MessagePack for C#(.NET, .NET Core, Unity, Xamarin)

Extremely fast MessagePack serializer for C#, x10 faster than MsgPack-Cli and acquires best performance compared with all the other C# serializers. MessagePack for C# has built-in LZ4 compression which can achieve super fast and small binary size. Performance is always important! for Game, Distributed Computing, MicroServices, Store Data to Redis, etc.

MessagePack has compact binary size and full set of general purpose expression. Please see the comparison with JSON, protobuf, ZeroFormatter section. If you want to know why MessagePack C# is fastest, please see performance section.

Install

The library provides in NuGet except for Unity.

Standard library for .NET, .NET Core, Xamarin.

Install-Package MessagePack

Visual Studio Analyzer to help object definition

Install-Package MessagePackAnalyzer

Extension Packages(info is see extensions section).

Install-Package MessagePack.ImmutableCollection
Install-Package MessagePack.ReactiveProperty
Install-Package MessagePack.UnityShims
Install-Package MessagePack.AspNetCoreMvcFormatter

for Unity, download from releases page, providing .unitypackage. Unity IL2CPP or Xamarin AOT Environment, check the pre-code generation section.

Quick Start

Define class and mark as [MessagePackObject] and public members(property or field) mark [Key], call MessagePackSerializer.Serialize<T>/Deserialize<T>. ToJson helps dump binary.

// mark MessagePackObjectAttribute
[MessagePackObject]
public class MyClass
{
    // Key is serialization index, it is important for versioning.
    [Key(0)]
    public int Age { get; set; }

    [Key(1)]
    public string FirstName { get; set; }

    [Key(2)]
    public string LastName { get; set; }

    // public members and does not serialize target, mark IgnoreMemberttribute
	[IgnoreMember]
    public string FullName { get { return FirstName + LastName; } }
}

class Program
{
    static void Main(string[] args)
    {
        var mc = new MyClass
        {
            Age = 99,
            FirstName = "hoge",
            LastName = "huga",
        };

        // call Serialize/Deserialize, that's all.
        var bytes = MessagePackSerializer.Serialize(mc);
        var mc2 = MessagePackSerializer.Deserialize<MyClass>(bytes);

        // you can dump msgpack binary to human readable json.
        // In default, MeesagePack for C# reduce property name information.
        // [99,"hoge","huga"]
        var json = MessagePackSerializer.ToJson(bytes);
        Console.WriteLine(json);
    }
}

By default the attribute is required. Optionally it can be unnecessary, see Object Serialization section and Formatter Resolver section for details.

Analyzer

MessagePackAnalyzer helps object definition. Attributes, accessibility etc are detected and it becomes a compiler error.

If you want to allow a specific type (for example, when registering a custom type), put MessagePackAnalyzer.json at the project root and make the Build Action to AdditionalFiles.

This is a sample of the contents of MessagePackAnalyzer.json.

[ "MyNamespace.FooClass", "MyNameSpace.BarStruct" ]

Built-in support types

These types can serialize by default.

Primitives(int, string, etc...), Enum, Nullable<>, TimeSpan, DateTime, DateTimeOffset, Nil, Guid, Uri, Version, StringBuilder, BitArray, ArraySegment<>, BigInteger, Complext, Task, Array[], Array[,], Array[,,], Array[,,,], KeyValuePair<,>, Tuple<,...>, ValueTuple<,...>, List<>, LinkedList<>, Queue<>, Stack<>, HashSet<>, ReadOnlyCollection<>, IList<>, ICollection<>, IEnumerable<>, Dictionary<,>, IDictionary<,>, SortedDictionary<,>, SortedList<,>, ILookup<,>, IGrouping<,>, ObservableCollection<>, ReadOnlyOnservableCollection<>, IReadOnlyList<>, IReadOnlyCollection<>, ISet<>, ConcurrentBag<>, ConcurrentQueue<>, ConcurrentStack<>, ReadOnlyDictionary<,>, IReadOnlyDictionary<,>, ConcurrentDictionary<,>, Lazy<>, Task<> and custom inherited ICollection<> or IDictionary<,> with paramterless constructor.

You can add custom type support and has some official extension package. for ImmutableCollections(ImmutableList<>, etc), for ReactiveProperty and for Unity(Vector3, Quaternion, etc...). Please see extensions section.

MessagePack.Nil is built-in null/void/unit representation type of MessagePack for C#.

Object Serialization

MessagePack for C# can serialze your own public Class or Struct. Serialization target must marks [MessagePackObject] and [Key]. Key type can choose int or string. If key type is int, serialized format is used array. If key type is string, serialized format is used map. If you define [MessagePackObject(keyAsPropertyName: true)], does not require KeyAttribute.

