Re: Socket Server Application Approach

I created a similar job sometime ago, but based it on the examples in "Who Knew You Could Do That with RPG IV?
A Sorcerer's Guide to System Access and More" and do not Scott Klement's tutorial.

For what it's worth this is my tuppence-worth ...
I would expect the read to take in all of the data-string in one attempt, otherwise it would return a failure.
I keep the socket-listening job running cxontinuously.
Use of the back button by the user on the client would interact with the same instance, but we never tested for this.


Regards,
John McKay mba
www.rpglanguage.com


----- Original Message ----- From: <GKern@xxxxxxxxxxxxxxxx>
To: <rpg400-l@xxxxxxxxxxxx>
Sent: Wednesday, March 11, 2009 3:25 PM
Subject: Socket Server Application Approach

I've finally made it to the end of Scott Klement's Socket tutorial (well
not quite, there's the UDP stuff at the very end).

I have a request to develop the back end code that will accept patient
payments over the internet. The web application is written in ASP.net and
it will connect (using https) to an ILE RPG socket server. The web
application will be sending a pipe delimited string of data.

Since the web application could accept multiple payment requests
simultaneously, I have a few questions:

Would a socket spawning approach be a good fit for this application? After
(re)reading the tutorial I came to the conclusion that it would be, based
on the comment that should one job crash other jobs wouldn't be affected
(as could be the case using the select() approach).

And since this application would be accepting input over the internet via
server instances, I'm wondering if the RdLine/WrLine (as shown in the
tutorial) is acceptable (as opposed to using GetLine & PutLine) from the
select() approach? Does it matter? I'm concerned that with either approach
I may still need to be concerned that the entire string of data (probably
not more than 2048 bytes) may not be received with one read - which leads
to my next question:

Should the RdLine/GetLine occur in a loop to ensure the full contents of
the string are received? Or does specifying the (maximum) length of RdLine
always return (up to) that number of bytes?

And finally, since the example SVREX7I does not use a "dow 1=1", I'm
coding my logic as follows:

1) Website connects to server instance, and passes data string to server
instance;
2) Server instance reads data via RdLine, does edits and returns result
string to website via WrLine;
3) Server instance ends.

At this point should the server instance job be allowed to end?

If for example, the results returned to the website indicate that the data
string was incomplete or contained errors, should a subsequent retry (by
the user) occur and interact with the server instance that did the initial
edit?

Or should I allow a new server instance to take control?

My guess is that I would want a new server instance each time since I have
no guarantee that the user on the internet will, with certainty, continue
the transaction to completion.

This is the direction I'm moving in. Comments welcome.

Thanks!

Regards, Jerry

Gerald Kern - MIS Project Leader
Lotus Notes/Domino Administrator
IBM Certified RPG IV Developer
The Toledo Clinic, Inc.
4235 Secor Road
Toledo, OH 43623-4299
Phone 419-479-5535
gkern@xxxxxxxxxxxxxxxx


This e-mail message, including any attachments, is for the sole use of the
intended recipient(s) and may contain confidential and privileged
information. Any unauthorized use, disclosure or distribution is
prohibited. If you are not the intended recipient, please inform the
sender by reply e-mail and destroy this and all copies of this message.
--
This is the RPG programming on the IBM i / System i (RPG400-L) mailing list
To post a message email: RPG400-L@xxxxxxxxxxxx
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/rpg400-l
or email: RPG400-L-request@xxxxxxxxxxxx
Before posting, please take a moment to review the archives
at http://archive.midrange.com/rpg400-l.