GPS from a BELABOX

#!/bin/sh
# irlmap.live installer for BELABOX (or any Linux box that uses ModemManager).
# Made by irlmap.live. Not part of, affiliated with or endorsed by the BELABOX project.
#
# Sends the GPS position from your modem to irlmap.live every 2 seconds.
#
#   Install:    curl -fsSL https://irlmap.live/install/belabox.sh | sudo sh
#   With token: curl -fsSL https://irlmap.live/install/belabox.sh | sudo sh -s -- in_yourtoken
#   Remove:     curl -fsSL https://irlmap.live/install/belabox.sh | sudo sh -s -- --uninstall
#
# What it installs:
#   /etc/irlmap-gps.conf                    your token (readable by root only)
#   /usr/local/bin/irlmap-gps               the sender
#   /etc/systemd/system/irlmap-gps.service  starts it at boot, restarts it if it stops
set -eu

URL="https://irlmap.live"
CONF="/etc/irlmap-gps.conf"
BIN="/usr/local/bin/irlmap-gps"
UNIT="/etc/systemd/system/irlmap-gps.service"

say()  { printf '%s\n' "$*"; }
step() { printf '\n\033[1m==> %s\033[0m\n' "$*"; }
die()  { printf '\n\033[31mError:\033[0m %s\n' "$*" >&2; exit 1; }

# Questions come from the terminal even though the script itself arrives through a pipe.
ask() {
  printf '%s' "$1" >/dev/tty
  read -r REPLY </dev/tty || REPLY=""
}

# ---------------------------------------------------------------- uninstall
if [ "${1:-}" = "--uninstall" ]; then
  [ "$(id -u)" -eq 0 ] || die "Run it with sudo."
  systemctl disable --now irlmap-gps 2>/dev/null || true
  rm -f "$UNIT" "$BIN" "$CONF"
  systemctl daemon-reload 2>/dev/null || true
  say "irlmap.live GPS sender removed."
  exit 0
fi

say ""
say "irlmap.live GPS installer"
say "Sends your modem's GPS to irlmap.live. Only used while you're live on Twitch."

# ---------------------------------------------------------------- checks
[ "$(id -u)" -eq 0 ] || die "Run it with sudo:  curl -fsSL $URL/install/belabox.sh | sudo sh"
command -v mmcli >/dev/null 2>&1 || die "mmcli (ModemManager) wasn't found. This installer needs a modem managed by ModemManager, which is what BELABOX uses."
command -v curl  >/dev/null 2>&1 || die "curl wasn't found. Install it first (apt install curl)."

# ---------------------------------------------------------------- find a GPS modem
step "Looking for a modem with GPS"
GPS_MODEM=""
for m in $(mmcli -L 2>/dev/null | sed -n 's|.*/Modem/\([0-9]*\).*|\1|p'); do
  name=$(mmcli -L 2>/dev/null | sed -n "s|.*/Modem/$m \(.*\)|\1|p")
  if mmcli -m "$m" --location-status 2>/dev/null | grep -q 'gps-raw'; then
    say "  Modem $m: $name  (has GPS)"
    [ -n "$GPS_MODEM" ] || GPS_MODEM="$m"
  else
    say "  Modem $m: $name  (no GPS)"
  fi
done
[ -n "$GPS_MODEM" ] || die "None of your modems report GPS support. Check that the modem has a GNSS receiver, or send GPS from your phone instead: $URL/guides/phone-gps-irl-stream"

# ---------------------------------------------------------------- token
step "Your ingest token"
TOKEN="${1:-}"
if [ -z "$TOKEN" ]; then
  say "Find it on $URL/settings under \"GPS apps and devices\". It starts with in_"
  ask "Paste your ingest token: "
  TOKEN=$(printf '%s' "$REPLY" | tr -d '[:space:]')
fi
case "$TOKEN" in in_?*) ;; *) die "That doesn't look like an ingest token. It should start with in_" ;; esac

# An empty post is accepted by a valid token and rejected (401) by anything else.
code=$(curl -s -o /dev/null -w '%{http_code}' -m 10 -X POST "$URL/ingest" \
  -H "Authorization: Bearer $TOKEN" -H "Content-Type: application/json" -d '{}' || true)
case "$code" in
  200) say "  Token works." ;;
  401) die "irlmap.live doesn't know that token. Copy it again from $URL/settings (it changes if you rotate it)." ;;
  *)   die "Couldn't reach irlmap.live (HTTP $code). Check the box has internet and try again." ;;
esac

