gps303/lookaside.py

   1 """ Estimate coordinates from WIFI_POSITIONING and send back """
   2
   3 from datetime import datetime, timezone
   4 from logging import getLogger
   5 from os import umask
   6 from struct import pack
   7 import zmq
   8
   9 from . import common
  10 from .gps303proto import parse_message, proto_by_name, WIFI_POSITIONING
  11 from .opencellid import qry_cell
  12 from .zmsg import Bcast, LocEvt, Resp
  13
  14 log = getLogger("gps303/lookaside")
  15
  16
  17 def runserver(conf):
  18     zctx = zmq.Context()
  19     zpub = zctx.socket(zmq.PUB)
  20     oldmask = umask(0o117)
  21     zpub.bind(conf.get("lookaside", "publishurl"))
  22     umask(oldmask)
  23     zsub = zctx.socket(zmq.SUB)
  24     zsub.connect(conf.get("collector", "publishurl"))
  25     for protoname in (
  26         "GPS_POSITIONING",
  27         "WIFI_POSITIONING",
  28     ):
  29         topic = pack("B", proto_by_name(protoname))
  30         zsub.setsockopt(zmq.SUBSCRIBE, topic)
  31     zpush = zctx.socket(zmq.PUSH)
  32     zpush.connect(conf.get("collector", "listenurl"))
  33
  34     try:
  35         while True:
  36             zmsg = Bcast(zsub.recv())
  37             msg = parse_message(zmsg.packet)
  38             log.debug(
  39                 "IMEI %s from %s at %s: %s",
  40                 zmsg.imei,
  41                 zmsg.peeraddr,
  42                 datetime.fromtimestamp(zmsg.when).astimezone(tz=timezone.utc),
  43                 msg,
  44             )
  45             if isinstance(msg, WIFI_POSITIONING):
  46                 is_gps = False
  47                 lat, lon = qry_cell(
  48                     conf["opencellid"]["dbfn"], msg.mcc, msg.gsm_cells
  49                 )
  50                 resp = Resp(
  51                     imei=zmsg.imei, packet=msg.Out(lat=lat, lon=lon).packed
  52                 )
  53                 log.debug("Response for lat=%s, lon=%s: %s", lat, lon, resp)
  54                 zpush.send(resp.packed)
  55             else:
  56                 is_gps = True
  57                 lat = msg.latitude
  58                 lon = msg.longitude
  59             zpub.send(
  60                 LocEvt(
  61                     imei=zmsg.imei,
  62                     devtime=msg.devtime,
  63                     is_gps=is_gps,
  64                     lat=lat,
  65                     lon=lon,
  66                 ).packed
  67             )
  68
  69     except KeyboardInterrupt:
  70         pass
  71
  72
  73 if __name__.endswith("__main__"):
  74     runserver(common.init(log))