How to serialize a custom class?

Unity Engine
,
1

My class is all the data needed for each player. It has lists, built in types, and a few methods, but those methods don’t need to be transmitted and can be removed if it’ll make implementation easier. It also has a list of a different class inside it, which is used for a major component of board state. The docs are not clear whatsoever, so, how would I go about serializing this data? I can provide the code if needed but the question looks general enough to me for no specific code to be necessary. I understand I can send each piece individually, and that’s my backup if I can’t just do this, but I would greatly prefer being able to send everything for the purposes of scalability.

2

The minimal setup to get any class serialized as a serializable field (either public as in this case or attributed with [SerializeField]) is to simply attribute the class as [Serializable]:

[System.Serializable]
public class MyData
{
    public int exampleValue;
}

public class MyBehaviour : MonoBehaviour
{
    public MyData data;
}

You can also use JsonUtility to serialize the fields of MyData manually to a json string/file.
And if you want to take this further, Unity has a com.unity.serialization package that allows you to serialize to binary in a fast and convenient way.

3

Sorry, I completely failed on providing a basic part of my question. How do I serialize it for the unity network? I need to be able to transmit it using a client rpc.

4

By implementing INetworkSerializable. See examples in the manual: INetworkSerializable | Unity Multiplayer Networking

5

Those examples are very clear how to implement a struct. I looked at them quite a bit before asking. I don’t know how to make it work with class. Ref isn’t allowed for class properties.

6

To serialise a class field within a class you can create your classes like this:

public class SomeData : INetworkSerializable
{
    int someValue;
    MoreData moreData;

    public SomeData()
    {
    }

    public SomeData(int someValue, int anotherValue)
    {
        this.someValue = someValue;
        moreData = new MoreData(anotherValue);
    }

    public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
    {
        serializer.SerializeValue(ref someValue);
        serializer.SerializeNetworkSerializable(ref moreData);
    }

    public override string ToString()
    {
        return someValue.ToString() + " " + moreData;
    }
}

public class MoreData : INetworkSerializable
{
    int dataValue;

    public MoreData()
    {
    }

    public MoreData(int dataValue)
    {
        this.dataValue = dataValue;
    }

    public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
    {
        serializer.SerializeValue(ref dataValue);
    }

    public override string ToString()
    {
        return dataValue.ToString();
    }
}

You might want to share your code if you’re doing something more complicated.

7

One last problem, how do I serialize an array of a custom type? I get the error “The type ‘serverScript.spell[ ]’ must be a non-nullable value type, along with all fields at any level of nesting, in order to use it as parameter ‘T’ in the generic type or method ‘BufferSerializer.SerializeValue(ref T, FastBufferWriter.ForPrimitives)’”

8

Something along these lines will work:

public class SomeData : INetworkSerializable
{
    int someValue;
    MoreData moreData;
    MoreData[] moreDataArray;

    public SomeData()
    {
    }

    public SomeData(int someValue, int anotherValue)
    {
        this.someValue = someValue;
        moreData = new MoreData(anotherValue);

        moreDataArray = new MoreData[]
        {
            new MoreData(1),
            new MoreData(2),
            new MoreData(3),
            new MoreData(4),
            new MoreData(5)
    };
    }

    public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
    {
        serializer.SerializeValue(ref someValue);
        serializer.SerializeNetworkSerializable(ref moreData);

        if(serializer.IsWriter)
        {
            FastBufferWriter writer = serializer.GetFastBufferWriter();

            writer.WriteValueSafe(moreDataArray.Length);

            foreach (var data in moreDataArray)
            {
                writer.WriteValueSafe(data);
            }
        }

        if (serializer.IsReader)
        {
            FastBufferReader reader = serializer.GetFastBufferReader();

            reader.ReadValueSafe(out int length);

            moreDataArray = new MoreData[length];

            for (int i = 0; i < length; i++)
            {
                reader.ReadValueSafe(out moreDataArray[i]);
            }
        }
    }

    public override string ToString()
    {
        StringBuilder stringBuilder = new StringBuilder("SomeData");
        stringBuilder.Append(" someValue ").Append(someValue);
        stringBuilder.Append(" moreData ").Append(moreData);

        foreach (var data in moreDataArray)
        {
            stringBuilder.Append(" arrayData ").Append(data);
        }

        return stringBuilder.ToString();
    }
}
9

Hi

Just wondering if you ever got the array of custom serialization working. As I am having this exact issue right now.

10

This is my current work on array serialization, which is quite similar to @cerestorm :

public struct CustomStruct : INetworkSerializable
{
    public int A;
    public int B;

    public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
    {
        serializer.SerializeValue(ref A);
        serializer.SerializeValue(ref B);
    }
}

public struct AnotherStruct : INetworkSerializable
{
    CustomStruct[] cArray;

    public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
    {
        int n = cArray != null ? cArray.Length : 0;
        serializer.SerializeValue(ref n);
        if (serializer.IsReader)
        {
            cArray = new CustomStruct[n];
        }
        for (int i = 0; i < n; i++)
        {
            // Serialize each item in the array
            serializer.SerializeValue(ref cArray[i]);
        }
    }
}

I believe you can directly loop through the array with the serializer.SerializeValue if you are %100 sure that is not null :smile:.

11

Oh, i have not touched any network related programming. Found out my issue was that unity doesn’t support serializing multi dimensional arrays. I ended up figuring out a workaround.