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May 31, 2002
PLEASE READ OUR ARTICLES ON CREATING SCREEN SCRAPERS FOR ACTIVEX
AND DELPHI/C++BUILDER
How do I create screen scraper applications?
How can I send text and controls to the emulator?
How can I access the fields of the screen rather
than just the text?
How do I know when a screen is complete?
What's the difference between OnEOR and OnEOS?
How does SSL work?
What is the pricing for Visual 3270?
How do I create screen scraper applications?
Using Visual 3270 provides you with a rich set of functions and
methods to "extract" data from your existing host sessions
and place them on a web server such as IIS or in other types of
applications. You should read our two articles on creating screen
scrapers using Visual 3270 to gain excellent insight on our product
and how it can "rejuventate" your host applications:
Visual
3270 Screen Scraping for Delphi
Visual
3270 Screen Scraping for ActiveX
How can I send text and controls to
the emulator?
Make sure you have read our articles on creating screen scrapers.
You can easily send text by using the KeyPress() function and
send commands such as F1, Enter, F2, etc by using using the KeyDown()
function passing in the Virtual Key Code or ascii value of the
Attention Identifier (AID) requested. Check with your programming
environment's KeyPress and KeyDown methods/events for more information.
How can I access the fields of the screen
rather than just the text?
If you are creating a complex application then Visual 3270 can
provide you with complete control and access to the "raw"
data from the host device. First, there are two buffers you can
use: screen_buf[] which provides you with the screen data in CG
format (you may translate this buffer using cg2asc[] array), and
inbuf[] which provides you with the raw "ebcdic" data.
It is advised that you do not use the inbuf[] array as this array
is the data stream that builds the screen_buf[] array which represents
a continuous character buffer from 0 to 1919 (rows * cols-1).
For example, lets say you wanted to know the number of fields,
either protected or unprotected on your screen. Just iterate through
the scren_buf[] array passing in each character to the IS_FA()
function. This will return true or false depending on the character
passed in. DO NOT CONVERT the screen_buf[] character passed in
to ASCII, leave it as CG.
If for example you wish to know whether a field is protected
or unprotected it is first best to check whether or not it is
an FA (Field Attribute) and use the FA_IS_PROTECTED() function,
where return value of false indicates an unprotected field. You
may also use GetAttributes() and GetCharAttributes() to determine
the color of a character as well.
How do I know when a screen is complete?
The OnEOS (On End of Screen) event is fired when the host system
has sent an unlock keyboard command and the data stream is larger
than 8 characters (minimum length for a screen). Developers should
note that the OnEOS is fired under command of the mainframe and
it is common, though not normal, for the mainframe to send another
screen immediately after sending an existing screen. Developers
should check either the fields in the data stream at a known location
or the characters on the screen unless you are sure that the screen
is in fact complete. The best practice is to test using a Visual
emulator looking for OnEOS events to determine if your mainframe
follows normal operations.
What's the difference between OnEOR and
OnEOS?
OnEOR (On End of Record) is a stopping point in a screen and is
usually concurrent with OnEOS; however, OnEOR's do not indicate
a completed screen, it just merely indicates to the emulator that
its time to start a new screen build which can happen several
times per screen. An OnEOS occurs only when the mainframe has
explicitly told the emulator to release the keyboard and allow
the user to type which signifies an end of screen. OnEOS's differ
from OnKeyboardRestore in that OnEOS only fires when more than
8 characters have arrived to build the screen.
How does SSL work?
SSL client emulators can only connect to SSL enabled host systems.
Turn this on in the emulator only if your administrator has explicitly
detailed how to connect to your server. For more information on
SSL please visit our VisualSSL
website which goes into excrutiatingly detailed discussion on
SSL and Public Key Infrastructure.
What is the pricing for Visual 3270?
Call us today for pricing. We are exceptionally well priced for
all application types. 407-833-9776 extension 1. Though each customer
is unique we do have preliminary pricing for your review:
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