MobileMonitor (Claude Edition)

A Flutter network-monitoring app that checks the availability and status of URLs, DNS hosts, and Certificate Revocation Lists (CRLs), with SSL/CRL expiry tracking. This is a re-engineered fork of jgoodloe/MobileMonitor focused on performance, architecture, and maintainability while preserving all original behavior and defaults.

See REVIEW.md for the full code review, the specific performance issues found in the original, and what changed here.

What's new vs. the original

• Concurrent monitoring. URL, DNS, and CRL groups run in parallel instead of one long sequential pass, so a refresh takes about as long as the slowest group rather than the sum of all three.
• State extracted from the UI. A MonitorController (ChangeNotifier) owns all orchestration and state; the screen just renders it. The original drove everything through setState inside the widget.
• No print() in the hot path. The CRL parser shed ~120 debug print() calls that previously ran on every parse (including release builds). Diagnostics now flow through structured logging and the existing per-CRL parsing-log list.
• One connection per HTTPS check. Certificate info is captured without opening a second full request per URL.
• Parser isolated. The 900-line ASN.1 CRL parser lives in its own file and runs in a background isolate via compute(), cleanly separated from networking and UI.
• Bug fixes. Corrected CrlValidityInfo deserialization (it previously dropped timeUntilInvalid and parsingLogs) and fixed ping timing on the HTTPS fallback port.
• Dark mode, centralized theming, shared formatters, and real unit tests.

Features

• URL HTTP/HTTPS availability checks with response-time measurement
• DNS resolution with on-demand TCP "ping" of resolved IPs
• CRL download + ASN.1 parsing: issuer/CA, CRL number, revoked count, this/next update
• Certificate expiry warnings (within 30 days) and CRL expiry warnings (within 1 hour)
• Live, per-item status updates across three tabs
• Configurable targets with persistence; reset to defaults

Requirements

• Flutter SDK 3.24+ (Dart 3.5+)
• Android: min SDK 21, target SDK 34
• iOS: 12.0+

Getting started

flutter pub get
flutter run

Run the tests:

flutter test

Build:

flutter build apk --release      # Android
flutter build ios --release      # iOS (requires Xcode + signing)

Project structure

lib/
├── main.dart                       # Entry point, nav shell, theming
├── models/
│   └── monitor_status.dart         # Data models (+ equality, fixed JSON)
├── services/
│   ├── monitor_controller.dart     # Orchestration & state (ChangeNotifier)
│   ├── url_monitor.dart            # HTTP/HTTPS + certificate checks
│   ├── dns_resolver.dart           # DNS resolution
│   ├── ping_service.dart           # TCP reachability
│   ├── crl_verifier.dart           # CRL fetch + validity assembly
│   ├── crl_parser.dart             # ASN.1 parsing (isolate, no UI deps)
│   └── configuration_manager.dart  # Persisted settings (batched load)
├── screens/
│   ├── monitor_screen.dart
│   ├── detail_screen.dart
│   └── settings_screen.dart
├── widgets/
│   └── monitor_item_card.dart      # Reusable status card
├── theme/app_theme.dart
└── utils/                          # config, logging, formatters

Default monitoring targets

The default URLs, DNS hosts, and CRL URLs match the original (XTec AuthentX / xpki endpoints) and can be changed in Settings.

Security notes

For monitoring purposes the app accepts all TLS certificates (including self-signed) and permits cleartext HTTP (needed for HTTP CRL distribution points). All checks are read-only.

License

MIT — see LICENSE.