Scala Liftweb : Re render page element without making any request to the server

Table of contents
Reading Time: 2 minutes

Lift introduces a powerful feature that enables developer to create rich interactive application using Comet and Ajax support . Using Comet , its easy to push content from server to browser by sending request asynchronously . AJAX works for a single client at a time , while Comet works for multiple users . Comet works like AJAX but in opposite direction .

In this blog , I am explaining how to re render a page element without making any request to server with no extra AJAX request , no page refreshes , nothing . As you can see in Gmail online Email portal , when an email is send by a user , receiver’s inbox is automatically gets updated and new email appears on receiver’s inbox .

Let’s take a look at a simple example . I am assuming that you are aware with basic Lift’s configuration . In this example , we are going to build a Notification snippet where client page is getting updated by server with current notification every 10 seconds .

In HTML file :

Now we are going to defined our comet actor by creating CometNotification class and extending CometActor :

Your Comet Actor !!

Current Time: Updates Messages 11 Feb, 2013 6:16:50 PM

Here time would be updated after every ten seconds .

Code base for the current example can be found on the Knoldus GitHub account here :

This is a simple example which will give the basic idea of Comet . You can build more complex application using Comet , such as chat application , Display notification like Facebook .

Written by 

Ayush is the Sr. Lead Consultant @ Knoldus Software LLP. In his 10 years of experience he has become a developer with proven experience in architecting and developing web applications. Ayush has a Masters in Computer Application from U.P. Technical University, Ayush is a strong-willed and self-motivated professional who takes deep care in adhering to quality norms within projects. He is capable of managing challenging projects with remarkable deadline sensitivity without compromising code quality.