Re: Turning green-screen apps into web apps

[Pete Helgren <pete@xxxxxxxxxx>]

Mike,

Personally, I haven't seen anything that can reverse engineer the 
existing 5250 code in a way that is truly useful when rendered as HTML.  
I wish there was, but even with source code I haven't yet seen a tool 
that transforms the 5250 screen into something completely usable that 
requires no additional tweaking.

If I had a shop that was very comfortable with HTML, CSS, and 
jQuery/JavaScript and was an RPG shop, I'd start from scratch and 
redesign the user interface using your client side tools (the 
aforementioned HTML, CSS, and jQuery/JavaScript) and use Ajax/JSON as 
the data delivery/update method. You might be able to leverage any RPG 
you have but even if you rewrote your DB  I/O routines in RPG I bet you 
would be money ahead in the long run.

It is difficult to predict where the technology overall is going but I'd 
bet that front end and back ends will evolve differently so decoupling 
the two is essential.  The great part about that approach, and one I 
discovered after the fact, was that the programs that deliver the 
JSON/Ajax data are highly reusable in many different ways.  I have two 
completely different front end technologies I use but only one back end 
servlet that handles the DB I/O.  When it was time to write mobile apps, 
I already had my back end stuff written so I could concentrate on the 
front end details.  I simply invoke a URL and it delivers JSON to the 
client.  The client updates the data the same way, through an Ajax call.

Perhaps the technologies/tools that transform 5250 to HTML use the same 
techniques, I don't know.  But my experience has been that incrementally 
delivering new apps built from the ground up will be more pleasing and 
functional to the end user and have greater flexibility than something 
reverse engineered from tool.

I originally wrote my substitute dispatch and time management/payroll 
software in RPG.  My first GUI was in ASP (ugly...too horrible to 
recall) and now it is all Java servlets (ONLY because I have four 
different DB's to support, 3 of which only run on Windows).  But, I 
still have users that run BOTH the java servlets AND the good ol 5250 
RPG stuff, side by side.  So your goal is achievable, you just have to 
choose the option that will maximize your client options and leverage 
the skills of your shop.

YMMV of course.

Pete Helgren
Value Added Software, Inc
www.asaap.com
www.opensource4i.com


On 1/3/2011 2:13 PM, Mike Wills wrote:
> We are starting to look more seriously at making some of our green-screen
> apps into intranet apps. The first program would from our payroll software
> that is vendor created and supported. Since we don't control the source (in
> this case), we cannot take an approach like RPGUI and we would also like to
> allow for green-screen usage AND web usage at the same time. I have been
> looking at software like Presto from BCD and NewLook from Look Software that
> essentially does screen-scraping. I have not tried either one yet.
>
> As I have said on here before, our knowledge base here is RPG and C# and we
> would like to avoid PHP if possible so we don't spread out our knowledge
> base too thin. We also have a solid base of HTML, CSS, and
> jQuery/JavaScript.
>
> 1. Do you use this type of software and how do you like it?
> 2. Which product do you use/like/wish you used instead?
> 3. How easily customizable is it and do you do any?
> 4. Could I have an ASP.NET application work with the framework to create a
> custom application to interface with a green-screen application?
>
> Also, has anyone done a comparison of each of the options head-to-head to
> see where the pluses and minuses are?
>
> I'm sure I'll have more questions, but this is a start. I am just trying to
> wrap my head around this better to put together a good proposal.
>
> --
> Mike Wills
> http://mikewills.me