# ---------------------------------------------------------------- install
step "Installing"
mkdir -p "$(dirname "$CONF")" "$(dirname "$BIN")" "$(dirname "$UNIT")"
umask 077
printf 'TOKEN=%s\nURL=%s\n' "$TOKEN" "$URL" > "$CONF"
umask 022

cat > "$BIN" <<'SENDER'
#!/bin/sh
# irlmap.live GPS sender. Reads the modem's GPS through ModemManager and posts it every 2 s.
# Settings live in /etc/irlmap-gps.conf. Installed by https://irlmap.live/install/belabox.sh
. /etc/irlmap-gps.conf
MODEM=""
n=0

# Modem numbers change when a modem resets, so look the GPS modem up again whenever needed.
find_modem() {
  for m in $(mmcli -L 2>/dev/null | sed -n 's|.*/Modem/\([0-9]*\).*|\1|p'); do
    if mmcli -m "$m" --location-status 2>/dev/null | grep -q 'gps-raw'; then MODEM="$m"; return 0; fi
  done
  MODEM=""
  return 1
}

while true; do
  if [ -z "$MODEM" ] || [ $((n % 30)) -eq 0 ]; then
    # Find the modem and (re)enable GPS about once a minute: a modem reset turns it off again.
    if find_modem; then
      mmcli -m "$MODEM" --location-enable-gps-raw --location-enable-gps-nmea >/dev/null 2>&1 || true
    fi
  fi
  n=$((n + 1))

  if [ -n "$MODEM" ]; then
    LOC=$(mmcli -m "$MODEM" --location-get 2>/dev/null || true)
    LAT=$(echo "$LOC" | sed -n 's/.*latitude: *\([-0-9.]*\).*/\1/p' | head -1)
    LON=$(echo "$LOC" | sed -n 's/.*longitude: *\([-0-9.]*\).*/\1/p' | head -1)
    ALT=$(echo "$LOC" | sed -n 's/.*altitude: *\([-0-9.]*\).*/\1/p' | head -1)
    if [ -n "$LAT" ] && [ -n "$LON" ]; then
      BODY="{\"lat\":$LAT,\"lon\":$LON"
      [ -n "$ALT" ] && BODY="$BODY,\"alt\":$ALT"
      BODY="$BODY}"
      curl -s -m 5 -X POST "$URL/ingest" -H "Authorization: Bearer $TOKEN" \
        -H "Content-Type: application/json" -d "$BODY" >/dev/null 2>&1 || true
    fi
  else
    MODEM=""
  fi
  sleep 2
done
SENDER
chmod 755 "$BIN"

cat > "$UNIT" <<'UNITFILE'
[Unit]
Description=Send GPS to irlmap.live
After=ModemManager.service network-online.target
Wants=network-online.target

[Service]
ExecStart=/usr/local/bin/irlmap-gps
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target
UNITFILE

mmcli -m "$GPS_MODEM" --location-enable-gps-raw --location-enable-gps-nmea >/dev/null 2>&1 || true
mmcli -m "$GPS_MODEM" --location-set-gps-refresh-rate=1 >/dev/null 2>&1 || true
systemctl daemon-reload
systemctl enable --now irlmap-gps >/dev/null 2>&1 || systemctl restart irlmap-gps
say "  Service irlmap-gps installed and running."

# ---------------------------------------------------------------- first fix
step "Waiting for a GPS fix (up to 2 minutes, it helps to be outside)"
i=0
while [ $i -lt 24 ]; do
  LOC=$(mmcli -m "$GPS_MODEM" --location-get 2>/dev/null || true)
  LAT=$(echo "$LOC" | sed -n 's/.*latitude: *\([-0-9.]*\).*/\1/p' | head -1)
  if [ -n "$LAT" ]; then
    say "  Got a fix. Your position is being sent to irlmap.live."
    break
  fi
  i=$((i + 1))
  printf '.'
  sleep 5
done
if [ $i -ge 24 ]; then
  say ""
  say "  No fix yet. That's normal indoors. The service keeps trying in the background."
  say "  Satellites visible but never a position? See \"Sees satellites but never gets a position\""
  say "  on $URL/guides/belabox-gps-setup"
fi

say ""
say "Done. Locations only count while you're live on Twitch, so the service can run all the time."
say "Check it's arriving under Settings on $URL (the green connection check)."
say "Status:  systemctl status irlmap-gps      Remove:  curl -fsSL $URL/install/belabox.sh | sudo sh -s -- --uninstall"