Ubuntu Manpage: Scripting Facilities for x3270, c3270 and s3270

NAME

       Scripting Facilities for x3270, c3270 and s3270

SYNOPSIS

       x3270 -script [ x3270-options ]
       x3270 -socket [ x3270-options ]
       x3270 -scriptport port [ x3270-options ]
       c3270 -socket [ c3270-options ]
       c3270 -scriptport port [ s3270-options ]
       s3270 [ s3270-options ]
       Script ( command [ ,arg... ] )

DESCRIPTION

The x3270 scripting facilities allow the interactive 3270 emulators x3270 and c3270 to be
operated under the control of another program, and forms the basis for the script-only
emulator s3270.

There are four basic scripting methods. The first is the peer script facility, invoked by
the x3270 -script switch, and the default mode for s3270. This runs the emulator as a
child of another process. Typically this would be a script using expect(1), perl(1), or
the co-process facility of the Korn Shell ksh(1). In this mode, the emulator process
looks for commands on its standard input, and places the responses on standard output.

The second method is the child script facility, invoked by the emulator's Script action.
This runs a script as a child process of the emulator. The child has access to pipes
connected to the emulator; the emulator looks for commands on one pipe, and places the
responses on the other. The file descriptor of the pipe for commands to the emulator is
passed in the environment variable X3270INPUT (e.g., the text string "7" if the file
descriptor is 7); the file descriptor of the pipe for responses from the emulator is
passed in the environment variable X3270OUTPUT.

The third method uses a TCP socket. The -scrpiptport command-line option causes the
emulator to bind a socket to the specified port (on the IPv4 loopback address, 127.0.0.1).
The emulator accepts TCP connections on that port. Multiple commands and responses can be
sent over each connection.

The fourth method uses a Unix-domain socket. The -socket command-line option causes the
emulator to create a Unix-domain stream socket named /tmp/x3sck.pid. The emulator accepts
connections to that socket. Multiple commands and responses can be sent over each
connection.

It is possible to nest the methods. For example, a peer or TCP socket script can invoke
the Script action. The calling script will be resumed when the nested script completes.

Commands are emulator actions; the syntax is the same as for the right-hand side of an
x3270 or c3270 keymap. Unlike translation tables, action names are case-insensitive, can
be uniquely abbreviated, and the parentheses may be omitted if there are no parameters.
Any input line that begins with # or ! is treaded as a comment and will be ignored.

Any emulator action may be specified. Several specific actions have been defined for use
by scripts, and the behavior of certain other actions (and of the emulators in general) is
different when an action is initiated by a script.

Some actions generate output; some may delay completion until the certain external events
occur, such as the host unlocking the keyboard. The completion of every command is marked
by a two-line message. The first line is the current status of the emulator, documented
below. If the command is successful, the second line is the string "ok"; otherwise it is
the string "error".

STATUS FORMAT

The status message consists of 12 blank-separated fields:

1 Keyboard State
If the keyboard is unlocked, the letter U. If the keyboard is locked waiting for a
response from the host, or if not connected to a host, the letter L. If the
keyboard is locked because of an operator error (field overflow, protected field,
etc.), the letter E.

2 Screen Formatting
If the screen is formatted, the letter F. If unformatted or in NVT mode, the
letter U.

3 Field Protection
If the field containing the cursor is protected, the letter P. If unprotected or
unformatted, the letter U.

4 Connection State
If connected to a host, the string C(hostname). Otherwise, the letter N.

5 Emulator Mode
If connected in 3270 mode, the letter I. If connected in NVT line mode, the letter
L. If connected in NVT character mode, the letter C. If connected in unnegotiated
mode (no BIND active from the host), the letter P. If not connected, the letter N.

6 Model Number (2-5)

7 Number of Rows
The current number of rows defined on the screen. The host can request that the
emulator use a 24x80 screen, so this number may be smaller than the maximum number
of rows possible with the current model.

8 Number of Columns
The current number of columns defined on the screen, subject to the same difference
for rows, above.

9 Cursor Row
The current cursor row (zero-origin).

10 Cursor Column
The current cursor column (zero-origin).

11 Window ID
The X window identifier for the main x3270 window, in hexadecimal preceded by 0x.
For s3270 and c3270, this is zero.

12 Command Execution Time
The time that it took for the host to respond to the previous commnd, in seconds
with milliseconds after the decimal. If the previous command did not require a
host response, this is a dash.

DIFFERENCES

       When an action is initiated by a script, the emulators behave in several different ways:

       If an error occurs in processing an action, the  usual  pop-up  window  does  not  appear.
       Instead, the text is written to standard output.

       If  end-of-file  is  detected  on  standard input, the emulator exits.  (A script can exit
       without killing the emulator by using the CloseScript  action,  below.)   Note  that  this
       applies  to  peer scripts only; end-of-file on the pipe connected to a child script simply
       causes the pipes to be closed and the Script action to complete.

       The Quit action always causes the emulator to exit.  (When called from  the  keyboard,  it
       will exit only if not connected to a host.)

