gistfile1.rb

#config/routes.rb 
ActionController::Routing::Routes.draw do |map|
  map.resources :chatters do |chatter|
    chatter.resources :chats
  end


#app/controllers/chats_controller.rb 
#Parameters: {"chat"=>{"id"=>"1", "message"=>"cool"}}
class ChatsController < ApplicationController
  # GET /chats
  # GET /chats.xml
  def find_by_id
    logger.info "The params Id is #{params['chat']['id']}"
    @chats = Chat.find(:first, :conditions => {:id => params["chat"]["id"] })

    respond_to do |format|
      #format.html # index.html.erb
      format.xml  { render :xml => @chats.id }
    end
  end

#app/controllers/chatters_controller.rb
#Parameters: {"chatter"=>{"name"=>"second_chatter"}}
class ChattersController < ApplicationController
  # GET /chatters
  # GET /chatters.xml
  def find_by_name
    logger.info "The params Id is #{params['chatter']['name']}"
    @chatters = Chatter.find(:first, :conditions => {:name => params["chatter"]["name"] })

    respond_to do |format|
      #format.html # index.html.erb
      format.xml  { render :xml => @chatters.id }
    end
  end