[MessagePackObject]
public class Sample1
{
    [Key(0)]
    public int Foo { get; set; }
    [Key(1)]
    public int Bar { get; set; }
}

[MessagePackObject]
public class Sample2
{
    [Key("foo")]
    public int Foo { get; set; }
    [Key("bar")]
    public int Bar { get; set; }
}

[MessagePackObject(keyAsPropertyName: true)]
public class Sample3
{
    // no needs KeyAttribute
    public int Foo { get; set; }

    // If ignore public member, you can use IgnoreMemberAttribute
    [IgnoreMember]
    public int Bar { get; set; }
}

// [10,20]
Console.WriteLine(MessagePackSerializer.ToJson(new Sample1 { Foo = 10, Bar = 20 }));

// {"foo":10,"bar":20}
Console.WriteLine(MessagePackSerializer.ToJson(new Sample2 { Foo = 10, Bar = 20 }));

// {"Foo":10}
Console.WriteLine(MessagePackSerializer.ToJson(new Sample3 { Foo = 10, Bar = 20 }));

All patterns serialization target are public instance member(field or property). If you want to avoid serialization target, you can add [IgnoreMember] to target member.

target class must be public, does not allows private, internal class.

Which should uses int key or string key? I recommend use int key because faster and compact than string key. But string key has key name information, it is useful for debugging.

MessagePackSerializer requests target must put attribute is for robustness. If class is grown, you need to be conscious of versioning. MessagePackSerializer uses default value if key does not exists. If uses int key, should be start from 0 and should be sequential. If unnecessary properties come out, please make a missing number. Reuse is bad. Also, if Int Key's jump number is too large, it affects binary size.

[MessagePackObject]
public class IntKeySample
{
    [Key(3)]
    public int A { get; set; }
    [Key(10)]
    public int B { get; set; }
}

// [null,null,null,0,null,null,null,null,null,null,0]
Console.WriteLine(MessagePackSerializer.ToJson(new IntKeySample()));

I want to use like JSON.NET! I don't want to put attribute! If you think that way, you can use a contractless resolver.

public class ContractlessSample
{
    public int MyProperty1 { get; set; }
    public int MyProperty2 { get; set; }
}

var data = new ContractlessSample { MyProperty1 = 99, MyProperty2 = 9999 };
var bin = MessagePackSerializer.Serialize(data, MessagePack.Resolvers.ContractlessStandardResolver.Instance);

// {"MyProperty1":99,"MyProperty2":9999}
Console.WriteLine(MessagePackSerializer.ToJson(bin));

ContractlessStandardResolver can serialize anonymous type.

Resolver is key customize point of MessagePack for C#. Details, please see extension point.

Serialize ImmutableObject(SerializationConstructor)

MessagePack for C# supports serialize immutable object. This struct can serialize naturally.

[MessagePackObject]
public struct Point
{
    [Key(0)]
    public readonly int X;
    [Key(1)]
    public readonly int Y;

    public Point(int x, int y)
    {
        this.X = x;
        this.Y = y;
    }
}

var data = new Point(99, 9999);
var bin = MessagePackSerializer.Serialize(data);

// [99,9999]
Console.WriteLine(MessagePackSerializer.ToJson(bin));

MessagePackSerializer choose constructor with the least argument and match index if key in integer or match name(ignore case) if key is string.

If can not match automatically, you can specify to use constructor manually by [SerializationConstructorAttribute].

[MessagePackObject]
public struct Point
{
    [Key(0)]
    public readonly int X;
    [Key(1)]
    public readonly int Y;

    // can't find matched constructor parameter, parameterType mismatch. type:Point parameterIndex:0 paramterType:ValueTuple`2
    public Point((int, int) p)
    {
        X = p.Item1;
        Y = p.Item2;
    }

    [SerializationConstructor]
    public Point(int x, int y)
    {
        this.X = x;
        this.Y = y;
    }
}

Serialization Callback

If object implements IMessagePackSerializationCallbackReceiver, received OnBeforeSerialize and OnAfterDeserialize on serilization process.

[MessagePackObject]
public class SampleCallback : IMessagePackSerializationCallbackReceiver
{
    [Key(0)]
    public int Key { get; set; }

    public void OnBeforeSerialize()
    {
        Console.WriteLine("OnBefore");
    }

    public void OnAfterDeserialize()
    {
        Console.WriteLine("OnAfter");
    }
}

Union

MessagePack for C# supports serialize interface. It is like XmlInclude or ProtoInclude. MessagePack for C# there called Union. UnionAttribute can only attach to interface. It requires discriminated integer key and sub-type.

