Software Engineering Aspects of Web Based Development

Cathy HuttenhoffSoftware Engineer

Senior Seminar Fall 2009

Abstract

Initially there was no need for web development because there was no such thing as the internet. But as this was created, the need for a new form of development grew. This form of development corresponded to the new form of programming. In order for a program to be written using software engineering, it must follow a software development process. There are several processes to choose from and each is different. The processes used to create web pages and web applications are similar to the ones that were originally used to develop other programs but have crucial differences including software security, load issues and security.

Overview

Background Concurrency Unpredictable Load Security Multi-Modal Interface Software Engineering Process

Background

Internet Grew to popularity in the 1990s

Old model didn't take into account new demands

New demands Concurrency Unpredictable loads Security Multi-Modal Interface

Concurrency

Originally only one user at a time. Some lag acceptable. Only a few commands at a time. Now many users at once. Users demand less lag time. Now the few commands multiplied by many

users.

Unpredictable Load

Websites don't know how many viewers/users they will have.

Could have 100 today And 100,000 tomorrow

System must be able to handle loads of any size.

Visitor count Int overflow

Twitpocalypse

Security

Physical access vs. Remote Access Malicious Programs

Virus Worms Spyware

Microsoft Windows Release patches for security

Financial Transaction Don't want personal information stolen.

Multi-Modal Interface

“Multimodal interfaces process two or more combined user input modes, such as speech, pen, touch, manual gestures, and gaze, in a coordinated manner with multimedia system output.”

People want more technology. People want to be able to do more on their

technology. Web pages on Blackberries & Cell

Phones

Software Engineering Process

Requirements Design Implementation Verification / Testing Maintenance

Figure 1 : Waterfall Method

Requirements

Speed Concurrency Different numbers of users User Interface

Purchaser of software will be especially concerned about this.

Design

Low coupling Different parts of a system Different pages of a website

Store information on users computer vs. in master database

Independent parts using cookies

Cookies

In computing, a cookie is a small piece of text stored on a user's computer by a web browser.

A cookie consists of one or more name-value pairs containing bits of information such as user preferences, shopping cart contents, the identifier for a server-based session, or other data used by websites.

It is sent by a web server to a web browser and then sent back unchanged by the browser each time it accesses that server.

Implementation

Transforming diagrams into the base code. Create a Graphical User Interface (GUI)

Put code a methods into that page Post back vs not post back

Web development environment vs by hand Visual Studios .Net DreamWeaver

Testing

Black box vs. White box Easier to test

Beta versions Open up to users Get public to do testing Only need an internet connection No special software to install

Good bug tracking system Online

Maintenance

Easier to offer tech. support Only one version Don't have to support multiple versions

Easier to fix bugs When a bug fix is found, then the page is

updated Don't have to wait for the next patch release

date

Conclusion New Demands

Concurrency Unpredictable Load Security Multi-Modal Interface

Software Engineering Process Requirements Design Implementation Verification / Testing Maintenance

Questions?

[1] Greenspun, P. (2003). Software Engineering for Internet Applications (6.171). Retrieved (2009, October 16) from http://philip.greenspun.com/teaching/one-term-web

[2] Software Development Process. Wikipedia : the free encyclopedia. Retrieved (2009, October 16) from http://en.wikipedia.org/wiki/File:Waterfall_model.png

[3] Siegler, M. G. (2009). Twitter moves up the twitpocalypse. all hell may break loose today.. TechCrunch, Retrieved from http://www.techcrunch.com/2009/06/12/all-hell-may-break-loose-on-twitter-in-2-hours/

[4] (2009). Multimodal Interfaces. In Encyclopedia Britannica. Encyclopedia Britannica. Retrieved October 20, 2009, from http://encyclopedia.jrank.org/articles/pages/6843/Multimodal-Interfaces.html

[5] Mikio Aoyama, "Web-Based Agile Software Development," IEEE Software, vol. 15, no. 6, pp. 56-65, Nov./Dec. 1998, doi:10.1109/52.730844

References