Oracle Web Applications: PL/SQL Developer's Intro

Server-to-Client Communication

The Internet (or an intranet) is a network that links different computers together. Before we can start writing web applications, we must understand how the output from these systems actually gets from the server to the browser, which means that we have to learn a little about how the Internet and the Web work.

OAS and WebDB use standard Internet conventions and protocols to send resources to a client. The most important parts of this interchange are:

• A TCP/IP network to connect the server to the client

• A software communication port to serve as a collection point for incoming requests

• A transfer protocol called HTTP to govern how server and client communicate

• A client program called a web browser to allow users to request and receive resources from the OAS or WebDB server

• A uniform resource locator (URL) to allow the browser to find a particular resource

• A MIME type to tell the browser what to do with resources once received from the OAS or WebDB server

The following sections briefly describe each of these parts.

The TCP/IP Network

Browsers connect to an OAS or WebDB server using the TCP/IP networking protocol. Although there are a number of different types of networking protocols, such as DECNet or IPX, web systems only work with TCP/IP. Fortunately, more and more operating systems have this functionality built in, including Unix, Windows 95, Windows 98, Windows NT, OS/2, and Linux.

Every machine on a TCP/IP network is identified by a four-part IP ...