Building WML Gadgets: Phone Message Application

Friday Jan 31st 2003 by Steve Schafer

Not all wireless applications have to be super-applications. Some of the best wireless applications perform simple tasks to improve wireless functionality. Learn how to build a simple, single-purpose gadgets that can aid the user of a mobile phone.

This series of articles describes how to provide Webcontent to mobile devices through WML (Wireless Markup Language). This articlecovers creating an application to aid the user of a mobile phone.

Note: These articles cover WML and WMLScript version 1.1,which are supported by the majority of mobile devices in use today. Thearticles assume a working knowledge of HTML and general Web technologies, andfurther assume that you have read the previous article(s) in this series.

Simple Applications

Not all wireless applications have to be super-applications.Some of the best wireless applications perform simple tasks to improve wirelessfunctionality. The last few articles in this series have shown how simple,single-purpose gadgets can boost the functionality of mobile devices. Thisarticle will present a slightly more complex application in the same"extending functionality" vein.

The Application

This article will cover how to build a simple phone messageapplication. Although we live in a time of portable phones, intelligentvoicemail, and other electronic telephone magic, there are still times whenmessages are taken by one person (operator) and passed to others (recipients).For example, consider a businessman who often travels outside the home office.Many of his customers and contacts may occasionally call the home office andleave messages with his secretary. Using a simple Web form, the secretary canpass the message to the businessman's cell phone, where he can review themessage and even return the call with the simple press of a button.

Application Specifications

This application will utilize the following components:

  • A simple HTML form to input the message
  • A flat-file database to store the messages
  • A CGI script to access the database

Essentially, the application operates as shown in thefollowing diagram:

FIGURE 1 - Our application's design. The operator uses a Webform to send the data to a CGI script that stores the data in a database. Thesame script is used by a mobile user (recipient) to access that data.

We'll use Perl for the CGI script, for the same reasonswe've used it previously: It's available for most platforms and extensibleenough to perform almost any task necessary.

Note: As with previous articles, teaching Perl is out of thescope of this series. There are numerous sources on the Internet for learningPerl, including the tutorial at