---

Welcome to the .NET nanoFramework MessagePack repository

This repository contains the MessagePack library for the .NET nanoFramework. It provides high-performance serialization and deserialization with the smallest possible payload, MessagePack is an object serialization specification like JSON.

Build status

Component	Build Status	NuGet Package
nanoFramework.MessagePack

nanoFramework.MessagePack

MessagePack is a simple, lightweight serialization library, inspired by MsgPack.Light, that can be used in .NETnanoFramework solutions.

Usage

Serialization to byte array

var value = new TestClass();
var bytes = MessagePackSerializer.Serialize(value);

Deserialization

var result = (TestClass)MessagePackSerializer.Deserialize(typeof(TestClass), bytes);

Your type serialization/deserialization

If you want to work with your own types, first thing you need to add is a type converter. Although the library provides almost complete coverage of the serialization/deserialization of any objects, there are certain cases where it is difficult to do without a custom converter.

The general principle of implementing a custom converter

1. In the code of your project, you need to create a converter class that inherits the IConverter interface and implement the Read and Write interface methods:

        public class SimpleCustomConverter : IConverter
        {
            #nullable enable
            public void Write(object? value, [NotNull] IMessagePackWriter writer)
            {
                //TODO Your code is here
            }
    
            public object? Read([NotNull] IMessagePackReader reader)
            {
               var yourObject = new YourObject();
               //TODO Your code is here
               return yourObject;
            }
        }

2. Register your custom converter in the context of serialization:

         public class Program
         {
             public static void Main()
             {
                   var simpleCustomConverter = new SimpleCustomConverter();
                   ConverterContext.Add(typeof(YourObject), simpleCustomConverter);
             }
         }

After completing these steps, the serialization/deserialization of the object for which your converter is added will occur in the methods of the custom converter.

A few examples of the implementation of custom converters

1. Case with enumeration elements as strings:

       namespace samples
       {
           public enum FieldType
           {
               _ = -1,
               Str,
               Num,
               Any
           }
   
           public class FieldTypeConverter : IConverter
           {
               internal FieldType Read(IMessagePackReader reader)
               {
                   var stringConverter = ConverterContext.GetConverter(typeof(string));
       
                   var enumString = (string)stringConverter.Read(reader);
       
                   return enumString switch
                   {
                       "Str" => FieldType.Str,
                       "Num" => FieldType.Num,
                       "*" => FieldType.Any,
                       _ => throw new Exception($"Unexpected enum {typeof(FieldType)} underlying type: {enumString}"),
                   };
               }
       
               internal void Write(FieldType value, [NotNull] IMessagePackWriter writer)
               {
                   var stringConverter = ConverterContext.GetConverter(typeof(string));
       
                   switch (value)
                   {
                       case FieldType.Str:
                           stringConverter.Write("Str", writer);
                           break;
                       case FieldType.Num:
                           stringConverter.Write("Num", writer);
                           break;
                       case FieldType.Any:
                           stringConverter.Write("*", writer);
                           break;
                       default:
                           throw new Exception($"Enum {value.GetType()} value: {value} expected");
                   }
               }
       
       #nullable enable
               object? IConverter.Read([NotNull] IMessagePackReader reader)
               {
                   return Read(reader);
               }
       
               public void Write(object? value, [NotNull] IMessagePackWriter writer)
               {
                   Write((FieldType)value!, writer);
               }
           }
       }

2. Case compression or concealment of transmitted strings between sender and recipient if sender and recipient share the same vocabulary of words:

       namespace samples
       {
           public static class SharedWordDictionary
           {
               static SharedWordDictionary()
               {
                   WordDictionary = new ArrayList
                   {
                       "MessagePak",
                       "Hello",
                       "at",
                       "nanoFramework!",
                       " "
                   };
               }
       
               public static ArrayList WordDictionary { get; }
           }
       
           public class SecureMessage
           {
               public SecureMessage(string message)
               {
                   Message = message;
               }
       
               public string Message { get; private set; }
           }
       
           public class SecureMessageConverter : IConverter
           {
               public SecureMessage Read([NotNull] IMessagePackReader reader)
               {
                   StringBuilder sb = new();
                   var length = reader.ReadArrayLength();
       
                   for(int i = 0; i < length; i++)
                   {
                       sb.Append(SharedWordDictionary.WordDictionary[i]);
                       sb.Append(' ');
                   }
                   if (sb.Length > 0)
                       sb.Remove(sb.Length - 1, 1);
       
                   return new SecureMessage(sb.ToString());
               }
       
               public void Write(SecureMessage value, [NotNull] IMessagePackWriter writer)
               {
                   var messageWords = value.Message.Split(' ');
       
                   uint length = BitConverter.ToUInt32(BitConverter.GetBytes(messageWords.Length), 0);
                   writer.WriteArrayHeader(length);
       
                   var intConverter = ConverterContext.GetConverter(typeof(int));
       
                   foreach (var word in messageWords)
                   {
                       intConverter.Write(SharedWordDictionary.WordDictionary.IndexOf(word), writer);
                   }
               }
       
       #nullable enable
               object? IConverter.Read([NotNull] IMessagePackReader reader)
               {
                   return Read(reader);
               }
       
               public void Write(object? value, [NotNull] IMessagePackWriter writer)
               {
                   Write((SecureMessage)value!, writer);
               }
           }
       
           public class Program
           {
               public static void Main()
               {
                   var secureMessageConverter = new SecureMessageConverter();
                   ConverterContext.Add(typeof(SecureMessage), secureMessageConverter);
       
                   var secureMessage = new SecureMessage("Hello MessagePack at nanoFramework!");
       
                   //At sender
                   var buffer = MessagePackSerializer.Serialize(secureMessage);
                   Debug.WriteLine($"The message:\n{secureMessage.Message}\nbeing sent has been serialized into {buffer.Length} bytes.");
                   //and sent to recipient
                   //
                   //..........................
                   Debug.WriteLine("=============================================");
       
                   //At recipient, after receiving the byte array
                   Debug.WriteLine($"Received {buffer.Length} bytes");
       
                   var recipientSecureMessage = (SecureMessage)MessagePackSerializer.Deserialize(typeof(SecureMessage), buffer)!;
       
                   Debug.WriteLine($"Message received:\n{recipientSecureMessage.Message}");
               }
           }
       }

Acknowledgements

The initial version of the MessagePack library was coded by Spirin Dmitriy, who has kindly handed over the library to the .NET nanoFramework project.

Feedback and documentation

For documentation, providing feedback, issues, and finding out how to contribute, please refer to the Home repo.

Join our Discord community here.

Credits

The list of contributors to this project can be found at CONTRIBUTORS.

License

The nanoFramework WebServer library is licensed under the MIT license.

Code of Conduct

This project has adopted the code of conduct defined by the Contributor Covenant to clarify expected behaviour in our community. For more information see the .NET Foundation Code of Conduct.

.NET Foundation

This project is supported by the .NET Foundation.