// mark inheritance types
[MessagePack.Union(0, typeof(FooClass))]
[MessagePack.Union(1, typeof(BarClass))]
public interface IUnionSample
{
}

[MessagePackObject]
public class FooClass : IUnionSample
{
    [Key(0)]
    public int XYZ { get; set; }
}

[MessagePackObject]
public class BarClass : IUnionSample
{
    [Key(0)]
    public string OPQ { get; set; }
}

// ---

IUnionSample data = new FooClass() { XYZ = 999 };

// serialize interface.
var bin = MessagePackSerializer.Serialize(data);

// deserialize interface.
var reData = MessagePackSerializer.Deserialize<IUnionSample>(bin);

// use type-switch of C# 7.0
switch (reData)
{
    case FooClass x:
        Console.WriteLine(x.XYZ);
        break;
    case BarClass x:
        Console.WriteLine(x.OPQ);
        break;
    default:
        break;
}

C# 7.0 type-switch is best match for Union. Union is serialized to two-length array.

IUnionSample data = new BarClass { OPQ = "FooBar" };

var bin = MessagePackSerializer.Serialize(data);

// Union is serialized to two-length array, [key, object]
// [1,["FooBar"]]
Console.WriteLine(MessagePackSerializer.ToJson(bin));

Tips: If you want to pass single primitive like F#'s discriminated union. You can create single generic value and marked interface.

[Union(0, typeof(UnionValue<int>))]
[Union(1, typeof(UnionValue<float>))]
public interface IPrimitiveUnionA
{
}

[Union(0, typeof(UnionValue<string>))]
[Union(1, typeof(UnionValue<ValueTuple<int, int>>))]
public interface IPrimitiveUnionB
{
}

[MessagePackObject]
public class UnionValue<T> : IPrimitiveUnionA, IPrimitiveUnionB //, add your union types...
{
    [Key(0)]
    public T Value { get; private set; }

    [SerializationConstructor]
    public UnionValue(T value)
    {
        this.Value = value;
    }
}

// helper of typesafe create value..
public static class PrimitiveUnionA
{
    public static IPrimitiveUnionA Create(int value)
    {
        return new UnionValue<int>(value);
    }

    public static IPrimitiveUnionA Create(float value)
    {
        return new UnionValue<float>(value);
    }
}

// usage, create value and Serialize/Deserialize...

var a1 = PrimitiveUnionA.Create(100);
var a2 = PrimitiveUnionA.Create(100.423f);

Performance

Benchmarks comparing to other serializers run on Windows 10 Pro x64 Intel Core i7-6700K 4.00GHz, 32GB RAM. Benchmark code is here - and there version info, ZeroFormatter and FlatBuffers has infinitely fast deserializer so ignore deserialize performance.

MessagePack for C# uses many techniques for improve performance.

• Serializer uses only ref byte[] and int offset, don't use (Memory)Stream(call Stream api has overhead)
• High-level API uses internal memory pool, don't allocate working memory under 64K
• Don't create intermediate utility instance(XxxWriter/Reader, XxxContext, etc...)
• Avoid boxing all codes, all platforms(include Unity/IL2CPP)
• Getting cached generated formatter on static generic field(don't use dictinary-cache because dictionary lookup is overhead): see:Resolvers
• Heavyly tuned dynamic il code generation: see:DynamicObjectTypeBuilder
• Call PrimitiveAPI directly when il code generation knows target is primitive
• Reduce branch of variable length format when il code generation knows target(integer/string) range
• Don't use IEnumerable<T> abstraction on iterate collection, see:CollectionFormatterBase and inherited collection formatters
• Uses pre generated lookup table to reduce check messagepack type, see: MessagePackBinary

Before creating this library, I implemented a fast fast serializer with ZeroFormatter#Performance. And this is a further evolved implementation. MessagePack for C# is always fast, optimized for all types(primitive, small struct, large object, any collections).

LZ4 Compression

MessagePack is a fast and compact format but it is not compression. LZ4 is extremely fast compression algorithm, with MessagePack for C# can achive extremely fast perfrormance and extremely compact binary size!

MessagePack for C# has built-in LZ4 support. You can use LZ4MessagePackSerializer instead of MessagePackSerializer. Builtin support is special, I've created serialize-compression pipeline and special tuned for the pipeline so share the working memory, don't allocate, don't resize until finished.

