Legacy integration with screen scrapers

[Nick Harrison]

Anybody out there have any strong feelings for or against the use of HACL
to provide a web front end to some legacy systems. If anybody can point
me in the direction of case studies for this sort of thing I would
appreciate it. The host access class libraries that allow you to interact
with the 5250 data stream from the screen can be wrapped in COM objects
that can subsequently be used from a web page. Im not sure about basing
legacy/web access on what is essentially a screen scraper.

Thoughts?

[Nathan M. Andelin]

> If anybody can point me in the direction of case studies for this
> sort of thing I would appreciate it.

The April 2001, and April 2002 magazine issues at
www.iseriesnetwork.com features a number of GUI emulation products.
Maybe one of the featured products used the HACL API's under the
covers.

> Im not sure about basing legacy/web access on what is
> essentially a screen scraper.

On the positive side, it offers a connection to an interactive
application without changing it.

On the other hand, screen scrapers have a reputation for poor
performance. And IBM's pricing of the 5250 interface is very high in
comparison to a strait HTTP connection. And it requires that a Wintel
server and application be added to the network. In my opinion, the
negatives far outweigh the positive.

As an alternative, I've been doing some R&D on a workstation interface
that requires a small modification to the interactive application.
But the interface provides ILE exit points and an API to communicate
with OS/400 Workstation Management as well as the HTTP Server. It
enables an interactive program to generate 5250, or HTML, or XML, or
WML with little modification.

The following screen shots show a sample RPG program that I converted
to use the other workstation interface:

http://www.relational-data.com/rdweb/rd1200s/green.html

Nathan M. Andelin
www.relational-data.com