iR-APRSISD/ir-aprsisd
2021-03-25 23:03:37 -05:00

215 lines
7 KiB
Python
Executable file

#!/usr/bin/python3
############################################################################
##
## ir-aprsisd
##
## This is a KML-feed to APRS-IS forwarding daemon. It was written
## for Garmin/DeLorme inReach devices, but might work elsewhere too.
## It polls a KML feed in which it expects to find a point in rougly
## the form that the inReach online feeds use, with attendant course
## and altitude data. It transfers each new point found there to
## APRS-IS.
##
## K0SIN
##
###########################################################################
import aprslib
import urllib.request
import xml.dom.minidom
import time, calendar, math, re
import platform, sys
import configparser
from optparse import OptionParser
#Name of our configuration file.
cf = "ir-aprsisd.cfg"
#Configuration
conf = configparser.ConfigParser()
#Try /etc, then try the current directory, or just quit.
try:
conf.read("/etc/" + cf)
if not conf.has_section('General'):
conf.read(cf)
if not conf.has_section('General'):
sys.exit("Can't read configuration file: " + cf)
except:
sys.exit("Can't read configuration file: " + cf)
#Command-line options
op = OptionParser()
op.add_option("-s","--ssid",action="store",type="string",dest="ssid",help="APRS SSID")
op.add_option("-p","--pass",action="store",type="int",dest="passwd",help="APRS-IS password")
op.add_option("-P","--port",action="store",type="int",dest="port",help="APRS-IS port")
op.add_option("-u","--user",action="store",type="string",dest="user",help="inReach username")
op.add_option("-U","--url",action="store",type="string",dest="url",help="URL for KML feed")
op.add_option("-c","--comment",action="store",type="string",dest="comment",help="APRS-IS location beacon comment text")
op.add_option("-d","--delay",action="store",type="int",dest="delay",help="Delay between polls of KML feed")
(opts,args) = op.parse_args()
#Allow command-line arguments to override the config file.
if opts.ssid:
conf['APRS']['SSID'] = opts.ssid
if opts.passwd:
conf['APRS']['Password'] = str(opts.passwd)
if opts.port:
conf['APRS']['Port'] = str(opts.port)
if opts.user:
conf['inReach']['User'] = opts.user
if opts.url:
conf['inReach']['URL'] = opts.url
if opts.comment:
conf['APRS']['Comment'] = opts.comment
if opts.delay:
conf['General']['Period'] = opts.delay
#The beginning of our APRS packets should contain a source, path,
# q construct, and gateway address. We'll reuse the same SSID as a gate.
ARPreamble = ''.join([conf['APRS']['SSID'],'>APRS,','TCPIP*,','qAS,',conf['APRS']['SSID']])
NAME = "iR-APRSISD"
REV = "0.1"
#Start with the current time. We use this to keep track of whether we've
# already sent a position, so if we cut it off when the program starts, we
# won't (re-)send old stale entry from inReach
lastUpdate = calendar.timegm(time.gmtime())
#Handle connection to APRS-IS
def reconnect():
global AIS
while True:
AIS = aprslib.IS(conf['APRS']['SSID'],passwd=conf['APRS']['Password'],port=conf['APRS']['Port'])
try:
AIS.connect()
break
except Exception as e:
print("Trouble connecting to APRS-IS server.")
print(e)
#APRS-IS Setup
AIS = None
reconnect()
while True:
try:
KML = urllib.request.urlopen(conf['inReach']['URL']).read()
except Exception as e:
print(''.join(["Error reading URL: ", conf['inReach']['URL']]))
continue
try:
data = xml.dom.minidom.parseString(KML).documentElement
#The first placemark will have the expanded current location information.
position = data.getElementsByTagName('Placemark')[0]
#Now process the extended data into something easier to handle.
