Re: Thinking out loud about a new RPG web framework

["Tom Huff" <tehuff@xxxxxxxxxxxxx>]

Ahh, the joys of NEP-MRT's... Remember NEP-NOP's ?

Tom

-----Original Message-----
From: web400-bounces@xxxxxxxxxxxx [mailto:web400-bounces@xxxxxxxxxxxx] On
Behalf Of Joe Pluta
Sent: Thursday, June 05, 2008 3:15 PM
To: Web Enabling the AS400 / iSeries
Subject: Re: [WEB400] Thinking out loud about a new RPG web framework

Aaron Bartell wrote:
> Have a "mother router" program that sits under Apache and all it does is
> receives in HTTP requests from the browser and based on a hidden form
value
> (or cookie storing a session ID) it would appropriately "write" that
request
> to a keyed data queue where a program is waiting for that specific session
> key.  Upon receiving the data queue entry, the business logic program
> processes the contents of the HTTP post by evaluating the action that was
> taken (just like how green screen programming checks for the function
key).
> It then determines what to respond with and goes back into a wait state on
a
> data queue "read" (just like waiting on EXFMT).  The benefit in this case
is
> that all global variables, open data paths, and SQL cursors were able to
> remain open and stateful as it relates to that specific users
interactions.
> The data queue layer is basically acting as the replacement mechanism for
> EXFMT.
>
> The issue I had previously is that each web browsing user had their own
job
> on the iSeries which could potentially become burdensome for a public
> website with thousands of users coming in.
>   
I'm not going to go too deep into this today, but I am a little hazy on 
some specific issues.  Let's say you have 100 users doing order entry.  
They're all calling the same program.  Is there only a single instance 
of this program?  Or is there one per user?  If it's the former, then 
that program will have to restore state based on the session ID for 
every request.  This is what we had back in the days of NEP-MRT CCP, and 
it's *not* a trivial task, especially as the programs grow.

If, on the other hand, there is one job per session, then why bother 
with the mother router?  In fact, let each HTTP session have its own job 
and now we're back to my architecture.  In fact, with servlets, we just 
use the toolbox to create a connectin, and the job we use is the 
QZRCSRVS job.

There is the issue of scalability for large sites, but the majority of 
those sites can probably use a non-persistent application such as a 
catalog right up until the time when they need to actually do an order - 
which is when they need to log in and fire up the RPG program, which is 
when you would establish a support job.

Joe