_object is @foo

child :target do    # root_object is now @foo.target
  attribute :bar    # comes from @foo.target.bar
end

node :hello do |hi| # root_object is still @foo
  hi.bar            # comes from @foo.bar
end

What you probably want is to leave your child the way it was but within node, do your if/else checks.

child :target do
  node do |project|
    if project.is_a?(Suggestion)
      partial("suggestions/show", :object => project)
    elsif project.is_a?(Project)
      partial("projects/show", :object => project)
    end
  end
end

(or something like that)

[netwire88]

Thank you databyte, that worked very well.

This is what I ended up using:

child :target do
  node do |r|
    if r.is_a?(Suggestion)
      partial("suggestions/show", :object => r)
    elsif r.is_a?(Project)
      partial("projects/show", :object => r)
    end
  end
end