iR-APRSISD/ir-aprsisd

#!/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"

#Command-line options
op = OptionParser()

op.add_option("-C","--config",action="store",type="string",dest="config",help="Load the named configuration file.")
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("--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("-P","--irpass",action="store",type="string",dest="irpass",help="inReach feed password")
op.add_option("-U","--url",action="store",type="string",dest="url",help="URL for KML feed")
op.add_option("-i","--imei",action="store",type="int",dest="imei",help="This instance should watch *only* for the single IMEI given in this option.  For a more complicated mapping, use the Device section in the configuration file.")
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()

#This needs to be defined before the load below happens.
#Load a configuration file, and try to validate that it is loaded.
def loadConfig(cfile):
	global conf
	conf = configparser.ConfigParser()
	if conf.read(cfile):
		if conf.has_section('General'):
			return True
	return False


#Handle loading of the configuration file first.
#Other command-line options may override things defined in the file.
if opts.config:
	if not loadConfig(opts.config):
		print("Can't load configuration: " + opts.config)
		sys.exit(1)
else:	#Default behavior if no file specified.
	if not loadConfig("/etc/" + cf):
		if not loadConfig(cf):
			print("Can't find default configuration: " + cf)
			sys.exit(1)

#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.irpass:
	conf['inReach']['Password'] = 	opts.irpass
if opts.url:
	conf['inReach']['URL'] = 	opts.url
if opts.comment:
	conf['APRS']['Comment'] =	opts.comment
if opts.delay:
	conf['General']['Period'] =	opts.delay


#Handle the special case where we've specified an IMEI on the command-line
if opts.imei:
	conf['Devices'] = {}
	conf['Devices'][conf['APRS']['SSID']] = str(opts.imei)

#Get the number and call from from the default SSID
#If we have multiple devices with non-specific ID mapping, we'll make it up
# from this.
(Call,SSNum) = re.search('(\w+)-(\d+)$',conf['APRS']['SSID']).groups()
SSNum = int(SSNum)

#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.
# This is the part between the source and the gate.
ARPreamble	= ''.join(['>APRS,','TCPIP*,','qAS,',conf['APRS']['SSID']])

NAME		= "iR-APRSISD"
REV		= "0.2"

#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())


#Set up the handler for HTTP connections
if conf.has_option('inReach','Password'):
	passman		= urllib.request.HTTPPasswordMgrWithDefaultRealm()
	passman.add_password(None, conf['inReach']['URL'],'',conf['inReach']['Password'])
	httpauth	= urllib.request.HTTPBasicAuthHandler(passman)
	http		= urllib.request.build_opener(httpauth)
else:
	http		= urllib.request.build_opener()
urllib.request.install_opener(http)

#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)

#We'll store the IMEI to ssid mapping here.
SSIDList = {}
#We'll store timestamps here
lastUpdate = {}

#Load any preconfigured IMEI mappings
if conf.has_section('Devices'):
	for device in conf['Devices'].keys():
		SSIDList[conf['Devices'][device]] = device.upper()
		

#Get an SSID
def getSSID(IMEI):
	global lastUpdate, SSIDList, SSNum, Call
	#If we have a Devices section, the SSID list is static.
	if IMEI not in SSIDList:
		if conf.has_section('Devices'):
			return None
		SSIDList[IMEI] = ''.join([Call,"-",str(SSNum)])
		SSNum = SSNum + 1
	#Add a timestamp on the first call
	# This prevents us from redelivering an old message, which can stay
	# in the feed.
	if IMEI not in lastUpdate:
		lastUpdate[IMEI] = calendar.timegm(time.gmtime())
	return SSIDList[IMEI]


#APRS-IS Setup
AIS = None
reconnect()

#Generate an APRS packet from a Placemark
def sendAPRS(Placemark):
	#We only care about the Placemarks with the ExtendedData sections.
	if not Placemark.getElementsByTagName('ExtendedData'):
		return None
		
	#Now process the extended data into something easier to handle.
	extended = {}
	for xd in Placemark.getElementsByTagName('ExtendedData')[0].getElementsByTagName('Data'):
		if not xd.getElementsByTagName('value')[0].firstChild == None:
			extended[xd.getAttribute('name')] = xd.getElementsByTagName('value')[0].firstChild.nodeValue	
	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']
		IMEI		= extended['IMEI']
		SSID		= getSSID(IMEI)

		#If there's no valid SSID mapping, we don't process this one.
		if not SSID:
			return None

		#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[IMEI] > etime:
			time.sleep(conf.getfloat('General','Period'))
			return None

		#If we have SMS data, add that.
		if 'Text' in extended:
			comment = extended['Text']
		else:	#Default comment
			comment = conf['APRS']['Comment']
		comment = ''.join([" ", comment, " : ", NAME, " v", REV, " : ", platform.system(), " on ", platform.machine(), " : ", device])
		#In the format we're using, APRS comments can be 36 characters
		# ... but APRS-IS doesn't seem to care, so leave this off.
		#comment = comment[:36]

		#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([getSSID(IMEI),ARPreamble,':@',aprstime,aprspos,aprscs,aprsalt,comment])
		#This will throw an exception if the packet is somehow wrong.
		aprslib.parse(aprsPacket)
		AIS.sendall(aprsPacket)
		lastUpdate[IMEI] = etime
		return aprsPacket

	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

while True:
	try:
		KML = http.open(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
	except Exception as e:
		print("Can't process KML feed on this pass.")
		continue
	#The first placemark will have the expanded current location information.
	for PM in data.getElementsByTagName('Placemark'):
		sendAPRS(PM)
	time.sleep(conf.getfloat('General','Period'))