Axon

HTTP request logging middleware for the Dart server ecosystem.
Inspired by Morgan and built for Dart 3.

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Packages

Package	Description	Version
axon_core	Zero-dependency token engine, format compiler, serializers
axon_shelf	Shelf middleware adapter
axon_dart_frog	Dart Frog middleware adapter

Planned: axon_dio

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Quick start

dart pub add axon_shelf

import 'package:axon_shelf/axon_shelf.dart';
import 'package:shelf/shelf.dart';
import 'package:shelf/shelf_io.dart' as io;

void main() async {
  final handler = Pipeline()
      .addMiddleware(axonShelf())
      .addHandler((req) => Response.ok('hello'));

  await io.serve(handler, 'localhost', 8080);
}

Output:

GET / 200 3 ms
POST /api/users 201 12 ms
GET /api/users/42 404 1 ms

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Why Axon over Morgan?

Feature	Morgan (Node.js)	Axon (Dart)
Format strings	✅	✅
Predefined formats	✅	✅
Custom tokens	✅	✅
JSON output	❌ (manual workaround)	✅ Native
Numeric types in JSON	❌	✅ int/double preserved
Header masking	❌	✅ MaskingRules
Type safety	❌ (JavaScript)	✅ Dart 3 sealed classes
Fail-fast on bad format	❌	✅ FormatCompilationError
Auth-agnostic :remote-user	❌	✅ UserExtractor
TTY color auto-detect	❌	✅ dart:io detection

Monorepo

This repository is managed with Melos.

dart pub global activate melos
melos bootstrap    # install all dependencies
melos test         # run all tests
melos analyze      # dart analyze across packages
melos format       # dart format across packages
melos publish:dry  # dry-run publish check

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Contributing

Contributions are welcome. Please open an issue before submitting a PR for non-trivial changes.

• Follow Conventional Commits: Melos uses them for versioning.
• Run melos analyze and melos format:check before pushing.
• Add tests for any new token or serializer.
• Open an issue before submitting a PR for non-trivial changes

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License

MIT — see LICENSE.