Re: Driving TN5250 non-interactively

It seems like what you want to know are details about the 5250 data stream.

5250 is a data stream that contains not only plain text data, but attributes
for the data displayed on the screen (like foreground color, background
color, underlining and bold), along with keyboard command attention (CA) and
command function (CF) keys.

I think the best source of that complete information is specified in a set
of books by IBM, like "SNA Formats", and others related to the SNA data
streams used in 5250-like terminals.

There is an on-line source of information where you will probably find it.

I'd suggest you search the IBM search engine at this URL.  You will have to
look for further to find what you need.  Try to find out one version that
deals with iSeries under the same bookmanager library reader.

http://www-03.ibm.com/systems/z/os/zos/library/softcopy/softfeat.html

Good luck!

X Sanchez

-----Mensaje original-----
De: linux5250-bounces-Zwy7GipZuJhWk0Htik3J/[email protected] [mailto:linux5250-bounces-Zwy7GipZuJhWk0Htik3J/[email protected]]
En nombre de Richard Nolde
Enviado el: Jueves, 15 de Julio de 2010 04:47 p.m.
Para: linux5250-Zwy7GipZuJhWk0Htik3J/[email protected]
Asunto: [LINUX5250] Driving TN5250 non-interactively

TN5250 list members:

I've been tasked with writing an interface between an application that 
runs on a remote iSeries host, accessible with TN5250 over a private 
network, and our application that would query the iSeries in real time 
without human interaction. My application will run on a Linux or AIX 
box, and act like a broker between the local application and the remote 
iSeries host application that contains the database we are querying.

I've been studying the current TN5250 source code to get a feel for what 
I'm up against and clearly this is no simple task. Can anyone recommend 
one or more books/online sources about how the TN5250 interface on 
iSeries works. eg format fields, data types, etc. I can generate the 
requests manually with TN5250 and get the desired results back as a 
spool file with lp5250d, so my main objective is how to replace the 
curses interface with one that reads from a file or other 
non-interactive source. Eventually, I will provide a daemon that handles 
requests from multiple clients over a socket interface and serializes 
them for submission to the iSeries host, but that isn't necessary for now.

 From what I've read and seen by playing with the remote application, I 
will need to know the position, length, and data types for each field of 
each screen that I wish to use, and Action or Function Key definitions 
for each screen. Assuming I can build a map that identifies each 
component of each screen, and the sequence of screens that will be 
encountered, I would then load each field with the appropriate value and 
call one of the TN5250 functions to send the data on the stream to the 
remote host application.  If the application screen produces output, I 
may or may not chose to parse it directly if I can get everything I want 
from the print spool that is returned via lp5250d.  In the sample cases 
that I have looked at, the screen output simulates bold printing by 
issuing a carriage return and then resending the data for selected 
fields a second time, as might have been done with ancient line printers 
of yore. I can probably parse this out but it would be nice to be able 
to disable this altogether.  I'm currently not using a Host Print 
Transform on the print spool output, only scs2ascii as there are no 
graphics involved. The returned data is in a format that I should be 
able to parse on my end as long as I know the parameters that were used 
to generate the query and the screen from which the output is derived.

I note that the TN5250 application can be compiled without ncurses 
support, but doing so produced an executable that will not interact with 
the remote host. I assume that this is due to the field position 
requirements of the remote application.

My initial approach is to build a profile of all the function calls in 
the tn5250 interactive application and see which ones call functions 
from the ncurses library. Once I understand how/where the screen 
co-ordinates are being set/read, I may be able to write a function that 
will read the appropriate values from my template files and the input 
data stream.

Any ideas/suggestions and online documentation references would be 
welcome.  I have no access to the iSeries host except through the remote 
application. My servers run Linux or AIX 5.3.

Thanks,
Richard Nolde
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