Monday, 16 April 2007

Learn to Develop State-enabled Applications with PHP

Sometimes while a user is browsing a web site and surfing from one web page to another, the web site needs to remember the actions performed by the user. In other words, the web site needs to remember the state that is the selected items of the user's browsing activities. However, HTTP is a stateless protocol and is ill equipped to handle states. John L teaches you how to develop state-enabled applications with PHP.

He explains that a standard HTML web site basically provides information to the user and a series of links that directs the user to other related web pages. This stateless nature of HTTP allows the web site to be replicated across many servers for load balancing purposes. A major drawback is seen when while browsing from one page to another, the web site does not remember the state of the browsing session. This makes interactivity almost impossible, he says.

So, in order to increase interactivity, the developer can use the session handling features of PHP to augment the features of HTTP to remember the state of the browsing session. There are two ways PHP does this, which he states as follows:

• Using cookies
• Using Sessions