Lift Framework example source code file (Form.scala)

This example Lift Framework source code file (Form.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, dispatchsnippet, elem, elem, form, full, nodeseq, nodeseq, string, text, text, topscope, unprefixedattribute, unprefixedattribute

The Lift Framework Form.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 Helpers._

/**
 * This object is the default handler for the <lift:form> tag, which
 * is used to perform AJAX submission of form contents. If the "onsubmit"
 * attribute is set on this tag, then the contents there will be run prior
 * to the actual AJAX call. If a "postsubmit" attribute is present on the
 * tag, then its contents will be executed after successful submission of
 * the form.
 */
object Form extends DispatchSnippet {

  def dispatch : DispatchIt = {
    case "render" => render _
    case "ajax" => render _
    case "post" => post _
  }

  /**
   * Add the post method and postback (current URL) as action.
   * If the multipart attribute is specified, set the enctype
   * as "multipart/form-data"
   */
  def post(kids: NodeSeq): NodeSeq = {
    // yeah it's ugly, but I'm not sure
    // we could do it reliably with pattern matching
    // dpp Oct 29, 2010
    val ret: Elem = 
      if (kids.length == 1 && 
          kids(0).isInstanceOf[Elem] && 
          (kids(0).prefix eq null) &&
          kids(0).label == "form") {
            val e = kids(0).asInstanceOf[Elem]
            val meta = 
              new UnprefixedAttribute("method", "post",
                                      new UnprefixedAttribute(
                                        "action", S.uri,
                                        e.attributes.filter {
                                          case up: UnprefixedAttribute =>
                                            up.key != "method" && up.key != "action"
                                          case x => true
                                        }))
            new Elem(null, "form", meta , e.scope, e.child :_*)
          } else {
            <form method="post" action={S.uri}>{kids}
          }
    
    S.attr("multipart") match {
      case Full(x) if Helpers.toBoolean(x) => ret % ("enctype" -> "multipart/form-data")
      case _ => ret
    }
  }
  

  def render(kids: NodeSeq) : NodeSeq = {
    // yeah it's ugly, but I'm not sure
    // we could do it reliably with pattern matching
    // dpp Oct 29, 2010
    if (kids.length == 1 && 
        kids(0).isInstanceOf[Elem] && 
        (kids(0).prefix eq null) &&
        kids(0).label == "form") {
      new Elem(null, "form", addAjaxForm , TopScope, kids(0).child :_*)
    } else {
      Elem(null, "form", addAjaxForm, TopScope, kids : _*)
    }
  }

  private def addAjaxForm: MetaData = {
    val id = Helpers.nextFuncName

    val attr = S.currentAttrsToMetaData(name => name != "id" && name != "onsubmit" && name != "action")

    val pre = S.attr.~("onsubmit").map(_.text + ";") getOrElse ""

    val post = S.attr.~("postsubmit").map("function() { " + _.text + "; }")

    val ajax: String = pre + SHtml.makeAjaxCall(LiftRules.jsArtifacts.serialize(id), AjaxContext.js(post)).toJsCmd + ";" + "return false;"

    new UnprefixedAttribute("id", Text(id),
                            new UnprefixedAttribute("action", Text("javascript://"),
                                                    new UnprefixedAttribute("onsubmit", Text(ajax), attr)))
  }
}