Lift Framework example source code file (Embed.scala)

This example Lift Framework source code file (Embed.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

discard, dispatchit, dispatchsnippet, embed, fix, fix, map, me, me, nodeseq, nodeseq, none, none, snippetexecutionexception

The Lift Framework Embed.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 scala.xml._
import net.liftweb.http._
import net.liftweb.util._
import net.liftweb.common._

import Box._

/**
 * This object implements the logic for the <lift:embed> tag. It
 * supports retrieving a template based on the "what" attribute, and
 * any <lift:bind-at> tags contained in the embed tag will be used
 * to replace <lift:bind> tags within the embedded template.
 */
object Embed extends DispatchSnippet {
  private lazy val logger = Logger(this.getClass)

  def dispatch : DispatchIt = {
    case _ => render _
  }

  def render(kids: NodeSeq) : NodeSeq =
  (for {
      ctx <- S.session ?~ ("FIX"+"ME: session is invalid")
      what <- S.attr ~ ("what") ?~ ("FIX" + "ME The 'what' attribute not defined")
      templateOpt <- ctx.findTemplate(what.text) ?~ ("FIX"+"ME the "+what+" template not found")
    } yield (what,LiftSession.checkForContentId(templateOpt))) match {
    case Full((what,template)) => {
      val bindingMap : Map[String,NodeSeq] = Map(kids.flatMap({
        case p : scala.xml.PCData => None // Discard whitespace and other non-tag junk
        case t : scala.xml.Text => None // Discard whitespace and other non-tag junk
        case e : Elem if e.prefix == "lift" && e.label == "bind-at" => {
          e.attribute("name") match {
            /* DCB: I was getting a type error if I just tried to use e.child
             * here. I didn't feel like digging to find out why Seq[Node]
             * wouldn't convert to NodeSeq, so I just do it with fromSeq. */
            case Some(name) => Some(name.text -> NodeSeq.fromSeq(e.child))
            case None => logger.warn("Found <lift:bind-at> tag without name while embedding \"%s\"".format(what.text)); None
          }
        }
        case _ => None
      }): _*)

      BindHelpers.bind(bindingMap, template)
    }
    case Failure(msg, _, _) => throw new SnippetExecutionException(msg)

    case _ => throw new SnippetExecutionException("session is invalid")
  }

}