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         "GPS_OFFLINE_POSITIONING",
  28         "WIFI_POSITIONING",
  29     ):
  30         topic = pack("B", proto_by_name(protoname))
  31         zsub.setsockopt(zmq.SUBSCRIBE, topic)
  32     zpush = zctx.socket(zmq.PUSH)
  33     zpush.connect(conf.get("collector", "listenurl"))
  34
  35     try:
  36         while True:
  37             zmsg = Bcast(zsub.recv())
  38             msg = parse_message(zmsg.packet)
  39             log.debug(
  40                 "IMEI %s from %s at %s: %s",
  41                 zmsg.imei,
  42                 zmsg.peeraddr,
  43                 datetime.fromtimestamp(zmsg.when).astimezone(tz=timezone.utc),
  44                 msg,
  45             )
  46             if isinstance(msg, WIFI_POSITIONING):
  47                 is_gps = False
  48                 lat, lon = qry_cell(
  49                     conf["opencellid"]["dbfn"], msg.mcc, msg.gsm_cells
  50                 )
  51                 resp = Resp(
  52                     imei=zmsg.imei, packet=msg.Out(lat=lat, lon=lon).packed
  53                 )
  54                 log.debug("Response for lat=%s, lon=%s: %s", lat, lon, resp)
  55                 zpush.send(resp.packed)
  56             else:
  57                 is_gps = True
  58                 lat = msg.latitude
  59                 lon = msg.longitude
  60             zpub.send(
  61                 LocEvt(
  62                     imei=zmsg.imei,
  63                     devtime=msg.devtime,
  64                     is_gps=is_gps,
  65                     lat=lat,
  66                     lon=lon,
  67                 ).packed
  68             )
  69
  70     except KeyboardInterrupt:
  71         pass
  72
  73
  74 if __name__.endswith("__main__"):
  75     runserver(common.init(log))