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fix(system-health-check): add additional time providers and update URLs of existing providers (#2611)
* feat(system-health): add NTP and HTTP header time providers * test(system-health): add unit tests for system clock providers * chore(deps): add ntp package dependency and reorder imports * refactor(system-health): rename events & move logging init to bootstrap * fix(system-health): add binance time provider for web CORS rules block accessing the `date` header on web from other domains unless it's been explicitly allowed. * refactor: change method return type and implement ai review suggestions * fix(system-health): show banner if clock invalid even if peers >= 2 previous check was a regression that wouldn't show the banner for incorrect clock if there were still peers connected * refactor: simplify datetime parsing and revert exception regression * refactor: remove shared http client to avoid issues with multiple closes
1 parent 5a6ad28 commit 47300e1

26 files changed

+1019
-131
lines changed

‎lib/bloc/app_bloc_root.dart‎

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@@ -284,7 +284,8 @@ class AppBlocRoot extends StatelessWidget {
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),
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),
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BlocProvider<SystemHealthBloc>(
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create: (_) => SystemHealthBloc(SystemClockRepository(), mm2Api),
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create: (_) => SystemHealthBloc(SystemClockRepository(), mm2Api)
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..add(SystemHealthPeriodicCheckStarted()),
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),
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BlocProvider<TrezorInitBloc>(
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create: (context) => TrezorInitBloc(
@@ -300,7 +301,8 @@ class AppBlocRoot extends StatelessWidget {
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),
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),
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BlocProvider<FaucetBloc>(
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create: (context) => FaucetBloc(kdfSdk: context.read<KomodoDefiSdk>()),
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create: (context) =>
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FaucetBloc(kdfSdk: context.read<KomodoDefiSdk>()),
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)
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],
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child: _MyAppView(),

‎lib/bloc/system_health/providers/binance_time_provider.dart‎

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import 'dart:async' show TimeoutException;
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import 'dart:convert';
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import 'dart:io';
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import 'package:http/http.dart' as http;
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import 'package:logging/logging.dart';
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import 'package:web_dex/bloc/system_health/providers/time_provider.dart';
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/// A time provider that fetches time from the Binance API
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class BinanceTimeProvider extends TimeProvider {
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BinanceTimeProvider({
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this.url = 'https://api.binance.com/api/v3/time',
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http.Client? httpClient,
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this.timeout = const Duration(seconds: 2),
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this.maxRetries = 3,
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Logger? logger,
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}) : _httpClient = httpClient ?? http.Client(),
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_logger = logger ?? Logger('BinanceTimeProvider');
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/// The URL of the Binance time API
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final String url;
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/// Timeout for HTTP requests
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final Duration timeout;
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/// Maximum retries
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final int maxRetries;
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/// Logger instance
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final Logger _logger;
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/// HTTP client for making requests
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final http.Client _httpClient;
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@override
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String get name => 'Binance';
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@override
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Future<DateTime> getCurrentUtcTime() async {
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int retries = 0;
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while (retries < maxRetries) {
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try {
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final serverTime = await _fetchServerTime();
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_logger.fine('Successfully retrieved time from Binance API');
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return serverTime;
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} on SocketException catch (e, s) {
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_logger.warning('Socket error with Binance API', e, s);
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} on TimeoutException catch (e, s) {
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_logger.warning('Timeout with Binance API', e, s);
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} on FormatException catch (e, s) {
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_logger.severe('Failed to parse response from Binance API', e, s);
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} on Exception catch (e, s) {
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_logger.severe('Error fetching time from Binance API', e, s);
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}
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retries++;
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// Calculate exponential backoff: 100ms, 200ms, 400ms, 800ms...
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if (retries < maxRetries) {
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final delayDuration = Duration(milliseconds: 100 * (1 << retries));
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await Future<void>.delayed(delayDuration);
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}
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}
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_logger.severe(
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'Failed to get time from Binance API after $maxRetries retries',
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);
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throw TimeoutException(
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'Failed to get time from Binance API after $maxRetries retries',
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);
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}
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/// Fetches server time from the Binance API
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Future<DateTime> _fetchServerTime() async {
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final response = await _httpClient.get(Uri.parse(url)).timeout(timeout);
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if (response.statusCode != 200) {
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_logger.warning('HTTP error from $url: ${response.statusCode}');
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throw HttpException(
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'HTTP error from $url: ${response.statusCode}',
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uri: Uri.parse(url),
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);
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}
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final jsonData = jsonDecode(response.body) as Map<String, dynamic>;
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final serverTime = jsonData['serverTime'] as int?;
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if (serverTime == null) {
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throw const FormatException(
90+
'No serverTime field in Binance API response',
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);
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}
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return DateTime.fromMillisecondsSinceEpoch(serverTime, isUtc: true);
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}
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@override
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void dispose() {
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_httpClient.close();
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}
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}

