2 Lookaside backend to query local opencellid database
5 from configparser import ConfigParser
6 from sqlite3 import connect
7 from typing import Any, Dict, List, Tuple
9 __all__ = "init", "lookup"
14 def init(conf: ConfigParser) -> None:
16 ldb = connect(conf["opencellid"]["dbfn"])
25 mcc: int, mnc: int, gsm_cells: List[Tuple[int, int, int]], __: Any
26 ) -> Tuple[float, float]:
27 assert ldb is not None
29 lc.execute("""attach database ":memory:" as mem""")
30 lc.execute("create table mem.seen (locac int, cellid int, signal int)")
32 """insert into mem.seen (locac, cellid, signal)
38 """select c.lat, c.lon, s.signal
39 from main.cells c, mem.seen s
42 and c.cell = s.cellid""",
45 data = list(lc.fetchall())
46 # lc.execute("drop table mem.seen")
47 lc.execute("""detach database mem""")
50 raise ValueError("No location data found in opencellid")
51 sumsig = sum([1 / sig for _, _, sig in data])
52 nsigs = [1 / sig / sumsig for _, _, sig in data]
53 avlat = sum([lat * nsig for (lat, _, _), nsig in zip(data, nsigs)])
54 avlon = sum([lon * nsig for (_, lon, _), nsig in zip(data, nsigs)])