RE: How to keep persistant data between web apps

["Walden H. Leverich" <WaldenL@xxxxxxxxxxxxxxx>]

>My first thought was to generate a session id that would then be
written to 
>a file along with the additional info that I want to keep and then have
a 
>procedure that would retrieve the info based on the session id as the
key. 

That's the way to do it. I can't speak for pages coming from RPG -- as I
don't do it that way -- but basically you define your own meaning of the
term "session." As it's generally implemented, a session is defined by a
cookie that's set on the client. Since the browser passes back the
cookies for a site w/each request the cookie becomes your key into the
session database.

If your "applications" are held on different machines (or on different
sites on the same machine) you'll need to extend the process used to
pass the session key since cookies aren't passed between sites. But when
you're changing sites you could always pass the "cookie" as a form
field, or as part of the URL.

I've shared "sessions" between ColdFusion (JSP), ASP and ASP.NET
applications hosted on several machines, works great. And thinking about
it now, there's no reason I couldn't add an RPG web-app into the mix, it
would continue to work. 

>From a DB point of view, my session system is rather simple. It's two
tables, the first is the session header, the second the session entries.


Session table looks something like:
SessionID int
SessionKey Guid
SessionIP int
SessionCreate datetime
SessionLastAccess datetime

Session Entry table:
SessionID int (FK to Session)
SessionEntryKey varchar(50)
SessionEntryValue varchar(200)

The obvious limitation is that I can't store anything in session that's
greater than 200 bytes -- and that's ok in my case. If I needed to I
could always store a BLOB and then serialize anything into session.

As for usage, I've encapsulated all session access into get() and set()
functions. A call to either requires the SessionKey and SessionEntryKey.
Get() returns the SessionEntryValue for that key in that session, Set()
takes SessionEntryValue as a parm and sets the value in the database. A
call to either updates SessionLastAccess to be now. 

There's a background task that looks at all sessions and kills any w/a
lastaccess more than xxx minutes old (we're set to 60).

Oh, and SessionID (the int) is only used internally. The value that's
passed back and forth is the sessionkey and looks like:
F6724590-3EB6-4442-95D5-1471D04D6EB9 for example. 

Make sense?

-Walden


------------
Walden H Leverich III
President & CEO
Tech Software
(516) 627-3800 x11
WaldenL@xxxxxxxxxxxxxxx
http://www.TechSoftInc.com

Quiquid latine dictum sit altum viditur.
(Whatever is said in Latin seems profound.)
  


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Scott Swaim
Sent: Friday, 18 February, 2005 10:06
To: MIDRANGE-L@xxxxxxxxxxxx
Subject: How to keep persistant data between web apps

I am just now starting to program for the web.  I am running V5R1 (with
all 
current ptf's)  I am working through the easy400 deliverables and
modifying 
them to meet my needs.  I am trying to create a web application
framework 
that would allow our Distributors to log into the website and then have 
access to there account information.

The problem that I am facing now is try to keep data persistent between 
applications.  I know that I can create a session HANDLE that will allow
for 
persistent for one app.  I would like for the user to log in using my
own 
auth method and then keep the information (i.e. customer number, agent
code, 
etc) to be used for other apps on the site.

My first thought was to generate a session id that would then be written
to 
a file along with the additional info that I want to keep and then have
a 
procedure that would retrieve the info based on the session id as the
key.

I am new to this area for web programming.  I would like to stay with
RPG as 
my language as that is what I am most familiar.  I am familiar with PHP
but 
I do not have the PASE environment installed on my machine to run PHP
with 
my Apache server.


Thank for any input.


Scott Swaim 

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