       Normally,  the  AID  actions  (Clear,  Enter, PF, and PA) will not complete until the host
       unlocks the keyboard.  If the parameter to a String action includes a code for  one  these
       actions, it will also wait for the keyboard to unlock before proceeding.

       The AidWait toggle controls with behavior.  When this toggle is set (the default), actions
       block as described above.  When the toggle is clear,  AID  actions  complete  immediately.
       The  Wait(Output)  action  can  then  be  used  to  delay  a script until the host changes
       something on the screen, and the Wait(Unlock) action can be used to delay a  script  until
       the host unlocks the keyboard, regardless of the state of the AidWait toggle.

       Note that the Script action does not complete until end-of-file is detected on the pipe or
       the CloseScript action is called by the child process.  This behavior is not  affected  by
       the state of the AidWait toggle.

BASIC PROGRAMMING STRATEGIES

3270 session scripting can be more difficult than other kinds of scripting, because it can
be hard to tell when the host is finished processing a command. There is a well-defined
3270 Data Stream facility for doing this: The emulator locks the keyboard when it sends
the host an AID, and the later host unlocks the keyboard. The emulator supports this
facility directly by not allowing an AID action to complete until the keyboard is
unlocked. Unfortunately, some hosts and some host applications unlock the keyboard as
soon as they begin processing the command, instead of after it is finished. A human
operator can see on the screen when the command is finished (e.g., when a READY prompt is
displayed), but it can be difficult for a script to do this. For such early-unlock hosts,
the only option in a script is to poll the screen until it can determine that the command
is complete.

Another complication is that host I/O and script operation are asynchronous. That is, the
host can update the screen at any time, even between actions that are reading the screen
contents, so a script can get inconsistent results. Assistance for this problem is
provided by the Snap action. The Snap(Save) action saves a snapshot of the screen in a
special buffer. Then the script can use Snap variants of the Ascii and Ebcdic actions
(Snap(Ascii) and Snap(Ebcdic)) to query the saved buffer -- which the host cannot modify
-- to get the data it wants. Finally, Snap(Wait Output) blocks the script until the host
modifies the screen, specifically since the last call to Snap(Save). Thus a script can
poll the screen efficiently by writing a loop that begins with Snap(Save) and ends with
Snap(Wait Output).

SCRIPT-SPECIFIC ACTIONS

The following actions have been defined or modified for use with scripts. (Note that
unlike the display on the status line, row and col coordinates used in these actions use
[0,0] as their origin at the upper left, not [1,1]).

AnsiText
Outputs whatever data that has been output by the host in NVT mode since the last
time that AnsiText was called. The data is preceded by the string "data: ", and
has had all control characters expanded into C backslash sequences.

This is a convenient way to capture NVT mode output in a synchronous manner without
trying to decode the screen contents.

Ascii(row,col,rows,cols)

Ascii(row,col,length)

Ascii(length)

Ascii Outputs an ASCII text representation of the screen contents. Each line is preceded
by the string "data: ", and there are no control characters.

If four parameters are given, a rectangular region of the screen is output. (Note
that the row and column are zero-origin.)

If three parameters are given, length characters are output, starting at the
specified zero-origin row and column.

If only the length parameter is given, that many characters are output, starting at
the cursor position.

If no parameters are given, the entire screen is output.

The EBCDIC-to-ASCII translation and output character set depend on the both the
emulator character set (the -charset option) and the locale. UTF-8 and certain
DBCS locales may result in multi-byte expansions of EBCDIC characters that
translate to ASCII codes greater than 0x7f.

AsciiField
Outputs an ASCII text representation of the field containing the cursor. The text
is preceded by the string "data: ".

Connect(hostname)
Connects to a host. The command does not return until the emulator is successfully
connected in the proper mode, or the connection fails.

CloseScript(status)
Causes the emulator to stop reading commands from the script. This is useful to
allow a peer script to exit, with the emulator proceeding interactively. (Without
this command, the emulator would exit when it detected end-of-file on standard
input.) If the script was invoked by the Script action, the optional status is
used as the return status of Script; if nonzero, Script will complete with an
error, and if this script was invoked as part of login through the ibm_hosts file,
the connection will be broken.

ContinueScript([param])
Allows a script that is waiting in a PauseScript action, below, to continue. The
optional param string is output by the PauseScript action.

Disconnect
Disconnects from the host.

Ebcdic(row,col,rows,cols)

Ebcdic(row,col,length)

Ebcdic(length)

Ebcdic The same function as Ascii above, except that rather than generating ASCII text,
each character is output as a 2-digit or 4-digit hexadecimal EBCDIC code.

EbcdicField
The same function as AsciiField above, except that it generates hexadecimal EBCDIC
codes.

Info(message)
In x3270, pops up an informational message. In c3270 and wc3270, writes an
informational message to the OIA (the line below the display). Not defined for
s3270 or tcl3270.

Expect(text[,timeout])
Pauses the script until the specified text appears in the data stream from the
host, or the specified timeout (in seconds) expires. If no timeout is specified,
the default is 30 seconds. Text can contain standard C-language escape (backslash)
sequences. No wild-card characters or pattern anchor characters are understood.
Expect is valid only in NVT mode.