Serialized binary is not simply compressed lz4 binary. Serialized binary is valid MessagePack binary used ext-format and custom typecode(99).

var array= Enumerable.Range(1, 100).Select(x => new MyClass { Age = 5, FirstName = "foo", LastName = "bar" }).ToArray();

// call LZ4MessagePackSerializer instead of MessagePackSerializer, api is completely same
var lz4Bytes = LZ4MessagePackSerializer.Serialize(array);
var mc2 = LZ4MessagePackSerializer.Deserialize<MyClass[]>(lz4Bytes);

// you can dump lz4 message pack
// [[5,"hoge","huga"],[5,"hoge","huga"],....]
var json = LZ4MessagePackSerializer.ToJson(lz4Bytes);
Console.WriteLine(json);

// lz4Bytes is valid MessagePack, it is using ext-format( [TypeCode:99, SourceLength|CompressedBinary] )
// [99,"0gAAA+vf3ABkkwWjZm9vo2JhcgoA////yVBvo2Jhcg=="]
var rawJson = MessagePackSerializer.ToJson(lz4Bytes);
Console.WriteLine(rawJson);

built-in LZ4 support uses primitive LZ4 API. The LZ4 API is more efficient if you know the size of original source length. Therefore, size is written on the top.

Compression speed is not always fast. Depending on the target binary, it may be short or longer. However, even at worst, it is about twice, but it is still often faster than other uncompressed serializers.

If target binary size under 64 bytes, LZ4MessagePackSerializer does not compress to optimize small size serialization.

Compare with protobuf, JSON, ZeroFormatter

protbuf-net is major, most used binary-format library on .NET. I love protobuf-net and respect that great work. But if uses protobuf-net for general-purpose serialization format, you may encounts annoying issue.

[ProtoContract]
public class Parent
{
    [ProtoMember(1)]
    public int Primitive { get; set; }
    [ProtoMember(2)]
    public Child Prop { get; set; }
    [ProtoMember(3)]
    public int[] Array { get; set; }
}

[ProtoContract]
public class Child
{
    [ProtoMember(1)]
    public int Number { get; set; }
}

using (var ms = new MemoryStream())
{
    // serialize null.
    ProtoBuf.Serializer.Serialize<Parent>(ms, null);

    ms.Position = 0;
    var result = ProtoBuf.Serializer.Deserialize<Parent>(ms);

    Console.WriteLine(result != null); // True, not null. but all property are zero formatted.
    Console.WriteLine(result.Primitive); // 0
    Console.WriteLine(result.Prop); // null
    Console.WriteLine(result.Array); // null
}

using (var ms = new MemoryStream())
{
    // serialize empty array.
    ProtoBuf.Serializer.Serialize<Parent>(ms, new Parent { Array = new int[0] });

    ms.Position = 0;
    var result = ProtoBuf.Serializer.Deserialize<Parent>(ms);

    Console.WriteLine(result.Array == null); // True, null!
}

protobuf(-net) can not handle null and empty collection correctly. Because protobuf has no null representation( this is the protobuf-net authors answer).

MessagePack specification can completely serialize C# type system. This is the reason to recommend MessagePack over protobuf.

Protocol Buffers has good IDL and gRPC, that is a much good point than MessagePack. If you want to use IDL, I recommend Google.Protobuf than MessagePack.

JSON is good general-purpose format. It is perfect, simple and enough spec. But it's text. Text can not avoid the overhead of UTF-8 conversion. Jil is wonderful, but can not exceed the difference in wire format specifications.

ZeroFormatter is similar as FlatBuffers but specialized to C#. It is special. Deserialization is infinitely fast but instead the binary size is large. And ZeroFormatter's caching algorithm requires additional memory.

Again, ZeroFormatter is special. When situation matches with ZeroFormatter, it demonstrates power of format. But for many common uses, MessagePack for C# would be better.

Extensions

MessagePack for C# has extension point and you can add external type's serialization support. There are official extension support.

Install-Package MessagePack.ImmutableCollection
Install-Package MessagePack.ReactiveProperty
Install-Package MessagePack.UnityShims
Install-Package MessagePack.AspNetCoreMvcFormatter

MessagePack.ImmutableCollection package add support for System.Collections.Immutable library. It adds ImmutableArray<>, ImmutableList<>, ImmutableDictionary<,>, ImmutableHashSet<>, ImmutableSortedDictionary<,>, ImmutableSortedSet<>, ImmutableQueue<>, ImmutableStack<>, IImmutableList<>, IImmutableDictionary<,>, IImmutableQueue<>, IImmutableSet<>, IImmutableStack<> serialization support.

