pro_mpack

pro_mpack is a Dart library for serializing and deserializing data using the MessagePack format. It supports custom extension types and efficient binary encoding, making it ideal for applications that require compact and fast data interchange.

Features

• Serialize and deserialize Dart objects to and from MessagePack format.
• Support for custom extension types.
• Efficient binary encoding for various data types.
• Full support for MessagePack's type system, including integers, strings, arrays, maps, and more.

Installation

Add pro_mpack to your pubspec.yaml file:

dependencies:
  pro_mpack: ^1.0.1

Then run pub get to install the package.

Usage

Basic Serialization and Deserialization

import 'package:pro_mpack/pro_mpack.dart';

// Serialize an object
final serializedData = serialize({'key': 'value'});

// Deserialize the data back to an object
final deserializedData = deserialize(serializedData);

print(deserializedData); // Output: {key: value}

Custom Extension Types

To handle custom extension types, use mixin the ExtEncoder and ExtDecoder.

import 'dart:typed_data';

import 'package:pro_binary/pro_binary.dart';
import 'package:pro_mpack/pro_mpack.dart';

enum TimeStampFormat {
  ts32,
  ts64,
  ts96;

  static TimeStampFormat fromLength(int length) {
    switch (length) {
      case 4:
        return ts32;
      case 8:
        return ts64;
      case 12:
        return ts96;
      default:
        throw Exception('Invalid timestamp length');
    }
  }
}

/// Custom extension encoder for serializing DateTime objects.
class CustomTypesExtEncoder with ExtEncoder {
  CustomTypesExtEncoder({required this.timeStampFormat});

  /// The format of the timestamp.
  final TimeStampFormat timeStampFormat;

  @override
  int? extTypeForObject(Object? object) {
    if (object is DateTime) {
      return -1;
    }

    throw Exception('Unknown object type');
  }

  @override
  Uint8List encodeObject(Object? object) {
    if (object is DateTime) {
      final writer = BinaryWriter();

      switch (timeStampFormat) {
        case TimeStampFormat.ts32:
          final seconds = object.millisecondsSinceEpoch ~/ 1000;
          writer.writeUint32(seconds);
        case TimeStampFormat.ts64:
          final seconds = object.millisecondsSinceEpoch ~/ 1000;
          final nanoSeconds = (object.microsecondsSinceEpoch % 1000000) * 1000;
          writer.writeUint32(nanoSeconds);
          writer.writeUint32(seconds);
        case TimeStampFormat.ts96:
          final seconds = object.millisecondsSinceEpoch ~/ 1000;
          final nanoSeconds = (object.microsecondsSinceEpoch % 1000000) * 1000;
          writer.writeUint32(nanoSeconds);
          writer.writeInt64(seconds);
      }

      return writer.takeBytes();
    }

    throw Exception('Unknown object type');
  }
}

/// Custom extension decoder for deserializing DateTime objects.
class CustomTypesExtDecoder implements ExtDecoder {
  @override
  Object? decodeObject(int extType, Uint8List data) {
    if (extType == -1) {
      final type = TimeStampFormat.fromLength(data.length);
      final reader = BinaryReader(data);
      switch (type) {
        // Timestamp 32: stores the number of seconds that have elapsed since
        // 1970-01-01 00:00:00 UTC in a 32-bit unsigned integer.
        case TimeStampFormat.ts32:
          final seconds = reader.readUint32();
          return DateTime.fromMillisecondsSinceEpoch(
            seconds * 1000,
            isUtc: true,
          );
        // Timestamp 64: stores the number of seconds and nanoseconds that have
        // elapsed since 1970-01-01 00:00:00 UTC in 32-bit unsigned integers.
        case TimeStampFormat.ts64:
          final nanoSeconds = reader.readUint32();
          final seconds = reader.readUint32();
          return DateTime.fromMillisecondsSinceEpoch(
            seconds * 1000,
            isUtc: true,
          ).add(Duration(microseconds: nanoSeconds ~/ 1000));
        // Timestamp 96: stores the number of seconds and nanoseconds that have
        // elapsed since 1970-01-01 00:00:00 UTC in a 64-bit signed integer and
        // a 32-bit unsigned integer.
        case TimeStampFormat.ts96:
          final nanoSeconds = reader.readUint32();
          final seconds = reader.readInt64();
          return DateTime.fromMillisecondsSinceEpoch(
            seconds * 1000,
            isUtc: true,
          ).add(Duration(microseconds: nanoSeconds ~/ 1000));
      }
    }
    throw UnimplementedError();
  }
}

void main() {
  // Serialize with custom extension
  final date = DateTime.utc(2021, 1, 1, 12, 32, 5, 880, 999);
  final userData = serialize(
    {
      'id': 1,
      'name': 'John Doe',
      'created': date,
      'updated': date.add(const Duration(days: 1)),
    },
    extEncoder: CustomTypesExtEncoder(
      timeStampFormat: TimeStampFormat.ts64,
    ),
  );

  // Deserialize with custom extension
  final deserializedData = deserialize(
    userData,
    extDecoder: CustomTypesExtDecoder(),
  );

  print(deserializedData);
  // Output:
  // {
  //  id: 1,
  //  name: John Doe,
  //  created: 2021-01-01 12:32:05.880999Z,
  //  updated: 2021-01-02 12:32:05.880999Z
  //}
}

Running Tests

To run the tests for pro_mpack, use the following command:

dart pub run test

Contributions

Contributions are welcome! Please open an issue or submit a pull request on GitHub.

License

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