call (Rack::URLMap)

    # File lib/rack/urlmap.rb, line 36
        def call(env)
          path = env["PATH_INFO"].to_s.squeeze("/")
          script_name = env['SCRIPT_NAME']
          hHost, sName, sPort = env.values_at('HTTP_HOST','SERVER_NAME','SERVER_PORT')
          @mapping.each { |host, location, app|
            next unless (hHost == host || sName == host \
              || (host.nil? && (hHost == sName || hHost == sName+':'+sPort)))
            next unless location == path[0, location.size]
            next unless path[location.size] == nil || path[location.size] == ?/

            return app.call(
              env.merge(
                'SCRIPT_NAME' => (script_name + location),
                'PATH_INFO'   => path[location.size..-1]))
          }
          [404, {"Content-Type" => "text/plain"}, ["Not Found: #{path}"]]
        end