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, Resp
  13
  14 log = getLogger("gps303/lookaside")
  15
  16
  17 def runserver(conf):
  18     zctx = zmq.Context()
  19     zsub = zctx.socket(zmq.SUB)
  20     zsub.connect(conf.get("collector", "publishurl"))
  21     topic = pack("B", proto_by_name("WIFI_POSITIONING"))
  22     zsub.setsockopt(zmq.SUBSCRIBE, topic)
  23     zpush = zctx.socket(zmq.PUSH)
  24     zpush.connect(conf.get("collector", "listenurl"))
  25
  26     try:
  27         while True:
  28             zmsg = Bcast(zsub.recv())
  29             msg = parse_message(zmsg.packet)
  30             log.debug(
  31                 "IMEI %s from %s at %s: %s",
  32                 zmsg.imei,
  33                 zmsg.peeraddr,
  34                 datetime.fromtimestamp(zmsg.when).astimezone(tz=timezone.utc),
  35                 msg,
  36             )
  37             if not isinstance(msg, WIFI_POSITIONING):
  38                 log.error(
  39                     "IMEI %s from %s at %s: %s",
  40                     zmsg.imei,
  41                     zmsg.peeraddr,
  42                     datetime.fromtimestamp(zmsg.when).astimezone(
  43                         tz=timezone.utc
  44                     ),
  45                     msg,
  46                 )
  47                 continue
  48             lat, lon = qry_cell(
  49                 conf["opencellid"]["dbfn"], msg.mcc, msg.gsm_cells
  50             )
  51             resp = Resp(imei=zmsg.imei, packet=msg.Out(lat=lat, lon=lon).packed)
  52             log.debug("Response for lat=%s, lon=%s: %s", lat, lon, resp)
  53             zpush.send(resp.packed)
  54
  55     except KeyboardInterrupt:
  56         pass
  57
  58
  59 if __name__.endswith("__main__"):
  60     runserver(common.init(log))