Nested XML using REST

Rails
1

My Simulation model looks like this:
class Simulation < ActiveRecord::Base
belongs_to :user
has_many :resources
has_many :loads
has_many :distributions
has_many :buffers…

My Load model:
class Load < ActiveRecord::Base
has_many :load_dist_links
has_many :distributions, :through => :load_dist_links
belongs_to :simulation…

My Resource model:
class Resource < ActiveRecord::Base
has_many :rsc_q_links
has_many :rsc_dist_links
has_many :distributions, :through=> :rsc_dist_links
has_many :buffers, :through => :rsc_q_links
belongs_to :simulation…

http://localhost:3000/simulations/4.xml uses this show method:

def show
#@simulation = Simulation.find(params[:id])
@simulation = current_user.simulations.find(params[:id])
@resources = @simulation.resources(force_reload = true)
@distributions = @simulation.distributions(force_reload = true)
@buffers = @simulation.buffers(force_reload = true)
@loads = @simulation.loads(force_reload = true)

respond_to do |format|
  format.html # show.html.erb
  format.xml  { render :xml => @simulation.to_xml(:include=> [

:buffers, :resources, :loads, :distributions])}
end
rescue ActiveRecord::RecordNotFound => e
prevent_access(e)
end

which gives me the following XML:

<?xml version="1.0" encoding="UTF-8" ?>
  • 2008-09-10T22:15:28Z Standard Server Simulation 4 GroceryStore 8.0 hr 2008-09-10T22:15:28Z 3
  • <buffer…/>
  • <resource…/>
  • <load…/>
  • <distribution…/>
  • <distribution…/>

But what I really want is for the distribution that belongs to the
element to be nested inside that element, and the same thing for
the distribution that belongs to the element.

When I call /simulations/4/resources/2.xml or
/simulations/4/loads/1.xml, I get what I want because I can use :include
on the to_xml statement. But everything I’ve tried in the
simulations_controller show method, changing the simulation model, even
messing with routing, gives me errors.

For example, I have tried

def show
#@simulation = Simulation.find(params[:id])
@simulation = current_user.simulations.find(params[:id])
@loads = @simulation.loads(force_reload = true)
@resources = @simulation.resources(force_reload = true)
@load_distributions = @loads.distributions(force_reload = true)
@rsc_distributions = @resources.distributions(force_reload = true)
@buffers = @simulation.buffers(force_reload = true)

respond_to do |format|
  format.html # show.html.erb
  format.xml  { render :xml => @simulation.to_xml(:include=> [

:buffers, :resources, :loads, :load_distributions, rsc_distributions])}
end
rescue ActiveRecord::RecordNotFound => e
prevent_access(e)
end

but the error is "undefined method “distributions” for the line
@[email protected](force_reload = true).

How can I modify the simulations_controller#show method so that I get
the distributions associated with loads and/or resources to be properly
nested?

LG