MLLP using asyncio

New in version 0.4.1.


hl7.mllp package is currently experimental and subject to change. It aims to replace txHL7.

python-hl7 includes classes for building HL7 clients and servers using asyncio. The underlying protocol for these clients and servers is MLLP.

The hl7.mllp package is designed the same as the asyncio.streams package. Examples in that documentation may be of assistance in writing production senders and receivers.

HL7 Sender

# Using the third party `aiorun` instead of the `` to avoid
# boilerplate.
import aiorun

import hl7
from hl7.mllp import open_hl7_connection

async def main():
    message = 'MSH|^~\&|GHH LAB|ELAB-3|GHH OE|BLDG4|200202150930||ORU^R01|CNTRL-3456|P|2.4\r'
    message += 'PID|||555-44-4444||EVERYWOMAN^EVE^E^^^^L|JONES|196203520|F|||153 FERNWOOD DR.^^STATESVILLE^OH^35292||(206)3345232|(206)752-121||||AC555444444||67-A4335^OH^20030520\r'
    message += 'OBR|1|845439^GHH OE|1045813^GHH LAB|1554-5^GLUCOSE|||200202150730||||||||555-55-5555^PRIMARY^PATRICIA P^^^^MD^^LEVEL SEVEN HEALTHCARE, INC.|||||||||F||||||444-44-4444^HIPPOCRATES^HOWARD H^^^^MD\r'
    message += 'OBX|1|SN|1554-5^GLUCOSE^POST 12H CFST:MCNC:PT:SER/PLAS:QN||^182|mg/dl|70_105|H|||F\r'

    # Open the connection to the HL7 receiver.
    # Using wait_for is optional, but recommended so
    # a dead receiver won't block you for long
    hl7_reader, hl7_writer = await asyncio.wait_for(
        open_hl7_connection("", 2575),

    hl7_message = hl7.parse(message)

    # Write the HL7 message, and then wait for the writer
    # to drain to actually send the message
    await hl7_writer.drain()
    print(f'Sent message\n {hl7_message}'.replace('\r', '\n'))

    # Now wait for the ACK message from the receiever
    hl7_ack = await asyncio.wait_for(
    print(f'Received ACK\n {hl7_ack}'.replace('\r', '\n')), stop_on_unhandled_errors=True)

HL7 Receiver

# Using the third party `aiorun` instead of the `` to avoid
# boilerplate.
import aiorun

import hl7
from hl7.mllp import start_hl7_server

async def process_hl7_messages(hl7_reader, hl7_writer):
    """This will be called every time a socket connects
    with us.
    peername = hl7_writer.get_extra_info("peername")
    print(f"Connection established {peername}")
        # We're going to keep listening until the writer
        # is closed. Only writers have closed status.
        while not hl7_writer.is_closing():
            hl7_message = await hl7_reader.readmessage()
            print(f'Received message\n {hl7_message}'.replace('\r', '\n'))
            # Now let's send the ACK and wait for the
            # writer to drain
            await hl7_writer.drain()
    except asyncio.IncompleteReadError:
        # Oops, something went wrong, if the writer is not
        # closed or closing, close it.
        if not hl7_writer.is_closing():
            await hl7_writer.wait_closed()
    print(f"Connection closed {peername}")

async def main():
        # Start the server in a with clause to make sure we
        # close it
        async with await start_hl7_server(
            process_hl7_messages, port=2575
        ) as hl7_server:
            # And now we server forever. Or until we are
            # cancelled...
            await hl7_server.serve_forever()
    except asyncio.CancelledError:
        # Cancelled errors are expected
    except Exception:
        print("Error occurred in main"), stop_on_unhandled_errors=True)