Distributed Objects and the World Wide Web

Multi-page version

• Overview
• Status
• The benefits

ANSA is building a set of tools to integrate a distributed object model into WWW. The objective is to provide a CORBA based environment from which the web appears to consist of a world of distributed CORBA objects. Also we want to exploit CORBA's integration capability to integrate existing information systems into WWW.

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Overview

This work uses the CORBA Internet Inter-ORB Protocol (IIOP) which will be mandatory for all CORBA 2.0 compliant platforms. The initial phase of the project is to build an infrastructure consisting of:

• An IIOP to HTTP gateway which allows CORBA clients to access Web resources
• An HTTP to IIOP gateway which allows WWW clients to access CORBA resources
• A web server which makes it resource available by both IIOP and HTTP
• Web browsers which can use IIOP as their native protocol

Within CORBA, clients will be able to invoke CORBA services and the ORB (Object Request Broker) will locate and invoke the right service. If the service is outside the CORBA world, access will take place via the IIOP to HTTP gateway (this gateway will also convert from IIOP to other protocols such as FTP); the remote object will look like a CORBA object to the CORBA client (URL's look like CORBA objects).

Clients outside the CORBA world will see CORBA objects as web objects and will be able to direct HTTP requests to these objects through the HTTP to IIOP gateway.

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Status

Initial versions of the HTTP to IIOP and IIOP to HTTP gateways are running. Modified versions of the new Arena browser (from W3C) and the Line Mode browser (supplied with the WWW library) are also running, using IIOP as their native protocol.

We plan to release the code into the public domain in December 1995.

A CORBA wrapper for web objects describes some of our earlier work on integrating existing systems into WWW. We use CORBA IDL to describe CGI gateways. A stub compiler is able to generate most of the code for the CGI gateway and also a template HTML form to drive the gateway. The prototype code is already available.

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The benefits

Some of the benefits of using distributed objects are:

• Ease of programming: the underlying object model, the Interface Definition Language (IDL), and the supporting tools combine to simplify the task of writing distributed applications.
• Extensibility and manageability: systems built from interacting objects are inherently extensible since objects can be easily added or replaced. Extensibility allows customised management interfaces to be added to the system.
• Encapsulation and systems integration: distributed object technology has proved very effective in encapsulating "legacy systems" as objects. These objects offer interfaces that can then be used to implement an integrated system.

Converted from text 30 Nov 1995 by <rtor@ansa.co.uk>