Avoiding JS and CSS Caching in a way that allows serving of non-lift resources

CustomResourceId.scala

import net.liftweb.util.{NamedPF, Helpers}
import net.liftweb.http._
import net.liftweb.http.RewriteRequest
import net.liftweb.http.ParsePath
import java.io.File._
object CustomResourceId {

  val suffixes = List("css", "js")

  def init() : Unit = {
    // The random number we're using to avoid caching
    val resourceId = Helpers.nextFuncName

    // Prefix with-resource-id links with "/cache/{resouceId}"
    LiftRules.attachResourceId = (path: String) => {
      val extension = (path.lastIndexOf("."), path.lastIndexOf("?")) match {
        case (pos, pos2) if(pos2 > pos && pos > 0) => path.substring(pos + 1, pos2)
        case (pos, pos2) if(pos > 0) => path.substring(pos + 1)
        case _ => ""
      }
      if(suffixes.contains(extension)) {
        "/cache/" + resourceId + path
      } else {
        path + (if (path contains ("?")) "&" else "?") + resourceId + "=_"
      }
    }

    suffixes.foreach{ s =>
      LiftRules.statelessRewrite.prepend {
        case RewriteRequest(ParsePath("cache" :: `resourceId` :: file, `s`, _, _), _, _) => {
          RewriteResponse(file, s)
        }
      }
      LiftRules.statelessDispatch.prepend {
        case Req(`s` :: file :: Nil, `s`, _) =>
          () => for (in <- LiftRules.getResource(separator + s + separator + file + "." + s).map(_.openStream))
          yield {
            StreamingResponse(in, () => in.close, size = -1,
              headers = Nil,  cookies = Nil, code=200)
          }
      }
    }
  }
}