MessagePack.ReactiveProperty package add support for ReactiveProperty library. It adds ReactiveProperty<>, IReactiveProperty<>, IReadOnlyReactiveProperty<>, ReactiveCollection<>, Unit serialization support. It is useful for save viewmodel state.

MessagePack.UnityShims package provides shim of Unity's standard struct(Vector2, Vector3, Vector4, Quaternion, Color, Bounds, Rect) and there formatter. It can enable to commnicate between server and Unity client.

After install, extension package must enable by configuration. Here is sample of enable all extension.

// set extensions to default resolver.
MessagePack.Resolvers.CompositeResolver.RegisterAndSetAsDefault(
    // enable extension packages first
    ImmutableCollectionResolver.Instance,
    ReactivePropertyResolver.Instance,
    MessagePack.Unity.Extension.UnityBlitResolver.Instance,
    MessagePack.Unity.UnityResolver.Instance,

    // finaly use standard(default) resolver
    StandardResolver.Instance);
);

Configuration details, see:Extension Point section.

MessagePack.AspNetCoreMvcFormatter is add-on of ASP.NET Core MVC's serialization to boostup performance. This is configuration sample.

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc().AddMvcOptions(option =>
    {
	    // ContractlessStandardResolver supports anonymous type, or use your custom composite resolver.
        option.OutputFormatters.Clear();
        option.OutputFormatters.Add(new MessagePackOutputFormatter(ContractlessStandardResolver.Instance));
        option.InputFormatters.Clear();
        option.InputFormatters.Add(new MessagePackInputFormatter(ContractlessStandardResolver.Instance));
    });
}

Author is creating other extension packages, too.

• MasterMemory - Embedded Readonly In-Memory Document Database
• MagicOnion - gRPC based HTTP/2 RPC Streaming Framework

You can make your own extension serializers, let's create them and share it!

High-Level API(MessagePackSerializer)

MessagePackSerializer is the entry point of MessagePack for C#. Its static methods are main API of MessagePack for C#.

API	Description
DefaultResolver	FormatterResolver that used resolver less overloads. If does not set it, used StandardResolver.
SetDefaultResolver	Set default resolver of MessagePackSerializer APIs.
Serialize<T>	Convert object to byte[] or write to stream. There has IFormatterResolver overload, used specified resolver.
SerializeUnsafe<T>	Same as Serialize<T> but return ArraySegement<byte>. The result of ArraySegment is contains internal buffer pool, it can not share across thread and can not hold, so use quickly.
Deserialize<T>	Convert byte[] or stream to object. There has IFormatterResolver overload, used specified resolver.
NonGeneric.*	NonGeneric APIs of Serialize/Deserialize. There accept type parameter at first argument. This API is bit slower than generic API but useful for framework integration such as ASP.NET formatter.
ToJson	Dump message-pack binary to JSON string. It is useful for debugging.

MessagePack for C# operates at the byte[] level, so byte[] API is faster than Stream API.

High-Level API uses memory pool internaly to avoid unnecessary memory allocation. If result size is under 64K, allocates GC memory only for the return bytes.

LZ4MessagePackSerializer has same api with MessagePackSerializer and DefaultResolver is shared. LZ4MessagePackSerializer has additional SerializeToBlock method.

Low-Level API(IMessagePackFormatter)

IMessagePackFormatter is serializer by each type. For example Int32Formatter : IMessagePackFormatter<Int32> represents Int32 MessagePack serializer.

public interface IMessagePackFormatter<T>
{
    int Serialize(ref byte[] bytes, int offset, T value, IFormatterResolver formatterResolver);
    T Deserialize(byte[] bytes, int offset, IFormatterResolver formatterResolver, out int readSize);
}

All api works on byte[] level, no use Stream, no use Writer/Reader so improve performance. Many builtin formatters exists under MessagePack.Formatters. You can get sub type serializer by formatterResolver.GetFormatter<T>. Here is sample of write own formatter.

// serialize fileinfo as string fullpath.
public class FileInfoFormatter<T> : IMessagePackFormatter<FileInfo>
{
    public int Serialize(ref byte[] bytes, int offset, FileInfo value, IFormatterResolver formatterResolver)
    {
        if (value == null)
        {
            return MessagePackBinary.WriteNil(ref bytes, offset);
        }

        return MessagePackBinary.WriteString(ref bytes, offset, value.FullName);
    }

    public FileInfo Deserialize(byte[] bytes, int offset, IFormatterResolver formatterResolver, out int readSize)
    {
        if (MessagePackBinary.IsNil(bytes, offset))
        {
            readSize = 1;
            return null;
        }

        var path = MessagePackBinary.ReadString(bytes, offset, out readSize);
        return new FileInfo(path);
    }
}

Created formatter needs to register to IFormatterResolver. Please see Extension Point section.

