Conclusion

Using PHP, we have created a simple XML parser on the server. In doing so we went beyond the simple DOM parser and learned event-driven techniques. Our parser read in a simple XML file and generated a response.

On the client side, too, we are now able to both read and write XML. We can even use the XML.sendAndLoad() function, which exchanges the XML object in memory with the server. A two-way XML data exchange is functioning smoothly: Both sides can receive, alter, and retransmit an XML object. We can design all sorts of data-sharing strategies, both symmetrical and assymetrical.

We have also been introduced to a powerful tool, loved by hackers and network security professionals. Packet sniffers are of great value to any developer creating sophisticated Internet applications. A packet sniffer is a fine instrument with which we can examine in a living software system and in minute detail the processes of request and response that we learned as academic abstractions.