MoveCursor(row,col)
Moves the cursor to the specified zero-origin coordinates.

PauseScript
Stops a script until the ContinueScript action, above, is executed. This allows a
script to wait for user input and continue. Outputs the single parameter to
ContinueScript, if one is given.

PrintText([command,]filter)
Pipes an ASCII representation of the current screen image through the named filter,
e.g., lpr.

PrintText([html,][append,][replace,]file,filename)
Saves the current screen contents in a file. With the html option, saves it as
HTML, otherwise saves it as plain ASCII. The append option (the default) causes
the data to be appended to the file if it already exists. The replace option causes
the file to be overwritten instead.

PrintText(html,string)
Returns the current screen contents as HTML.

Query(keyword)
Returns state information. Keywords are:

Keyword Output
───────────────────────────────────────────────────
BindPluName BIND PLU returned by the host
ConnectionState TN3270/TN3270E mode and submode
CodePage Host code page
Cursor Cursor position (row col)
Formatted 3270 format state (formatted or
unformatted)
Host Host name and port
LocalEncoding Local character encoding
LuName Host name LU name
Model 3270 model name (IBM-327x-n)
ScreenCurSize Current screen size (rows cols)
ScreenMaxSize Maximum screen size (rows cols)
Ssl SSL state (secure or not-secure)
and host validation state (host-
verified or host-unverified)

Without a keyword, Query returns each of the defined attributes, one per line,
labeled by its name.

ReadBuffer(Ascii)
Dumps the contents of the screen buffer, one line at a time. Positions inside data
fields are generally output as 2-digit hexadecimal codes in the current display
character set. If the current locale specifies UTF-8 (or certain DBCS character
sets), some positions may be output as multi-byte strings (4-, 6- or 8-digit
codes). DBCS characters take two positions in the screen buffer; the first
location is output as a multi-byte string in the current locale codeset, and the
second location is output as a dash. Start-of-field characters (each of which
takes up a display position) are output as SF(aa=nn[,...]), where aa is a field
attribute type and nn is its value.

Attribute Values
─────────────────────────────────────
c0 basic 3270 20 protected
10 numeric
04 detectable
08 intensified
0c non-display
01 modified
41 highlighting f1 blink
f2 reverse
f4 underscore
f8 intensify
42 foreground f0 neutral black
f1 blue
f2 red
f3 pink
f4 green
f5 turquoise
f6 yellow
f7 neutral white
f8 black
f9 deep blue
fa orange
fb purple
fc pale green
fd pale turquoise
fe grey

ff white
43 character set f0 default
f1 APL
f8 DBCS

Extended attributes (which do not take up display positions) are output as
SA(aa=nn), with aa and nn having the same definitions as above (though the basic
3270 attribute will never appear as an extended attribute).

In addition, NULL characters in the screen buffer are reported as ASCII character
00 instead of 20, even though they should be displayed as blanks.

ReadBuffer(Ebcdic)
Equivalent to ReadBuffer(Ascii), but with the data fields output as hexadecimal
EBCDIC codes instead. Additionally, if a buffer position has the Graphic Escape
attribute, it is displayed as GE(xx).

Script(path[,arg...])
Runs a child script, passing it optional command-line arguments. path must specify
an executable (binary) program: the emulator will create a new process and execute
it. If you simply want the emulator to read commands from a file, use the Source
action.

Snap Equivalent to Snap(Save) (see below).

Snap(Ascii,...)
Performs the Ascii action on the saved screen image.

Snap(Cols)
Returns the number of columns in the saved screen image.

Snap(Ebcdic,...)
Performs the Ebcdic action on the saved screen image.

Snap(ReadBuffer)
Performs the ReadBuffer action on the saved screen image.

Snap(Rows)
Returns the number of rows in the saved screen image.

Snap(Save)
Saves a copy of the screen image and status in a temporary buffer. This copy can
be queried with other Snap actions to allow a script to examine a consistent screen
image, even when the host may be changing the image (or even the screen dimensions)
dynamically.

Snap(Status)
Returns the status line from when the screen was last saved.

Snap(Wait[,timeout],Output)
Pauses the script until the host sends further output, then updates the snap buffer
with the new screen contents. Used when the host unlocks the keyboard (allowing
the script to proceed after an Enter, PF or PA action), but has not finished
updating the screen. This action is usually invoked in a loop that uses the
Snap(Ascii) or Snap(Ebcdic) action to scan the screen for some pattern that
indicates that the host has fully processed the last command.

The optional timeout parameter specifies a number of seconds to wait before failing
the Snap action. The default is to wait indefinitely.

Source(file)
Read and execute commands from file. Any output from those commands will become
the output from Source. If any of the commands fails, the Source command will not
abort; it will continue reading commands until EOF.

Title(text)
Changes the x3270 window title to text.

Transfer(keyword=value,...)
Invokes IND$FILE file transfer. See FILE TRANSFER below.

Wait([timeout,] 3270Mode)
Used when communicating with a host that switches between NVT mode and 3270 mode.
Pauses the script or macro until the host negotiates 3270 mode, then waits for a
formatted screen as above.