Lift Framework example source code file (ResourceServer.scala)

This example Lift Framework source code file (ResourceServer.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Lift Framework tags/keywords

boolean, box, chash, date, expires, list, list, long, long, net, network, nil, nil, partialfunction, partialfunction, string, threading, threads

The Lift Framework ResourceServer.scala source code

/*
 * Copyright 2007-2011 WorldWide Conferencing, LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.liftweb
package http

import net.liftweb.common.{Box, Full, Empty}
import net.liftweb.util._
import Helpers._
import java.net.{URL, URLConnection, JarURLConnection}
import java.util.concurrent.{ConcurrentHashMap => CHash}

object ResourceServer {
  var allowedPaths: PartialFunction[List[String], Boolean] = {
    case "jquery.js" :: Nil => true
    case "yui" :: _ => true
    case "liftYUI.js" :: Nil => true
    case "extcore" :: _ => true
    case "liftExtCore.js" :: Nil => true
    case "json2.js" :: Nil => true
    case "json.js" :: Nil => true
    case "jlift.js" :: Nil => true
    case bp@("blueprint" :: _) if bp.last.endsWith(".css") || bp.last.endsWith(".png") => true
    case "jquery-autocomplete" :: "jquery.autocomplete.js" :: Nil => true
    case "jquery-autocomplete" :: "jquery.autocomplete.css" :: Nil => true
    case "jquery-autocomplete" :: "indicator.gif" :: Nil => true
  }

  private def rewriter = new PartialFunction[List[String], List[String]]{
    def isDefinedAt(in: List[String]) = LiftRules.jsArtifacts.pathRewriter.isDefinedAt(in)

    def apply(in: List[String]): List[String] = LiftRules.jsArtifacts.pathRewriter(in)
  }

  @volatile var pathRewriter: PartialFunction[List[String], List[String]] = rewriter orElse {
    case "json.js" :: Nil => List("json2-min.js")
    case "json2.js" :: Nil => List("json2-min.js")
    case xs => xs
  }

  /**
   * The base package for serving resources.  This way, resource names can't be spoofed
   */
  var baseResourceLocation = "toserve"

  private val lastModCache: CHash[String, Long] = new CHash()

  def calcLastModified(in: URL): Long = {
    val str = in.toString
    if (!Props.devMode && lastModCache.containsKey(str)) lastModCache.get(str)
    else {
      val ret: Long =
      (for{
        uc <- tryo(in.openConnection)
      } yield {
          uc.getLastModified match {
            case 0L => uc match {
              case jc: JarURLConnection => jc.getJarEntry() match {
                case null => 0L
                case e => e.getTime()
              }
              case _ => 0L
            }
            case x => x
          }
        }) openOr 0L
      lastModCache.put(str, ret)
      ret
    }
  }


  def findResourceInClasspath(request: Req, uri: List[String])(): Box[LiftResponse] =
    for{
      auri <- Full(uri.filter(!_.startsWith("."))).filter(auri => isAllowed(auri))
      rw = baseResourceLocation :: pathRewriter(auri)
      path = rw.mkString("/", "/", "")
      url <- LiftRules.getResource(path)
      lastModified = calcLastModified(url)
    } yield
      request.testFor304(lastModified, "Expires" -> toInternetDate(millis + 30.days)) openOr {
        val stream = url.openStream
        val uc = url.openConnection
        StreamingResponse(stream, () => stream.close, uc.getContentLength,
          (if (lastModified == 0L) Nil else
            List("Last-Modified" -> toInternetDate(lastModified))) :::
                  List("Expires" -> toInternetDate(millis + 30.days),
                       "Date" -> Helpers.nowAsInternetDate,
                       "Pragma" -> "",
                       "Cache-Control" -> "",
                       "Content-Type" -> detectContentType(rw.last)), Nil,
          200)
      }


  /**
   * detect the Content-Type of file (path) with context-defined content-types
   * (application's web.xml or container's configuration), and fall
   * back to system or JVM-defined (FileNameMap) content types.
   * if no content-type found, then return "application/octet-stream"
   *
   * @param path Resource name to be analyzed to detect MIME type
   *
   * @see HTTPContext # mimeType ( String )
   * @see URLConnection # getFileNameMap ( )
   */
  def detectContentType(path: String): String = {
    // Configure response with content type of resource
    (LiftRules.context.mimeType(path) or
            (Box !! URLConnection.getFileNameMap().getContentTypeFor(path))) openOr
            "application/octet-stream"
  }

  private def isAllowed(path: List[String]) = allowedPaths.isDefinedAt(path) && allowedPaths(path)

  def allow(path: PartialFunction[List[String], Boolean]) {
    allowedPaths = path orElse allowedPaths
  }

  def rewrite(rw: PartialFunction[List[String], List[String]]) {
    pathRewriter = rw orElse pathRewriter
  }
}