diet-guard/app/lib/services/token_vault_web.dart
Krzysztof kuhy Rudnicki 802ee0fe6d app: run the companion app's desktop target as a web build
Flutter's Linux embedder manages ~20fps at 3840x2160 -- measured on a stock
`flutter create` counter app, so it is the toolkit rather than this code --
where the same Dart rendered by Chrome sustains ~144fps (evidence in
~/todo/docs/desktop-performance-findings.md). The desktop target therefore
becomes a Flutter *web* build; Android is untouched.

`dart:io` does not fail a web *compile* -- it resolves to a stub that throws
at runtime -- so every platform edge moves behind a conditional export rather
than being discovered later as a blank white window:

- storage: `document_store*.dart`, files on Android and IndexedDB in the
  browser (mirrored to the desktop wrapper, which is what makes a wiped
  Chrome profile recoverable). Document names stay the exact pre-web
  filenames so an installed phone keeps reading its existing log.
- photos: `blob_store*.dart` plus `attached_image*.dart`, since `Image.file`
  cannot resolve an IndexedDB key. The picker itself has web support; what
  changed is the storage and display model. Camera *capture* is genuinely
  lost on desktop -- and photos never crossed devices anyway, `imagePath`
  being stripped before push.
- scheduling: `background_tasks*.dart`. A browser has no WorkManager
  equivalent -- a closed tab runs nothing -- so the desktop runs an in-page
  5-minute check while its window is open. That loses nothing on the PC,
  where `diet-guard-gate.timer` already locks the screen on an unlogged
  slot, which is strictly stronger than a notification.
- notifications: `notification_backend*.dart`, the browser Notifications API
  in place of flutter_local_notifications.
- the GitHub token: `token_vault*.dart`. On web it is *not* held by the
  browser at all -- flutter_secure_storage's web backend is WebCrypto-wrapped
  localStorage with the wrap key beside the ciphertext, which is obfuscation,
  not encryption at rest -- so the desktop wrapper owns it and proxies the
  API (`github_client_factory*.dart`).

`Platform.isAndroid` itself throws on web, so every platform branch now tests
`kIsWeb` first; the battery-optimization row (permission_handler, no web
implementation) is hidden off Android.

The desktop pushes under device id `desktop`, not `phone`: sharing an id
would have made the two devices overwrite each other's pushed log on every
tick. The Python side enumerates device directories generically, so it needs
no change.

Tests move onto the same seams -- the file-backed stores keep the atomicity
and unreadable-file guarantees where they belong.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-20 16:31:32 +02:00

66 lines
2.1 KiB
Dart

/// Wrapper-backed [TokenVault] for the desktop web build.
library;
import 'dart:convert';
import 'package:diet_guard_app/services/desktop_wrapper.dart';
import 'package:diet_guard_app/services/token_vault.dart';
import 'package:http/http.dart' as http;
/// Delegates token storage to the desktop wrapper.
///
/// The browser never holds the token: [read] reports only whether the wrapper
/// has one, and [write] hands a pasted PAT straight through to the wrapper's
/// 600-mode token file. This is deliberately *not* `flutter_secure_storage`'s
/// web backend, which is WebCrypto-wrapped `localStorage` with the wrap key
/// stored beside the ciphertext -- obfuscation, not encryption at rest.
class WrapperTokenVault implements TokenVault {
/// Creates a vault talking to the wrapper at [baseUrl].
WrapperTokenVault({this.baseUrl = desktopWrapperOrigin, http.Client? client})
: _client = client ?? http.Client();
/// Origin of the desktop wrapper.
final String baseUrl;
final http.Client _client;
@override
bool get exposesTokenValue => false;
@override
Future<String> read() async {
try {
final response = await _client.get(
Uri.parse('$baseUrl${WrapperPaths.github}auth/status'),
);
if (response.statusCode != 200) return '';
final body = jsonDecode(response.body);
final configured = body is Map && body['configured'] == true;
return configured ? wrapperManagedToken : '';
} on Exception {
// No wrapper running (a plain browser tab): behave as unconfigured
// rather than failing the whole settings screen.
return '';
}
}
@override
Future<bool> write(String token) async {
// The stand-in is what `read` handed out; writing it back would replace a
// real token with a literal.
if (token == wrapperManagedToken) return true;
try {
final response = await _client.post(
Uri.parse('$baseUrl${WrapperPaths.github}auth/token'),
body: token,
);
return response.statusCode == 204;
} on Exception {
return false;
}
}
}
/// Opens the platform token vault.
TokenVault openTokenVault() => WrapperTokenVault();