The internet and the World Wide Web are woven into our daily lives so intricately that life without them is unimaginable. We use the web for our daily news, to finding directions(maps), socializing(Facebook), sending/receiving emails, and buying e-tickets and books over e-retail stores on the net. With a click, a drag and drop or by just moving the mouse over a web page we see results instantaneously. But what are the technologies that power the Web outside of the routers and hubs of the data communication world?
Actually if one peeks into the technologies that power Web 2.0 one would be amazed at the bewildering array of technological choices that one is confronted with. My curiosity was whetted when I found that there were so many possibilities that go behind different websites from Gmail, http://www.amazon.com. Twitter, Facebook or maps.yahoo.com.
This article tries to give a bird’s eye view of the different technologies at the different layers. In many ways this article will be more of name dropping of the technologies rather than doing any real justice to each individual piece. I am merely presenting the different technologies as an interested spectator rather than as a web expert.
Presentation Layer: This is the layer which presents the web page to user. In the presentation layer most of the pages are made of elements of from HTML,CSS, PHP, Javascript, AJAX. These are diferent scripting mechanisms to display or take input from the user. Subsequently there arose the need for technologies called Rich Internet Application (RIA) to provide a much more superior user experience. These technologies are used to display video content and animations. Hence, we have Flash, Flex to more sophisticated technologies like Liferay, Primefaces, Myfaces and Java Server Faces (JSF) to the current HTML5. These technologies allow for drag-and-drop functionality, incorporating videos and animations in the web pages making the user experience similar to what he experiences on the desktop.
Enterprise Layer: At this layer the user input is processed and the client makes necessary requests to the back end server to get the appropriate results. This layer also there is a virtual explosion of technologies that make this possible. In this layer from the earlier C++, Java programs the movement was towards Enterprise Java Beans (EJB) invoked through servlets or Java Server Pages. To make the life of the web developer easier (?) there are several web frameworks that automate some of the common tasks of the developer. Some of them are Django with Python, Ruby on Rails (RoR), Groovy Grails, Perl-Catalyst, Python-Flask and so on. Each web framework has it pros and cons and has different learning curves. While Python developers thrive on “there is only one way to do a thing”, die-hard Ruby developers believe in the “do not repeat yourself (DRY)” philosophy. So the technology choice will be a matter of taste combined with deadlines for the project.
Persistence Layer: At the persistence layer there is Hibernate which converts a relational model to an object model and vice-versa making it easy to manipulate the rows and columns of tables. Usually this layer is coupled with Spring frameworks. Another competing technology is Struts framework.
Database Layer: While Hibernate can be used as a persistence layer it is also possible to access the database through ODBC, JDBC etc.
Exchange of Data: In the earlier days sending and receiving data or invoking remote procedure calls were through CORBA or RPC (Remote Procedure Calls). Subsequently other methods have been implemented for data exchange between servers. They are XML, JSON (Javascript Object Notation),SOAP (Simple Object Access Protocol) to the more current REST (Representational State Transfer)
Hence there are plethora of choices to make prior in the design of web sites complete with back end processing. The choices that are made will depend on the look and feel of the web site coupled with the ease of implementation of the site given the project deadlines.
Giga thoughts ... 