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