Scripting Facilities for x3270

SYNOPSIS

Script(command[,arg...])

DESCRIPTION

There are two basic methods. The first is the peer script facility, invoked by the -script switch. This runs x3270 as a child of another process. Typically this would be a script using expect(1) or the co-process facility of the Korn Shell ksh(1). When the -script switch is given, x3270 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. This runs a script as a child process of x3270. The child has access to pipes connected to x3270; x3270 looks for commands on one pipe, and places the responses on the other. (The file descriptor of the pipe for commands to x3270 is passed in the environment variable X3270INPUT; the file descriptor of the pipe for responses from x3270 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. Scripts 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 X actions; the syntax is the same as for the right-hand side of an X translation table (an x3270 keymap), with two exceptions: only one action may appear per line, and if no parameters are needed by the action, the parentheses may be omitted.

Any x3270 action may be specified. Several new actions have been defined for use by scripts, and the behavior of certain other actions (and of x3270 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 x3270, documented below. If the command is successful, the second line is the string "ok"; otherwise it is the string "error".

STATUS FORMAT

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.

Screen Formatting

If the screen is formatted, the letter F. If unformatted or in ANSI mode, the letter U.

Field Protection

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

Connection State

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

Emulator Mode

If connected in 3270 mode, the letter I. If connected in ANSI line mode, the letter L. If connected in ANSI character mode, the letter C. If not connected, the letter N.

Model Number (2-5)

Number of Rows

The current number of rows defined on the screen. The host can request that x3270 use a 24x80 screen, so this number may be smaller than the maximum number of rows possible with the current model.

Number of Columns

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

Cursor Row

The current cursor row (zero-origin).

Cursor Column

The current cursor column (zero-origin).

Window ID

The X window identifier for the main x3270 window, in hexadecimal preceded by 0x.

DIFFERENCES

If an error occurs, 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, x3270 exits. (A script can exit without killing x3270 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 x3270 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.

NEW ACTIONS

AnsiText()

Outputs whatever data that has been output by the host in ANSI 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 ANSI mode output in a synchronous manner without trying to decode the screen contents.

Ascii(row, col, rows, cols)
Ascii(row, col, len)
Ascii(len)
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 all four parameters are given, a rectangular region of the screen is output.

If three parameters are given, len characters are output, starting at the specified row and column.

If only the len 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 action does not return until x3270 is successfully connected in the proper mode, or the connection fails.

CloseScript(status)

Causes x3270 to stop reading commands from the script. This is useful to allow a peer script to exit, with x3270 proceeding interactively. (Without this action, x3270 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, len)
Ebcdic(len)
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.

Expect(text)
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 ANSI mode.

Info(message)

Pops up an informational message.

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().

Wait()

A useful utility for use at the beginning of scripts and after the Connect() action. Waits until the screen is formatted, and the host has positioned the cursor on a modifiable field.

SEE ALSO