You can see many other samples from builtin formatters.

Primitive API(MessagePackBinary)

MessagePackBinary is most low-level API like Reader/Writer of other serializers. MessagePackBinary is static class because avoid create Reader/Writer allocation.

Method	Description
ReadNext	Skip MessagePackFormat binary block, returns read size.
ReadNextBlock	Skip MessagePackFormat binary block with sub structures(array/map), returns read size. This is useful for create deserializer.
Write/ReadMapHeader	Write/Read map format header(element length).
Write/ReadArrayHeader	Write/Read array format header(element length).
Write/Read***	*** is primitive type name(Int32, Single, String, etc...)
Write/ReadBytes	Write/Read byte[] to use bin format.
Write/ReadExtensionFormat	Write/Read ext format header(Length + TypeCode) and content byte[].
Write/ReadExtensionFormatHeader	Write/Read ext format, header(Length + TypeCode) only.
IsNil	Is TypeCode Nil?
IsMessagePackPrimitive	Is Type can become MessagePack Primitive(Sbyte, Byte, Int16, Int32, Int64, UInt16,UInt32, UInt64, Single, Double, Boolean, DateTime, Char, Byte[], String)?
GetMessagePackType	Return MessagePackType of target MessagePack bianary position.
EnsureCapacity	Resize if byte can not fill.
FastResize	Buffer.BlockCopy version of Array.Resize.
FastCloneWithResize	Same as FastResize but return copied byte[].

Read API returns deserialized primitive and read size. Write API returns write size and guranteed auto ensure ref byte[].

DateTime is serialized to new MessagePack extension spec proposal.

MessagePackType means msgpack spec of source types.

MessagePackCode means msgpack format of first byte. Its static class has ToMessagePackType and ToFormatName utility methods.

MessagePackRange means Min-Max fix range of msgpack format.

Extension Point(IFormatterResolver)

IFormatterResolver is storage of typed serializers. Serializer api accepts resolver and can customize serialization.

Resovler Name	Description
BuiltinResolver	Builtin primitive and standard classes resolver. It includes primitive(int, bool, string...) and there nullable, array and list. and some extra builtin types(Guid, Uri, BigInteger, etc...).
StandardResolver	Composited resolver . It resolves in the following order builtin -> dynamic enum -> dynamic generic -> dynamic union -> dynamic object. This is the default of MessagePackSerializer.
ContractlessStandardResolver	Composited StandardResolver -> DynamicContractlessObjectResolver. It enables contractless serialization.
CompositeResolver	Singleton helper of setup custom resolvers. You can use Register or RegisterAndSetAsDefault API.
DynamicEnumResolver	Resolver of enum and there nullable, serialize there underlying type. It uses dynamic code generation to avoid boxing and boostup performance serialize there name.
DynamicEnumAsStringResolver	Resolver of enum and there nullable. It uses reflection call for resolve nullable at first time.
DynamicGenericResolver	Resolver of generic type(Tuple<>, List<>, Dictionary<,>, Array, etc). It uses reflection call for resolve generic argument at first time.
DynamicUnionResolver	Resolver of interface marked by UnionAttribute. It uses dynamic code generation to create dynamic formatter.
DynamicObjectResolver	Resolver of class and struct maked by MessagePackObjectAttribute. It uses dynamic code generation to create dynamic formatter.
DynamicContractlessObjectResolver	Resolver of all classes and structs. It does not needs MessagePackObjectAttribute and serialized key as string(same as marked [MessagePackObject(true)]).

It is the only configuration point to assemble the resolver's priority. In most cases, it is sufficient to have one custom resolver globally. CompositeResolver will be its helper.

// use global-singleton CompositeResolver.
// This method initialize CompositeResolver and set to default MessagePackSerializer
CompositeResolver.RegisterAndSetAsDefault(
    // resolver custom types first
    ImmutableCollectionResolver.Instance,
    ReactivePropertyResolver.Instance,
    MessagePack.Unity.Extension.UnityBlitResolver.Instance,
    MessagePack.Unity.UnityResolver.Instance,

    // finaly use standard resolver
    StandardResolver.Instance);

Here is sample of use DynamicEnumAsStringResolver with DynamicContractlessObjectResolver(It is JSON.NET-like lightweight setting.)

