The x3270 scripting facilities allow the interactive 3270 emulators
x3270 and c3270 to be operated under the control of another
program, and form the basis for the script-only emulator s3270.
There are two basic scripting methods.
The first is the peer script facility, invoked by the x3270-script switch, and the default mode for s3270.
This runs x3270 or s3270 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).
Inthis mode, the emulator process looks for commands on its standard input,
and places the responses on standard output and standard error output.
The second method is the child script
facility, invoked by the Script action in x3270, c3270,
or s3270.
This runs a script as a child process of the emulator.
The child has access to pipes connected to the emulator; the emulator
look 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; the file descriptor
of the pipe for responses from the emulator is passed in the environment
variable X3270OUTPUT.)
It is possible to mix the two methods.
A script can invoke another script with the Script action, and
may also be implicitly nested when a script invokes the
Connect
action, and the
ibm_hosts
file specifies a login script for that host name.
Commands are emulator actions; the syntax is the same as for the
right-hand side of an Xt translation table entry (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 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 11 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 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.
DIFFERENCES
When an action is initiated by a script, the emulators
behave in several different ways:
If an error occurs in processing an ection, the usual pop-up window does not
appear.
Instead, the text is written to standard error 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.)
The
Clear,
Enter,
PF,
and
PA
actions 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 completing.
Similarly, 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.
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, 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.
If three parameters are given,
length
characters are output, starting at the specified 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.
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
param
given 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 hexadecimal
EBCDIC
code, preceded by
0x.
EbcdicField
The same function as
AsciiField
above, except that it generates hexadecimal
EBCDIC
codes.
Info(message)
Pops up an informational message.
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 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.
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(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 forever.
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.
The optional timeout parameter specifies a number of seconds to wait
before failing the Wait action. The default is to wait forever.
For backwards compatibility,
Wait(3270)
is equivalent to
Wait(3270Mode)
Wait([timeout,] Disconnect)
Pauses the script until the host disconnects.
Often used to after sending a
logoff
command to a VM/CMS host, to ensure that the session is not unintentionally
set to
disconnected
state.
The optional timeout parameter specifies a number of seconds to wait
before failing the Wait action. The default is to wait forever.
Wait([timeout,] InputField)
A useful utility for use at the beginning of scripts and after the
Connect action.
In 3270 mode, waits until the screen is formatted, and the host has positioned
the cursor on a modifiable field.
In NVT mode, waits until the host sends at least one byte of data.
The optional timeout parameter specifies a number of seconds to wait
before failing the Wait action. The default is to wait forever.
For backwards compatibility,
Wait
is equivalent to
Wait(InputField).
Wait([timeout,] NVTMode)
Used when communicating with a host that switches between 3270 mode and
NVT mode.
Pauses the script or macro until the host negotiates NVT
mode, then waits for
a byte from the host as above.
The optional timeout parameter specifies a number of seconds to wait
before failing the Wait action. The default is to wait forever.
For backwards compatibility,
Wait(ansi)
is equivalent to
Wait(NVTMode).
Wait([timeout,] Output)
Pauses the script until the host sends further output.
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
Ascii
or
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 Wait action. The default is to wait forever.
FILE TRANSFER
The XX_LA()Transfer action implements IND$FILE file transfer.
This action requires that the IND$FILE
program be installed on the IBM host, and that the 3270 cursor
be located in a field that will accept a TSO or VM/CMS command.
Because of the complexity and number of options for file transfer, the
parameters to the XX_LA()Transfer action take the unique form
of option=value, and can appear in any order.
The options are:
Option
Required?
Default
Other Values
Direction
No
send
receive
HostFile
Yes
LocalFile
Yes
Host
No
tso
vm
Mode
No
ascii
binary
Cr
No
remove
add, keep
Exist
No
keep
replace, append
Recfm
No
fixed, variable, undefined
Lrecl
No
Blksize
No
Allocation
No
tracks, cylinders, avblock
PrimarySpace
No
SecondarySpace
No
The option details are as follows.
Direction
send (the default) to send a file to the host,
receive to receive a file from the host.
HostFile
The name of the file on the host.
LocalFile
The name of the file on the local workstation.
Host
The type of host (which dictates the form of the IND$FILE command):
tso (the default) or vm.
Mode
Use ascii (the default) for a text file, which will be translated
between EBCDIC and ASCII as necessary.
Use binary for non-text files.
Cr
Controls how Newline characters are handled when transferring
Mode=ascii files.
remove (the default) strips Newline characters in local files
before transferring them to the host.
add adds Newline characters to each host file record before
transferring it to the local workstation.
keep preserves Newline characters when transferring a local file
to the host.
Exist
Controls what happens when the destination file already exists.
keep (the default) preserves the file, causing the
XX_LA()Transfer action to fail.
replace overwrites the destination file with the source file.
append appends the source file to the destination file.
Recfm
Controls the record format of files created on the host.
fixed creates a file with fixed-length records.
variable creates a file with variable-length records.
undefined creates a file with undefined-length records (TSO hosts only).
The Lrecl option controls the record length or maximum record length for
Recfm=fixed and Recfm=variable files, respectively.
Lrecl
Specifies the record length (or maximum record length) for files created on
the host.
Blksize
Specifies the block size for files created on the host. (TSO hosts only.)
Allocation
Specifies the units for the TSO host PrimarySpace and
SecondarySpace options: tracks, cylinders or
avblock.
PrimarySpace
Primary allocation for a file created on a TSO host.
The units are given by the Allocation option.
SecondarySpace
Secondary allocation for a file created on a TSO host.
The units are given by the Allocation option.
