CSC/ECE 517 Fall 2014/ch1a 4 wl

WEB DEVELOPMENT USING LIFT

Lift Web Framework

Components

1. LiftCore: This is the web processor of the framework which handles the following functions.
   1. Request/Response
   2. Rendering Pipeline
   3. Invoking User Functions
2. LiftRules : Lift Configuration
3. LiftSession: Inherent Session State.
4. S: stateful context for request/response lifecycle.
5. SiteMap: contains web pages for the lift application.
6. SHtml: helper functions for XHtml.
7. Views: Views as XML content. Allows composing views from not only html files but other contexts too.
8. LiftResponse: Abstraction of response sent to the client.
9. Comet: allows sending asynchronous content to browser.
10. ORM: A specialized library.
11. HTTP Auth: provides control over authentication model.
12. JS API: JavaScript abstraction layer.<ref name=explore>Exploring Lift Framework</ref>

Getting Started

Set Up on Eclipse

1. Download “Scala IDE for Eclipse” : http://scala-ide.org/
2. Install plugin in Eclipse from this update site : http://download.scala-ide.org/sdk/helium/e38/scala211/stable/site
3. Once the plugin is installed restart Eclipse
4. Install sbteclipse by adding the following to projects/plugins.sbt in your Lift Project: addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "2.5.0")
5. You can then create Eclipse project files (.project and .classpath) by entering the following into the SBT prompt: eclipse <ref name=cookbook>The Lift Cookbook</ref>

Basic Web Application Structure

Step 1: Making a SiteMap entry

Every page on the site needs a SiteMap entry.

def sitemap(): SiteMap = SiteMap(
  Menu("Home") / "index",
  Menu("Second Page") / "second"
)

Step 2: Creating the view

Create an HTML file that corresponds to the sitemap entry.

<meta content="text/html; charset=UTF-8" http-equiv="content-type">
    <title>Home</title>
   
   
    <div id="main" class="lift:surround?with=default&at=content">
      <div>
        Hi, I'm a page that contains the time:
        <span class="lift:TimeNow">??? some time</span>.
      </div>

      <div>
        And a button: <button class="lift:ClickMe">Click Me</button>.
      </div>
    </div>

Step 3 : Creating the Snippet

A snippet can be thought of as a controller which has rules for transforming the section of your template.

package code
package snippet

import net.liftweb._
import util._
import Helpers._

object TimeNow {
  def render = "* *" #> now.toString
}

<ref name=simplylift>Simply Lift</ref>

Advantages

1. Built on Scala which is a powerful functional language.
2. Multiple Component support : Divides the controls into snippets which can be used together on a single page thereby not coupling a page with a controller.
3. CSS Binding : allows to navigate the HTML Dom tree.
4. Native Javascript/Ajax Support
5. Out-of-box Security.
6. Lazy Loading & Parallel Page rendering : Lift shows automatic spinners on area still being loaded, components are able to load over multiple thread at the same time.<ref name=benefits>Why Lift Webframework is my favorite.</ref>

Disadvantages

1. Lots of state kept in session.
2. Learning Curve as no more MVC.

<ref name=quora>Comparison on Quora</ref>

References

<references></references>