// composite same as StandardResolver
CompositeResolver.RegisterAndSetAsDefault(
    MessagePack.Resolvers.BuiltinResolver.Instance,

    // replace enum resolver
    MessagePack.Resolvers.DynamicEnumAsStringResolver.Instance,

    MessagePack.Resolvers.DynamicGenericResolver.Instance,
    MessagePack.Resolvers.DynamicUnionResolver.Instance,
    MessagePack.Resolvers.DynamicObjectResolver.Instance,

    // final fallback(last priority)
    MessagePack.Resolvers.DynamicContractlessObjectResolver.Instance
);

If you want to write custom composite resolver, you can write like following.

public class CustomCompositeResolver : IFormatterResolver
{
    public static IFormatterResolver Instance = new CustomCompositeResolver();

    static readonly IFormatterResolver[] resolvers = new[]
    {
        // resolver custom types first
        ImmutableCollectionResolver.Instance,
        ReactivePropertyResolver.Instance,
        MessagePack.Unity.Extension.UnityBlitResolver.Instance,
        MessagePack.Unity.UnityResolver.Instance,
            
        // finaly use standard resolver
        StandardResolver.Instance
    };

    CustomCompositeResolver()
    {
    }

    public IMessagePackFormatter<T> GetFormatter<T>()
    {
        return FormatterCache<T>.formatter;
    }

    static class FormatterCache<T>
    {
        public static readonly IMessagePackFormatter<T> formatter;

        static FormatterCache()
        {
            foreach (var item in resolvers)
            {
                var f = item.GetFormatter<T>();
                if (f != null)
                {
                    formatter = f;
                    return;
                }
            }
        }
    }
}

IFormatterResolver can use per serialize/deserialize method.

MessagePackSerializer.Serialize(data, CustomCompositeResolver.Instance);

If you want to make your extension package, you need to make formatter and resolver. IMessagePackFormatter accepts IFormatterResolver on every request of serialize/deserialize. You can get child-type serialize on resolver.GetFormatterWithVerify<T>.

Here is sample of own resolver.

public class SampleCustomResolver : IFormatterResolver
{
    // Resolver should be singleton.
    public static IFormatterResolver Instance = new SampleCustomResolver();

    SampleCustomResolver()
    {
    }

    // GetFormatter<T>'s get cost should be minimized so use type cache.
    public IMessagePackFormatter<T> GetFormatter<T>()
    {
        return FormatterCache<T>.formatter;
    }

    static class FormatterCache<T>
    {
        public static readonly IMessagePackFormatter<T> formatter;

        // generic's static constructor should be minimized for reduce type generation size!
        // use outer helper method.
        static FormatterCache()
        {
            formatter = (IMessagePackFormatter<T>)SampleCustomResolverGetFormatterHelper.GetFormatter(typeof(T));
        }
    }
}

internal static class SampleCustomResolverGetFormatterHelper
{
    // If type is concrete type, use type-formatter map
    static readonly Dictionary<Type, object> formatterMap = new Dictionary<Type, object>()
    {
        {typeof(FileInfo), new FileInfoFormatter()}
        // add more your own custom serializers.
    };

    internal static object GetFormatter(Type t)
    {
        object formatter;
        if (formatterMap.TryGetValue(t, out formatter))
        {
            return formatter;
        }

        // If target type is generics, use MakeGenericType.
        if (t.IsGenericParameter && t.GetGenericTypeDefinition() == typeof(ValueTuple<,>))
        {
            return Activator.CreateInstance(typeof(ValueTupleFormatter<,>).MakeGenericType(t.GenericTypeArguments));
        }

        // If type can not get, must return null for fallback mecanism.
        return null;
    }
}

for Unity

You can install by package and includes source code. If build target as PC, you can use as is but if build target uses IL2CPP, you can not use Dynamic***Resolver so use pre-code generation. Please see pre-code generation section.

In Unity, MessagePackSerializer can serialize Vector2, Vector3, Quaternion, Color, Bounds, Rect and there nullable by built-in extension UnityResolver. It is included StandardResolver by default.

If you want to use LZ4 compression support, you must enables unsafe option and define additional symbols. At first, write -unsafe on smcs.rsp, gmcs.rsp etc. And define ENABLE_UNSAFE_MSGPACK symbol.

So you can use LZ4MessagePackSerialzer. And also additional unsafe extension of MessagePack for C# can use.

UnsafeBlitResolver is special resolver for extremely fast unsafe serialization/deserialization for struct array.

x20 faster Vector3[] serialization than native JsonUtility. If use UnsafeBlitResolver, serialize special format(ext:typecode 30~39) Vector2[], Vector3[], Quaternion[], Color[], Bounds[], Rect[]. If use UnityBlitWithPrimitiveArrayResolver, supports int[], float[], double[] too. This special feature is useful for serialize Mesh(many Vector3[]) or many transform position.

