Python TN3270 library.
Inspired by pyte, this is a pure Python TN3270 library providing data stream parsing and in-memory emulation. It does not include a user interface or routines to support automation, instead it is designed to be used to build user-facing emulators and automation libraries.
pytn3270 is a work in progress and only supports basic TN3270 emulation.
Install using pip:
pip install pytn3270
Connect to a mainframe:
from tn3270 import Telnet, Emulator, AID, CharacterCell
telnet = Telnet('IBM-3279-2-E')
telnet.open('mainframe', 23)
emulator = Emulator(telnet, 24, 80)
# Wait until the keyboard is unlocked.
while emulator.keyboard_locked:
print('Waiting for keyboard to be unlocked...')
emulator.update(timeout=1)
# Convert the screen contents to a string, replacing attribute cells with '@'.
#
# Note that this is not supposed to demonstrate an efficient implementation.
screen = ''
for cell in emulator.cells:
if isinstance(cell, CharacterCell):
byte = cell.byte
if byte == 0:
screen += ' '
else:
screen += bytes([byte]).decode('ibm037')
else:
screen += '@'
# Display the screen.
for line in [screen[index:index+80] for index in range(0, len(screen), 80)]:
print(line)
If you are looking for information on the TN3270 protocol I'd recommend the following resources:
- Steve Millington's TN3270 Protocol Cheat Sheet
For information on the 3270 data stream (as used by TN3270) I'd recommend:
- IBM 3270 Data Stream Programmer's Reference (GA23-0059-4)
- IBM CICS The 3270 Family of Terminals
- Greg Price's 3270 Programming Overview
- Tommy Sprinkles' 3270 Data Stream Programming
- oec - IBM 3270 terminal controller