‎lib/bloc/system_health/providers/http_head_time_provider.dart‎

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import 'dart:async' show TimeoutException;
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import 'dart:io';
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import 'dart:math' show Random;
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import 'package:http/http.dart' as http;
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import 'package:logging/logging.dart';
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import 'package:web_dex/bloc/system_health/providers/time_provider.dart';
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/// A time provider that fetches time from server 'Date' headers via HEAD requests
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class HttpHeadTimeProvider extends TimeProvider {
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HttpHeadTimeProvider({
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this.servers = const [
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'https://alibaba.com/',
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'https://google.com/',
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'https://cloudflare.com/',
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'https://microsoft.com/',
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'https://github.com/',
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],
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http.Client? httpClient,
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this.timeout = const Duration(seconds: 2),
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this.maxRetries = 3,
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Logger? logger,
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}) : _httpClient = httpClient ?? http.Client(),
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_logger = logger ?? Logger('HttpHeadTimeProvider');
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/// The name of the provider (for logging and identification)
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final Logger _logger;
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/// List of servers to query via HEAD requests
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final List<String> servers;
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/// Timeout for HTTP requests
33+
final Duration timeout;
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/// Maximum retries per server
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final int maxRetries;
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final http.Client _httpClient;
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@override
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String get name => 'HttpHead';
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@override
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Future<DateTime> getCurrentUtcTime() async {
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// Randomize the order of servers to avoid overloading any single server
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// and to provide a more even distribution of requests.
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// This also avoid a single server being a single point of failure.
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final shuffledServers = List<String>.from(servers)..shuffle(Random());
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_logger.fine('Randomized server order for time retrieval');
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for (final serverUrl in shuffledServers) {
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int retries = 0;
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while (retries < maxRetries) {
55+
try {
56+
final serverTime = await _fetchServerTime(serverUrl);
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_logger.fine('Successfully retrieved time from $serverUrl');
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return serverTime;
59+
} on SocketException catch (e, s) {
60+
_logger.warning('Socket error with $serverUrl', e, s);
61+
} on TimeoutException catch (e, s) {
62+
_logger.warning('Timeout with $serverUrl', e, s);
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} on HttpException catch (e, s) {
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_logger.warning('HTTP error with $serverUrl', e, s);
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} on FormatException catch (e, s) {
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_logger.warning('Date header parse error with $serverUrl', e, s);
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}
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retries++;
69+
}
70+
}
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_logger
73+
.severe('Failed to get time from any server after $maxRetries retries');
74+
throw TimeoutException(
75+
'Failed to get time from any server after $maxRetries retries',
76+
);
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}
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/// Fetches server time from the 'date' header of an HTTP HEAD response
80+
Future<DateTime> _fetchServerTime(String url) async {
81+
final response = await _httpClient.head(Uri.parse(url)).timeout(timeout);
82+
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// Treat any successful or redirect status as acceptable.
84+
if (response.statusCode < 200 || response.statusCode >= 400) {
85+
_logger.warning('HTTP error from $url: ${response.statusCode}');
86+
throw HttpException(
87+
'HTTP error from $url: ${response.statusCode}',
88+
uri: Uri.parse(url),
89+
);
90+
}
91+
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final dateHeader = response.headers['date'];
93+
if (dateHeader == null) {
94+
_logger.warning('No Date header in response from $url');
95+
throw FormatException('No Date header in response from $url');
96+
}
97+
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final parsed = HttpDate.parse(dateHeader);
99+
return parsed.toUtc();
100+
}
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102+
/// Disposes the HTTP client when done
103+
@override
104+
void dispose() {
105+
_httpClient.close();
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}
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}