Here is sample of configuration.

Resolvers.CompositeResolver.RegisterAndSetAsDefault(
    MessagePack.Unity.UnityResolver.Instance,
    MessagePack.Unity.Extension.UnityBlitWithPrimitiveArrayResolver.Instance,

    // If PC, use StandardResolver
    // MessagePack.Resolvers.StandardResolver.Instance,

    // If IL2CPP, Builtin + GeneratedResolver.
    // MessagePack.Resolvers.BuiltinResolver.Instance,
);

MessagePack.UnityShims NuGet package is for .NET ServerSide serialization support to communicate with Unity. It includes shim of Vector3 etc and Safe/Unsafe serialization extension.

If you want to share class between Unity and Server, you can use SharedProject or Reference as Link or new MSBuild(VS2017)'s wildcard reference etc. Anyway you need to source-code level share.

Pre Code Generation(Unity/Xamarin Supports)

MessagePack for C# generates object formatter dynamically by ILGenerator. It is fast and transparently generated at run time. But it needs generate cost at first time and it does not work on AOT environment(Xamarin, Unity IL2CPP, etc.).

Note: If Unity's build target as PC, does not need code generation. It works well.

If you want to avoid generate cost or run on Xamarin or Unity, you need pre-code generation. mpc.exe(MessagePackCompiler) is code generator of MessagePack for C#. mpc is located in packages\MessagePack.*.*.*\tools\mpc.exe or includes for unity's package. mpc is using Roslyn so analyze source code.

mpc arguments help:
  -i, --input              [required]Input path of analyze csproj
  -o, --output             [required]Output file path
  -c, --conditionalsymbol  [optional, default=empty]conditional compiler symbol
  -r, --resolvername       [optional, default=GeneratedResolver]Set resolver name
  -n, --namespace          [optional, default=MessagePack]Set namespace root name
  -m, --usemapmode         [optional, default=false]Force use map mode serialization

// Simple Sample:
mpc.exe -i "..\src\Sandbox.Shared.csproj" -o "MessagePackGenerated.cs"

// Use force map simulate DynamicContractlessObjectResolver
mpc.exe -i "..\src\Sandbox.Shared.csproj" -o "MessagePackGenerated.cs" -m

If you create DLL by msbuild project, you can use Pre/Post build event.

<PropertyGroup>
    <PreBuildEvent>
        mpc.exe, here is useful for analyze/generate target is self project.
    </PreBuildEvent>
    <PostBuildEvent>
        mpc.exe, here is useful for analyze target is another project.
    </PostBuildEvent>
</PropertyGroup>

In default, mpc.exe generates resolver to MessagePack.Resolvers.GeneratedResolver and formatters generates to MessagePack.Formatters.***. And application launch, you need to set Resolver at first.

// CompositeResolver is singleton helper for use custom resolver.
// Ofcourse you can also make custom resolver.
MessagePack.Resolvers.CompositeResolver.RegisterAndSetAsDefault(
    // use generated resolver first, and combine many other generated/custom resolvers
    MessagePack.Resolvers.GeneratedResolver.Instance,

    // finally, use builtin resolver(don't use StandardResolver, it includes dynamic generation)
    MessagePack.Resolvers.BuiltinResolver.Instance
);

Note: mpc.exe is currently only run on Windows. It is .NET Core's Roslyn workspace API limitation and not supported yet. But I want to implements to all platforms...

RPC

MessagePack advocated MessagePack RPC, but formulation is stopped and it is not widely used. I've created gRPC based MessagePack HTTP/2 RPC streaming framework called MagicOnion. gRPC usually communicates with Protocol Buffers using IDL. But MagicOnion uses MessagePack for C# and does not needs IDL. If communicates C# to C#, schemaless(C# classes as schema) is better than IDL.

How to Build

Open MessagePack.sln on Visual Studio 2017.

Unity Project is using symbolic link. At first, run make_unity_symlink.bat so linked under Unity project. You can open src\MessagePack.UnityClient on Unity Editor.

Author Info

Yoshifumi Kawai(a.k.a. neuecc) is a software developer in Japan.
He is the Director/CTO at Grani, Inc.
Grani is a mobile game developer company in Japan and well known for using C#.
He is awarding Microsoft MVP for Visual C# since 2011.
He is known as the creator of UniRx(Reactive Extensions for Unity)

Blog: https://medium.com/@neuecc (English)
Blog: http://neue.cc/ (Japanese)
Twitter: https://twitter.com/neuecc (Japanese)

License

This library is under the MIT License.

lz4 compression support is using Milosz Krajewski's lz4net code with some modified.