Question

I have two models where A has_many B. If I load A including associated B as such:

a = A.find(:first, include: :bs)

a.inspect only shows the attributes of a:

 => "#<A id: 1, name: \"Test\", created_at: \"2012-07-02 21:50:32\", updated_at: \"2012-07-02 21:50:32\">"

How can I do a.inspect such that it displays all associated a.bs?

Answer 1

You can’t do that by default. It might create too many problems and side effects with inspecting objects. However you could extend inspect yourself with something like this:

class A < ActiveRecord::Base
  ...
  def inspect
    [super, bs.inspect].join("\n")
  end
end

Note though that that’s not very clever, since it will force the loading of bs every time you inspect an A instance. So maybe you want to be smarter and do something like this:

def inspect
  [super, bs.loaded? ? bs.inspect : nil].compact.join("\n")
end

This will only inspect bs if it’s already preloaded (with :include for example).

Or maybe you want to create a super_inspect instead that does everything automatically. You could extend ActiveRecord::Base with something like:

class ActiveRecord::Base
  def deep_inspect
    ([inspect] + self.class.reflect_on_all_associations.map { |a|
      self.send(a.name).inspect
    }).compact.join("\n  ")
  end
end

This will automatically look up all the associations with reflect_on_all_associations, and if the association is loaded it will call inspect on that.

Now you can modify the above code however you want to create your own customized inspect, or just extend the current inspect if you like. Anything is possible with a little bit of code.

Here is an example of an updated version that is a bit smarter:

class ActiveRecord::Base
  def deep_inspect
    ([inspect] + self.class.reflect_on_all_associations.map { |a|
      out = ""
      assoc = self.send(a.name)
      # Check for collection
      if assoc.is_a?(ActiveRecord::Associations::CollectionProxy)
        # Include name of collection in output
        out += "\n#{assoc.name.pluralize}:\n"
        out += self.send(a.name).to_a.inspect
      else
        out += self.send(a.name).inspect
      end
      out
    }).compact.join("\n  ")
  end
end