mime2extension

A Flutter package for converting between MIME types and file extensions with wildcard support.

Features

• 🔄 Bidirectional conversion between MIME types and file extensions
• 🌟 Wildcard support for querying all extensions of a type (e.g., application/*)
• 📦 Comprehensive database with thousands of MIME type mappings
• 🎯 Type-safe with proper null handling
• ✅ Well-tested with comprehensive unit tests
• 🚀 Zero dependencies (except Flutter SDK)

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  mime2extension: ^0.0.1

Then run:

flutter pub get

Usage

Import the package

import 'package:mime2extension/mime2extension.dart';

Convert extension to MIME type

// Get MIME type for a known extension
String? mimeType = extension2Mime('pdf');
print(mimeType); // Output: application/pdf

// Handle unknown extensions
String? unknown = extension2Mime('xyz123');
print(unknown); // Output: null

Convert MIME type to extensions

// Get extensions for a specific MIME type
List<String> pdfExts = mime2Extension(['application/pdf']);
print(pdfExts); // Output: [pdf]

// Get extensions for an image type
List<String> pngExts = mime2Extension(['image/png']);
print(pngExts); // Output: [png]

Use wildcards to get all extensions of a category

// Get ALL application extensions
List<String> appExts = mime2Extension(['application/*']);
print(appExts.length); // Output: 836 extensions
print(appExts.take(5)); // Output: [ez, appinstaller, aw, appx, appxbundle]

// Get ALL image extensions
List<String> imageExts = mime2Extension(['image/*']);
print(imageExts); // Output: [png, jpg, jpeg, gif, bmp, ...]

// Get ALL audio extensions
List<String> audioExts = mime2Extension(['audio/*']);
print(audioExts); // Output: [mp3, wav, ogg, ...]

Combine multiple MIME types

// Mix exact MIME types and wildcards
List<String> combined = mime2Extension([
  'application/pdf',
  'image/*',
  'audio/mp3'
]);
// Returns: all image extensions + pdf + mp3

API Reference

extension2Mime(String extension)

Converts a file extension to its corresponding MIME type.

Parameters:

• extension (String): The file extension without the dot (e.g., 'png', 'pdf')

Returns:

• String?: The MIME type, or null if not found

Example:

extension2Mime('png');  // Returns: 'image/png'
extension2Mime('pdf');  // Returns: 'application/pdf'
extension2Mime('xyz');  // Returns: null

mime2Extension(List<String> mimeTypes)

Converts MIME types to their corresponding file extensions.

Parameters:

• mimeTypes (List

Returns:

• List<String>: List of unique file extensions

Example:

mime2Extension(['image/png']);              // Returns: ['png']
mime2Extension(['application/*']);          // Returns: all application extensions
mime2Extension(['image/*', 'audio/mp3']);   // Returns: all image extensions + mp3

Wildcard Patterns

The package supports wildcard patterns in the format type/*:

• application/* - All application MIME types (836 extensions)
• image/* - All image MIME types
• audio/* - All audio MIME types
• video/* - All video MIME types
• text/* - All text MIME types
• And more...

Examples

Check if a file is an image

bool isImageExtension(String ext) {
  final mimeType = extension2Mime(ext);
  return mimeType?.startsWith('image/') ?? false;
}

print(isImageExtension('png'));  // true
print(isImageExtension('pdf'));  // false

Get all supported document extensions

List<String> documentExts = mime2Extension([
  'application/pdf',
  'application/msword',
  'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
  'application/vnd.ms-excel',
  'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
]);
print(documentExts); // [pdf, doc, docx, xls, xlsx]

Filter files by MIME type category

List<String> getAllowedExtensions() {
  return mime2Extension([
    'image/*',    // All images
    'video/*',    // All videos
    'audio/*',    // All audio
  ]);
}

Database

The package includes a comprehensive database of MIME types sourced from:

• IANA Media Types
• Apache mime.types
• nginx mime.types

Testing

The package includes comprehensive unit tests. To run them:

flutter test

All 14 tests cover:

• Extension to MIME conversion
• MIME to extension conversion
• Wildcard pattern matching
• Edge cases and error handling
• Integration tests

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Changelog

See CHANGELOG.md for a list of changes.

Support

If you find this package helpful, please give it a ⭐ on GitHub!

For issues, questions, or suggestions, please open an issue.