aprs-python/aprslib/parsing/message.py

135 lines
4.6 KiB
Python

import re
from aprslib.parsing import logger
from aprslib.parsing.telemetry import parse_telemetry_config
__all__ = [
'parse_message',
]
# MESSAGE PACKET
#
# :ADDRESSEE:Message text ........{XXXXX Up to 5 char line number
# :ADDRESSEE:ackXXXXX Ack for same line number
# :ADDRESSEE:Message text ........{MM}AA Line# with REPLY ACK
#
# TELEMETRY MESSAGES
#
# :N3MIM:PARM.Battery,BTemp,AirTemp,Pres,Altude,Camra,Chute,Sun,10m,ATV
# :N3MIM:UNIT.Volts,deg.F,deg.F,Mbar,Kfeet,Clik,OPEN!,on,on,high
# :N3MIM:EQNS.0,2.6,0,0,.53,-32,3,4.39,49,-32,3,18,1,2,3
# :N3MIM:BITS.10110101,PROJECT TITLE...
def parse_message(body):
parsed = {}
# the while loop is used to easily break out once a match is found
while True:
# try to match bulletin
match = re.findall(r"^BLN([0-9])([a-z0-9_ \-]{5}):(.{0,67})", body, re.I)
if match:
bid, identifier, text = match[0]
identifier = identifier.rstrip(' ')
mformat = 'bulletin' if identifier == "" else 'group-bulletin'
parsed.update({
'format': mformat,
'message_text': text.strip(' '),
'bid': bid,
'identifier': identifier
})
break
# try to match announcement
match = re.findall(r"^BLN([A-Z])([a-zA-Z0-9_ \-]{5}):(.{0,67})", body)
if match:
aid, identifier, text = match[0]
identifier = identifier.rstrip(' ')
parsed.update({
'format': 'announcement',
'message_text': text.strip(' '),
'aid': aid,
'identifier': identifier
})
break
# validate addresse
match = re.findall(r"^([a-zA-Z0-9_ \-]{9}):(.*)$", body)
if not match:
break
addresse, body = match[0]
parsed.update({'addresse': addresse.rstrip(' ')})
# check if it's a telemetry configuration message
body, result = parse_telemetry_config(body)
if result:
parsed.update(result)
break
# regular message
# ---------------------------
logger.debug("Packet is just a regular message")
parsed.update({'format': 'message'})
# APRS supports two different message formats:
# - the standard format which is described in 'aprs101.pdf':
# http://www.aprs.org/doc/APRS101.PDF
# - an addendum from 1999 which introduces a new format:
# http://www.aprs.org/aprs11/replyacks.txt
#
# A message (ack/rej as well as a standard msg text body) can either have:
# - no message number at all
# - a message number in the old format (1..5 characters / digits)
# - a message number in the new format (2 characters / digits) without trailing 'ack msg no'
# - a message number in the new format with trailing 'free ack msg no' (2 characters / digits)
# ack / rej
# ---------------------------
# NEW REPLAY-ACK
# format: :AAAABBBBC:ackMM}AA
match = re.findall(r"^(ack|rej)([A-Za-z0-9]{2})}([A-Za-z0-9]{2})?$", body)
if match:
parsed['response'], parsed['msgNo'], ackMsgNo = match[0]
if ackMsgNo:
parsed['ackMsgNo'] = ackMsgNo
break
# ack/rej standard format as per aprs101.pdf chapter 14
# format: :AAAABBBBC:ack12345
match = re.findall(r"^(ack|rej)([A-Za-z0-9]{1,5})$", body)
if match:
parsed['response'], parsed['msgNo'] = match[0]
break
# regular message body parser
# ---------------------------
parsed['message_text'] = body.strip(' ')
# check for ACKs
# new message format: http://www.aprs.org/aprs11/replyacks.txt
# format: :AAAABBBBC:text.....{MM}AA
match = re.findall(r"{([A-Za-z0-9]{2})}([A-Za-z0-9]{2})?$", body)
if match:
msgNo, ackMsgNo = match[0]
parsed['message_text'] = body[:len(body) - 4 - len(ackMsgNo)].strip(' ')
parsed['msgNo'] = msgNo
if ackMsgNo:
parsed['ackMsgNo'] = ackMsgNo
break
# old message format - see aprs101.pdf.
# search for: msgNo present
match = re.findall(r"{([A-Za-z0-9]{1,5})$", body)
if match:
msgNo = match[0]
parsed['message_text'] = body[:len(body) - 1 - len(msgNo)].strip(' ')
parsed['msgNo'] = msgNo
break
# break free from the eternal 'while'
break
return ('', parsed)