Advanced Usage

Macro scripting/DSL has been removed and is not supported. It will not be reintroduced.

Printer Sessions

Pure3270 provides high-level printer session support for TN3270E printer LU operations:

Synchronous Printer Sessions:

from pure3270 import PrinterSession

with PrinterSession(host="printer-host.example.com", port=23) as session:
    # Wait for print jobs
    import time
    time.sleep(5)

    # Get printed output
    output = session.get_printer_output()
    print("Printer output:", output)

    # Check printer status
    status = session.get_printer_status()
    print(f"Status: 0x{status:02x}")

Asynchronous Printer Sessions:

import asyncio
from pure3270 import AsyncPrinterSession

async def monitor_printer():
    async with AsyncPrinterSession(host="printer-host.example.com") as session:
        while True:
            await asyncio.sleep(5)
            output = await session.get_printer_output()
            if output:
                print("New print job received:", output)
                break

asyncio.run(monitor_printer())

Low-level Printer Support:

For advanced use cases, you can still access the underlying printer buffer:

session = Session()
session.connect("printer-host")
# Handle SCS data streams
printer_status = session.printer_buffer.get_status()

SNA Response Handling

Advanced SNA state tracking: .. code-block:: python

if session.sna_session_state == “NORMAL”:

# Session ready for 3270 data pass

# Note: response.is_negative() not implemented; use exception handling for error recovery # session.reconnect() not implemented; use close() and connect() for recovery

Custom Negotiation

Extend negotiation: .. code-block:: python

class CustomNegotiator(Negotiator):

async def negotiate_tn3270(self):

# Custom device type negotiation await super().negotiate_tn3270() await self._send_custom_query()

P3270 API Compatibility

Pure3270 implements a superset of the p3270 library API natively:

from pure3270 import P3270Client

# Drop-in replacement for p3270.P3270Client
session = P3270Client(hostName='host', hostPort=23)
session.connect()
session.sendEnter()
print(session.getScreen())
session.close()

# For existing code, simply change the import:
# from pure3270 import P3270Client as p3270

Performance Optimization

• Use buffer pools for large data streams

• Batch AID submissions

• Memory limits via RLIMIT_AS for resource-constrained environments