latest

geolocate/geolocate.go

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+// Command geolocate estimates the machine's physical location by scanning
+// nearby Wi-Fi access points and submitting their BSSIDs to a public
+// Wi-Fi-to-location service, then records the result under ~/.data/location.
+//
+// This is a macOS port of the original Linux script. Two things changed since
+// the original was written:
+//
+//   - The original scanned access points with nmcli (NetworkManager). macOS
+//     has no equivalent, and Apple removed the `airport` CLI in macOS 14.4.
+//     On macOS 26, CoreWLAN only returns real BSSIDs to a Developer-ID-signed,
+//     notarized binary that the user has granted Location Services access. We
+//     get that via the macwifi package, which ships such a signed helper.
+//
+//   - The original queried Mozilla Location Services, which shut down in 2024.
+//     We use BeaconDB instead: a community-run successor that speaks the same
+//     Ichnaea API (identical request/response shape).
+package main
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/jaisonerick/macwifi"
+)
+
+// geolocateURL is BeaconDB's Ichnaea-compatible geolocate endpoint, the
+// drop-in replacement for the defunct location.services.mozilla.com.
+const geolocateURL = "https://api.beacondb.net/v1/geolocate"
+
+// accessPoint is one observed Wi-Fi access point in the Ichnaea request
+// schema. Only macAddress is required; signal strength and channel improve
+// the position estimate when available.
+type accessPoint struct {
+	MacAddress     string `json:"macAddress"`
+	SignalStrength int    `json:"signalStrength,omitempty"`
+	Channel        int    `json:"channel,omitempty"`
+}
+
+type geolocateRequest struct {
+	WifiAccessPoints []accessPoint `json:"wifiAccessPoints,omitempty"`
+}
+
+func main() {
+	if err := run(); err != nil {
+		fmt.Fprintln(os.Stderr, "geolocate:", err)
+		os.Exit(1)
+	}
+}
+
+func run() error {
+	ts := time.Now().Unix()
+
+	// The first scan triggers macOS's Location Services prompt for the
+	// bundled helper; allow generous time for a user to approve it.
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer cancel()
+
+	// Wi-Fi scanning requires Location Services. If it is disabled (or the
+	// scan otherwise fails), fall back to IP-based geolocation rather than
+	// aborting — matching the original, which posted an empty request when
+	// it couldn't find enough access points.
+	aps, err := listAccessPoints(ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr,
+			"geolocate: wifi scan unavailable (%v); falling back to IP geolocation\n", err)
+		aps = nil
+	}
+
+	loc, err := geolocate(aps)
+	if err != nil {
+		return err
+	}
+	loc["timestamp"] = ts
+
+	out, err := json.Marshal(loc)
+	if err != nil {
+		return err
+	}
+
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return err
+	}
+	dir := filepath.Join(home, ".data", "location")
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		return err
+	}
+
+	if err := writeFile(filepath.Join(dir, "latest.json"), out); err != nil {
+		return err
+	}
+	return writeFile(filepath.Join(dir, fmt.Sprintf("%d.json", ts)), out)
+}
+
+func writeFile(path string, content []byte) error {
+	return os.WriteFile(path, content, 0o644)
+}
+
+// listAccessPoints scans nearby Wi-Fi networks via CoreWLAN (through the
+// macwifi helper) and returns their BSSIDs. It returns nil if fewer than two
+// usable access points are found, mirroring the original script: the
+// geolocation service needs at least two observations to triangulate.
+func listAccessPoints(ctx context.Context) ([]accessPoint, error) {
+	networks, err := macwifi.Scan(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("scanning wifi: %w", err)
+	}
+
+	seen := make(map[string]bool)
+	var aps []accessPoint
+	for _, n := range networks {
+		// BSSID is empty when Location Services access has not been
+		// granted, or for saved-but-not-visible networks.
+		if n.BSSID == "" || seen[n.BSSID] {
+			continue
+		}
+		seen[n.BSSID] = true
+		aps = append(aps, accessPoint{
+			MacAddress:     n.BSSID,
+			SignalStrength: n.RSSI,
+			Channel:        n.Channel,
+		})
+	}
+
+	if len(aps) < 2 {
+		return nil, nil
+	}
+	return aps, nil
+}
+
+// geolocate posts the observed access points to BeaconDB and returns the
+// decoded response (e.g. {"location":{"lat":..,"lng":..},"accuracy":..}).
+// With no access points it degrades to a GeoIP estimate, matching the
+// original behaviour of posting an empty request.
+func geolocate(aps []accessPoint) (map[string]any, error) {
+	body, err := json.Marshal(geolocateRequest{WifiAccessPoints: aps})
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := http.Post(geolocateURL, "application/json", bytes.NewReader(body))
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	data, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("geolocation service returned %s: %s",
+			resp.Status, bytes.TrimSpace(data))
+	}
+
+	var result map[string]any
+	if err := json.Unmarshal(data, &result); err != nil {
+		return nil, err
+	}
+	return result, nil
+}