Lift Framework example source code file (WithResourceId.scala)

This example Lift Framework source code file (WithResourceId.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

dispatchit, elem, elem, empty, empty, nodeseq, none, none, null, some, some, string, unprefixedattribute, withresourceid

The Lift Framework WithResourceId.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 builtin
package snippet


import net.liftweb.http._
import net.liftweb.common._
import net.liftweb.util._
import scala.xml._
import Helpers._

/**
 * Adds a resource id entity for each URI in order to control browser caching.
 * The rules of creating "unique" URI's are defined in LiftRules.attachResourceId function.
 * 
 * <pre>
 * <lift:with-resource-id>
 *   <link ... />
 *   <script ... />
 * </lift:with-resource-id>
 * </pre>
 */
object WithResourceId extends DispatchSnippet {
  def dispatch: DispatchIt = {
    case _ =>  render
  }


  import Helpers._

  def render(xhtml: NodeSeq): NodeSeq = {
    xhtml flatMap (_ match {
     case e @ Elem(prefix, "link", attrs, scope, childs @ _*) => 
        attrStr(attrs, "href").map ( href =>
        Elem(prefix, "link",               
             MetaData.update(attrs, 
                             scope, 
                             new UnprefixedAttribute("href", LiftRules.attachResourceId(href), Null)),
             scope, childs: _*)) openOr e
     case e @ Elem(prefix, "script", attrs, scope, childs @ _*) => 
        attrStr(attrs, "src") map (src =>
        Elem(prefix, "script", 
             MetaData.update(attrs, 
                             scope, 
                             new UnprefixedAttribute("src", LiftRules.attachResourceId(src), Null)),
             scope, childs: _*)) openOr e
     case e => e
    })
  }


  private def attrStr(attrs: MetaData, attr: String): Box[String] = (attrs.get(attr) match {
    case None => Empty
    case Some(Nil) => Empty 
    case Some(x) => Full(x.toString)
  }) or (attrs.get(attr.toLowerCase) match {
    case None => Empty
    case Some(Nil) => Empty 
    case Some(x) => Full(x.toString)
  })
}