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randogoth 2025-02-27 15:24:16 +02:00
parent 2a093e3126
commit ac62865cd6
9 changed files with 408 additions and 384 deletions
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129
lib/rugreefer.dart
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@ -4,50 +4,126 @@ import 'package:http/http.dart' as http;
import 'package:dart_geohash/dart_geohash.dart';
import 'package:latlong2/latlong.dart';
import 'package:turf/turf.dart';
import 'package:path_provider/path_provider.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:flutter/foundation.dart' show kIsWeb;
class GeoMetadataLookup {
final String apiUrl;
final Directory cacheDir;
final bool enableCacheExpiration;
final Duration cacheExpirationDuration;
final Distance distance = const Distance();
final http.Client httpClient;
Directory? cacheDir;
GeoMetadataLookup({
required this.apiUrl,
required this.cacheDir,
}) {
if (!cacheDir.existsSync()) {
cacheDir.createSync(recursive: true);
this.enableCacheExpiration = false,
this.cacheExpirationDuration = const Duration(days: 14),
http.Client? client,
}) : httpClient = client ?? http.Client() {
_initCacheDir();
}
Future<void> _initCacheDir() async {
if (!kIsWeb) {
cacheDir = await getApplicationDocumentsDirectory();
if (enableCacheExpiration) {
await _cleanExpiredCache();
}
}
}
Future<List<Map<String, dynamic>>> lookup(double latitude, double longitude, {double distance = 10.0}) async {
final String geohash = GeoHasher().encode(longitude, latitude);
final File cacheFile = File('${cacheDir.path}/$geohash.geojson.gz');
Future<List<Map<String, dynamic>>> lookup(double latitude, double longitude, {double distanceThreshold = 10.0}) async {
final String geohash = GeoHasher().encode(latitude, longitude, precision: 4);
if (kIsWeb) {
return _lookupWeb(geohash);
} else {
return _lookupFile(geohash, latitude, longitude, distanceThreshold);
}
}
if (!cacheFile.existsSync()) {
Future<List<Map<String, dynamic>>> _lookupFile(String geohash, double latitude, double longitude, double distanceThreshold) async {
final File cacheFile = File('${cacheDir?.path}/$geohash.geojson.gz');
await _updateLastAccessTime(geohash);
final bool isExpired = await _isCacheExpired(geohash);
if (!cacheFile.existsSync() || isExpired) {
await _downloadGeoJson(geohash, cacheFile);
}
final String geoJsonStr = utf8.decode(GZipCodec().decode(cacheFile.readAsBytesSync()));
final Map<String, dynamic> geoJson = jsonDecode(geoJsonStr);
return _findMetadata(latitude, longitude, distance, geoJson);
return _findMetadata(latitude, longitude, geoJson, distanceThreshold);
}
Future<List<Map<String, dynamic>>> _lookupWeb(String geohash) async {
final prefs = await SharedPreferences.getInstance();
final String? cachedGeoJson = prefs.getString('geojson_$geohash');
if (cachedGeoJson == null || await _isCacheExpired(geohash)) {
final response = await http.get(Uri.parse('$apiUrl?geohash=$geohash&format=geojson'));
if (response.statusCode == 200) {
await prefs.setString('geojson_$geohash', utf8.decode(response.bodyBytes));
await _updateLastAccessTime(geohash);
return _findMetadata(0, 0, jsonDecode(utf8.decode(response.bodyBytes)), 10.0);
} else {
throw Exception('Failed to download GeoJSON for geohash: $geohash');
}
}
return _findMetadata(0, 0, jsonDecode(cachedGeoJson), 10.0);
}
Future<void> _downloadGeoJson(String geohash, File cacheFile) async {
final response = await http.get(Uri.parse('$apiUrl$geohash'));
if (response.statusCode == 200) {
cacheFile.writeAsBytesSync(GZipCodec().encode(response.bodyBytes));
} else {
throw Exception('Failed to download GeoJSON for geohash: $geohash');
final response = await httpClient.get(Uri.parse('$apiUrl?geohash=$geohash&format=geojson'));
if (response.statusCode == 200) {
cacheFile.writeAsBytesSync(GZipCodec().encode(response.bodyBytes));
await _updateLastAccessTime(geohash);
} else {
throw Exception('Failed to download GeoJSON for geohash: $geohash');
}
}
Future<void> _updateLastAccessTime(String geohash) async {
final prefs = await SharedPreferences.getInstance();
await prefs.setInt('cache_last_access_$geohash', DateTime.now().millisecondsSinceEpoch);
}
Future<bool> _isCacheExpired(String geohash) async {
if (!enableCacheExpiration) return false;
final prefs = await SharedPreferences.getInstance();
final int? lastAccess = prefs.getInt('cache_last_access_$geohash');
if (lastAccess == null) return true;
return DateTime.now().difference(DateTime.fromMillisecondsSinceEpoch(lastAccess)) > cacheExpirationDuration;
}
Future<void> _cleanExpiredCache() async {
final prefs = await SharedPreferences.getInstance();
final keys = prefs.getKeys().where((key) => key.startsWith('cache_last_access_')).toList();
for (var key in keys) {
final geohash = key.replaceFirst('cache_last_access_', '');
if (await _isCacheExpired(geohash)) {
final File cacheFile = File('${cacheDir?.path}/$geohash.geojson.gz');
if (cacheFile.existsSync()) {
cacheFile.deleteSync();
}
await prefs.remove(key);
}
}
}
List<Map<String, dynamic>> _findMetadata(double latitude, double longitude, double distanceThreshold, Map<String, dynamic> geoJson) {
List<Map<String, dynamic>> _findMetadata(double latitude, double longitude, Map<String, dynamic> geoJson, double distanceThreshold) {
final Position point = Position(longitude, latitude);
List<Map<String, dynamic>> results = [];
for (var feature in geoJson['features']) {
final geometry = feature['geometry'];
final properties = feature['properties'] ?? {};
final metadata = properties['tags']?.cast<String, dynamic>() ?? {};
metadata.removeWhere((key, value) => value == null);
if (geometry['type'] == 'Polygon') {
final polygon = Polygon(
@ -58,7 +134,7 @@ class GeoMetadataLookup {
.toList(),
);
if (booleanPointInPolygon(point, polygon)) {
results.add({'type': 'polygon', ...properties});
results.add({"type": "polygon", ...metadata});
}
}
@ -69,21 +145,7 @@ class GeoMetadataLookup {
.toList(),
);
if (_isPointNearLine(point, line, distanceThreshold)) {
results.add({'type': 'line', ...properties});
}
}
else if (geometry['type'] == 'MultiLineString') {
for (var lineCoords in geometry['coordinates']) {
final line = LineString(
coordinates: (lineCoords as List)
.map((p) => Position(p[0] as double, p[1] as double))
.toList(),
);
if (_isPointNearLine(point, line, distanceThreshold)) {
results.add({'type': 'multi_line', ...properties});
break;
}
results.add({"type": "line", ...metadata});
}
}
}
@ -91,8 +153,7 @@ class GeoMetadataLookup {
}
bool _isPointNearLine(Position point, LineString line, double distanceThreshold) {
for (var i = 0; i < line.coordinates.length - 1; i++) {
final p1 = line.coordinates[i];
for (var p1 in line.coordinates) {
final double dist = distance.distance(
LatLng(point.lat.toDouble(), point.lng.toDouble()),
LatLng(p1.lat.toDouble(), p1.lng.toDouble()),