[WWW4]

A Web of Distributed Objects

Owen Rees - Nigel Edwards - Mark Madsen - Mike Beasley - Ashley McClenaghan

What did we do

• The idea
  • Seamless interoperability between CORBA and WWW
    • CORBA objects made to look like WWW resources
    • WWW resources made to look like CORBA objects
  • CORBA IDL representation of HTTP
    • Methods as operations, headers as parameters
    • Many possible mappings can coexist
    • Use IIOP - Internet Inter-ORB Protocol - standardised by OMG
• The implementation
  • Gateways
    • H2I - HTTP to IIOP
    • I2H - IIOP to HTTP
  • Translate the invocations
    • Interoperability rather than just tunnelling

Why did we do it

• Make CORBA technology accessible to the web
• Make Web technology and resources accessible to CORBA
• Examples of use
  • HTTP-IIOP-HTTP tunnelling with dynamic URL translation
  • Alternative to CGI - invoke an object via ORB
  • Web browser as UI for CORBA system

The Web and CORBA Worlds Joined

What We Did: Overview

• Gateways
  • H2I: takes HTTP to IIOP, used like a proxy
  • I2H: takes IIOP to HTTP
• Locator
  • Finds IIOP paths for H2I or other client
  • H2I can fall back to HTTP
• Invocation translations
  • Not just tunnelling
  • Full interoperability

Structure of the IIOP to HTTP Gateway

Structure of the HTTP to IIOP Gateway and Locator

The Components we used

We used publicly and freely available components.

• W3 Reference Library from W3C
• SunSoft Inter-Orb Engine (via OMG)
• Stub Compiler
  • SunSoft IDL compiler front end
  • ANSA (dead hyperlink - http://www.ansa.co.uk/ANSA/) back end for IOE
• MIT pthreads

What We Can Do With It

• HTTP-IIOP-HTTP tunnelling with dynamic URL translation
• Proof of concept: Orbix from Iona (dead hyperlink - http://www.iona.ie/) in place of IOE
• Object invocation via an ORB as an alternative to CGI
• Web browser becomes uniform user interface for CORBA

Where You Can Get It

• Publicly available by anonymous FTP
• See <URL:(dead hyperlink - http://www.ansa.co.uk/ANSA/ISF/)>
  • (dead hypelink - http://www.ansa.co.uk/ANSA/) Information Services Framework Group
  • Built under the ANSAweb Project
• <(dead hyperlink - http://www.ansa.co.uk/ANSA/) sponsors already using early prototypes

What Was Learned

• Interoperability is achievable and practical
  • ANSAweb built with existing freely available technology components
• Existing technology/information investments preserved and enhanced
  • no change to existing resources
  • more existing resources become accessible
• Worth doing to leverage existing CORBA systems
  • Existing heavy investments in CORBA accessible via WWW

Who Did It and When

The ANSAweb Project was begun in June 1995. The team members who have been involved are:

• Owen Rees (ANSA)
• Nigel Edwards (HPLB)
• Mark Madsen (ANSA)
• Mike Beasley (ICL)
• Ashley McClenaghan (ANSA<
• Toby Speight (ANSA)
• Zhixue Wu (ANSA)

This presentation was produced by Owen Rees and Mark Madsen.

Converted from text 15 Jul 1996 by <tms@ansa.co.uk>