Flutter OSS Manager

A powerful command-line interface (CLI) to streamline open-source license management in your Flutter projects. It scans all dependencies, identifies their licenses with high accuracy, and generates a single Dart file to easily display license information within your app.

This tool simplifies compliance with open-source licensing requirements, saving you time and effort.

Key Features

• Automated CLI Tool: A robust CLI for scanning dependencies and generating a oss_licenses.dart file.
• Comprehensive Dependency Scanning: Scans pubspec.yaml and pubspec.lock to identify all direct and transitive Dart/Flutter dependencies.
• Accurate License Discovery: Automatically finds and reads standard license files (LICENSE, COPYING, etc.) from package directories in the Pub cache.
• Flutter SDK License Handling: Correctly identifies and includes licenses for Flutter SDK packages (e.g., flutter, flutter_test).
• Advanced Two-Tier License Detection:
  • Tier 1: Heuristic Matching: Uses a sophisticated system of regular expressions, unique keywords, and exclusion rules for high-confidence, precise license identification.
  • Tier 2: Similarity-Based Fallback: If heuristic matching is inconclusive, it falls back to Jaccard similarity analysis against a comprehensive database of license templates.
• Broad License Support: Detects a wide range of open-source licenses, including:
  • MIT
  • Apache-2.0
  • BSD (2-Clause, 3-Clause, 4-Clause)
  • ISC
  • GPL (v2, v3)
  • LGPL (v2.1, v3)
  • MPL-2.0
• Clean Dart File Generation: Creates a well-structured oss_licenses.dart file with a list of OssLicense objects, containing:
  • name: Package name
  • version: Package version
  • licenseText: The full text of the license.
  • licenseSummary: A concise summary of the license type (e.g., "MIT", "Apache-2.0").
  • repositoryUrl: Link to the package's repository (if available).
  • description: The package's description from pubspec.yaml.

Installation

To use the CLI, add flutter_oss_manager as a dev_dependency in your pubspec.yaml:

dev_dependencies:
  flutter_oss_manager: ^1.0.0 # Replace with the latest version

Then, install it by running:

flutter pub get

Usage

Scanning Project Dependencies

The primary command is scan. Navigate to your project's root directory and run:

dart run flutter_oss_manager scan

This command will:

1. Scan your pubspec.lock file.
2. Find the license for each dependency.
3. Generate a summary and the full license text.
4. Create the lib/oss_licenses.dart file in your project.

To specify a different output location, use the --output (or -o) option:

dart run flutter_oss_manager scan --output path/to/your/licenses.dart

Generating a License for a Single File

The generate command is useful for creating a license object from a single license file (e.g., your own project's LICENSE file).

dart run flutter_oss_manager generate --license-file path/to/your/LICENSE --output lib/my_project_license.dart

Integrating into Your Flutter App

After generating oss_licenses.dart, you can import and use it to create a license page in your app. Here is a simple example:

// lib/main.dart
import 'package:flutter/material.dart';
import 'package:your_project_name/oss_licenses.dart'; // Adjust the import path if needed

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Open Source Licenses',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const LicenseListPage(),
    );
  }
}

class LicenseListPage extends StatelessWidget {
  const LicenseListPage({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Open Source Licenses'),
      ),
      body: ListView.builder(
        itemCount: ossLicenses.length,
        itemBuilder: (context, index) {
          final license = ossLicenses[index];
          return Card(
            margin: const EdgeInsets.all(8.0),
            child: ExpansionTile(
              title: Text('${license.name} v${license.version}'),
              subtitle: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(license.licenseSummary),
                  if (license.description != null) Padding(
                    padding: const EdgeInsets.only(top: 4.0),
                    child: Text(license.description!, style: Theme.of(context).textTheme.bodySmall),
                  ),
                  if (license.repositoryUrl != null) Padding(
                    padding: const EdgeInsets.only(top: 4.0),
                    child: Text(license.repositoryUrl!, style: Theme.of(context).textTheme.bodySmall),
                  ),
                ],
              ),
              children: [
                Padding(
                  padding: const EdgeInsets.all(16.0),
                  child: Text(license.licenseText),
                ),
              ],
            ),
          );
        },
      ),
    );
  }
}

License Detection Accuracy

This package employs a sophisticated two-tier detection system to ensure high accuracy:

1. Heuristic Pattern Matching (Primary): Utilizes a combination of regular expressions and unique keywords tailored to each license type. This method provides high-confidence detection for standard, well-formed licenses.
2. Similarity-Based Matching (Fallback): If the heuristic approach does not yield a confident result, the tool falls back to a Jaccard similarity comparison. It tokenizes the license text and compares it against a database of known license templates.

This dual approach ensures both speed and accuracy, providing robust identification even for licenses with minor variations.

Known Limitations

• Native Dependencies: This tool currently focuses on Dart/Flutter dependencies defined in pubspec.yaml. It does not scan licenses for native dependencies from Gradle (Android) or CocoaPods (iOS).
• Custom License Formats: While the detection system is robust, heavily modified or non-standard license files may not be identified correctly and might require manual verification.

Contributing

Contributions are welcome! If you find a bug or have a feature request, please open an issue. If you want to contribute code, please feel free to submit a pull request.

License

This package is licensed under the MIT License.