W3C Lib Architecture

The Protocol Object

The Core Library doesn't know anything about protocol modules. This has the big advantage that an application can register any number of protocols including access to the local file system. The Library core is independent of whether you make an application capable of speaking all known Internet protocols or only can access, for example a HTTP server - to the Library it's all a set of callback functions.

The Protocol object handles two types of callback functions: one for a client application and one for a server application. This means that you can register not only any type of protocol clients but also their server counterparts. Whether it is a client module or a server module, a protocol module is identified by an access scheme which is identical to the access scheme known from the URL syntax, for example

	http://www.w3.org
	ftp://ftp.w3.org
	etc.
The User's Guide describes in detail how you can set up the protocol modules in your application.


Henrik Frystyk, libwww@w3.org, December 1995