Re: 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