draft of Rack request verifier

middleware_dummycode.rb

require 'rubygems'
require 'rack'

class Rack
  class PlayCo
    class RequestValidator
      
      # ==== Parameters
      # app<Rack::Builder>:: The Rack builder which will use this middleware.
      # path_opts<Hash>:: Path options used to identify path to validate.
      #
      # ==== Options (path_opts)
      # :http_method<Array, String>::
      #   'POST', 'GET', 'DELETE' or 'UPDATE' HTTP verb used against 
      #   env['REQUEST_METHOD'].
      # :format<Array, String>::
      #   'xml', 'html', 'json', etc - what to test against
      # :salt<String>::
      #   secret salt used to hash the request
      #
      # ==== Examples
      #
      #  (Rails 2.x) in RAILS_ROOT/config.ru:
      #   use Rack::PlayCo::RequestValidator :http_method => ['POST'], 
      #                                      :format => ['xml']
      def initialize(app, path_opts)
       @app = app
       # TODO validate the path_opts and/or set defaults
       # Accept either a single string or Array for methods/formats
       @path_opts = path_opts
      end

     def call(env)
       if specified_request_method?(env) && specified_format?(env)
         if valid_request?(env)
           @app.call(env)
         else
           # IMPORTANT: Must set content-type to same type we received,
           # and send back a message detailing the error (HMAC? UUID?)
           [400, {"Content-Type" => "text/html"}, [post_body]]
         end
       end
     end
     
     def specified_request_method?(env)
       @path_opts[:http_method].include?(env['REQUEST_METHOD'])
     end

     def specified_format?(env)
       @path_opts[:format].include?(env['REQUEST_METHOD'])
     end

     def valid_request?(env)
       salt = @path_opts[:salt] || DEFAULT_SALT

       #
       # Need to insert all of the logic from lib/client_verifier.rb here,
       # specifically the verify_client_hmac() method
       #

       post_body = env['rack.input'] ? env['rack.input'].read : nil

     end
   end
 end
end