extended = {}
for xd in position.getElementsByTagName('ExtendedData')[0].getElementsByTagName('Data'):
if not xd.getElementsByTagName('value')[0].firstChild == None:
extended[xd.getAttribute('name')] = xd.getElementsByTagName('value')[0].firstChild.nodeValue
except Exception as e:
print(''.join(["Could not parse data from URL: ",conf['inReach']['URL']]))
continue
try:
#Here is the position vector
latitude = extended['Latitude']
longitude = extended['Longitude']
elevation = extended['Elevation']
velocity = extended['Velocity']
course = extended['Course']
uttime = extended['Time UTC']
device = extended['Device Type']
#Some time conversions. First the time struct.
ts = time.strptime(''.join([uttime," UTC"]),"%m/%d/%Y %I:%M:%S %p %Z")
#Unix epoch time for local record-keeping.
etime = calendar.timegm(ts)
#MonthDayHoursMinutes_z for APRS-IS packet
aprstime = time.strftime("%d%H%Mz",ts)
#Skip this one if it's old.
if lastUpdate > etime:
time.sleep(conf.getfloat('General','Period'))
continue
#Append the device type to the comment
conf['APRS']['Comment'] = ''.join([" ",conf['APRS']['Comment']," : ", NAME," v",REV," : ",platform.system()," on ",platform.machine()," : ",device])
#Latitude conversion
#We start with the truncated degrees, filled to two places
# then add fractional minutes two 2x2 digits.
latitude = float(latitude)
aprslat = str(abs(math.trunc(latitude))).zfill(2)
aprslat += '{:.02f}'.format(round((abs(latitude)-abs(math.trunc(latitude)))*60,2)).zfill(5)
if latitude > 0:
aprslat += "N"
else:
aprslat += "S"
#Longitude next.
longitude = float(longitude)
aprslong = str(abs(math.trunc(longitude))).zfill(3)
aprslong += '{:.02f}'.format(round((abs(longitude)-abs(math.trunc(longitude)))*60,2)).zfill(5)
if longitude > 0:
aprslong += "E"
else:
aprslong += "W"
#Altitude needs to be in feet above sea-level
# what we get instead is a string with a number of meters
# at the beginning.
aprsalt = re.sub(r'^(\d+\.?\d+)\s*m.*',r'\1',elevation)
#We need integer feet, six digits
aprsalt = str(round(float(aprsalt) * 3.2808399)).zfill(6)
aprsalt = "/A=" + aprsalt[0:6]
#Aprs position
aprspos = ''.join([aprslat,conf['APRS']['Separator'],aprslong,conf['APRS']['Symbol']])
#Course is already in degrees, so we just need to reformat it.
aprscourse = str(round(float(re.sub(r'(\d+\.?\d+).*',r'\1', course)))).zfill(3)
#Speed is in km/h.
aprsspeed = float(re.sub(r'(\d+\.?\d+).*',r'\1',velocity))*0.53995681
aprsspeed = str(min(round(aprsspeed),999)).zfill(3)
#Here's the course/speed combination
aprscs = ''.join([aprscourse,'/',aprsspeed])
except Exception as e:
print("Some relevant position vector data is missing or malformatted in this record.")
print(e)
#Pass? Maybe...
pass
try:
#According to spec, one valid format for location beacons is
# @092345z/4903.50N/07201.75W>088/036
# with a comment on the end that can include altitude and other
# information.
aprsPacket = ''.join([ARPreamble,':@',aprstime,aprspos,aprscs,aprsalt,conf['APRS']['Comment']])
print(aprsPacket)
#This will throw an exception if the packet is somehow wrong.
aprslib.parse(aprsPacket)
AIS.sendall(aprsPacket)
lastUpdate = etime
except Exception as e:
print("Could not send the update: ")
if 'aprsPacket' in locals():
print(aprsPacket)
print(e)
print("Attempting reconnection, just in case.")
reconnect()
pass
time.sleep(conf.getfloat('General','Period'))