‎lib/bloc/system_health/providers/http_time_provider.dart‎

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import 'dart:convert';
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import 'dart:io';
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import 'package:http/http.dart' as http;
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import 'package:logging/logging.dart';
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import 'package:web_dex/bloc/system_health/providers/time_provider.dart';
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8+
/// A time provider that fetches time from an HTTP API
9+
class HttpTimeProvider extends TimeProvider {
10+
HttpTimeProvider({
11+
required this.url,
12+
required this.timeFieldPath,
13+
required this.timeFormat,
14+
required String providerName,
15+
http.Client? httpClient,
16+
Duration? apiTimeout,
17+
Logger? logger,
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}) : _httpClient = httpClient ?? http.Client(),
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_apiTimeout = apiTimeout ?? const Duration(seconds: 2),
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name = providerName,
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_logger = logger ?? Logger(providerName);
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/// The URL of the time API
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final String url;
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/// The field path in the JSON response that contains the time.
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///
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/// Separate nested fields with dots (e.g., "time.current")
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final String timeFieldPath;
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/// The format of the time string in the response
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final TimeFormat timeFormat;
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/// The name of the provider (for logging and identification)
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@override
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final String name;
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final Logger _logger;
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final http.Client _httpClient;
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final Duration _apiTimeout;
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@override
44+
Future<DateTime> getCurrentUtcTime() async {
45+
final response = await _httpClient.get(Uri.parse(url)).timeout(_apiTimeout);
46+
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if (response.statusCode != 200) {
48+
_logger.warning('API request failed with status ${response.statusCode}');
49+
throw HttpException(
50+
'API request failed with status ${response.statusCode}',
51+
uri: Uri.parse(url),
52+
);
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}
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final dynamic decoded = json.decode(response.body);
56+
if (decoded is! Map<String, dynamic>) {
57+
_logger.warning(
58+
'Expected top-level JSON object, got ${decoded.runtimeType}',
59+
);
60+
throw const FormatException('Invalid JSON structure – object expected');
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}
62+
final Map<String, dynamic> jsonResponse = decoded;
63+
final parsedTime = await _parseTimeFromJson(jsonResponse);
64+
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return parsedTime;
66+
}
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Future<DateTime> _parseTimeFromJson(Map<String, dynamic> jsonResponse) async {
69+
final fieldParts = timeFieldPath.split('.');
70+
dynamic value = jsonResponse;
71+
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for (final part in fieldParts) {
73+
if (value is! Map<String, dynamic>) {
74+
_logger.warning('JSON path error: expected Map at $part');
75+
throw FormatException('JSON path error: expected Map at $part');
76+
}
77+
value = value[part];
78+
if (value == null) {
79+
_logger.warning('JSON path error: null value at $part');
80+
throw FormatException('JSON path error: null value at $part');
81+
}
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}
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final timeStr = value.toString();
85+
if (timeStr.isEmpty) {
86+
_logger.warning('Empty time string');
87+
throw const FormatException('Empty time string');
88+
}
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90+
return _parseDateTime(timeStr);
91+
}
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DateTime _parseDateTime(String timeStr) {
94+
switch (timeFormat) {
95+
case TimeFormat.iso8601:
96+
return DateTime.parse(timeStr).toUtc();
97+
case TimeFormat.custom:
98+
throw const FormatException('Custom time format not supported');
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}
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}
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@override
103+
void dispose() {
104+
_httpClient.close();
105+
}
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}
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/// Enum representing the format of time returned by the API
109+
enum TimeFormat {
110+
/// ISO8601 format (e.g. "2023-05-07T12:34:56Z")
111+
iso8601,
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/// Custom format that may require special parsing
114+
custom
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}

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