PurrNet Conversion Tool

Switching networking solutions mid-project is painful. The PurrNet Conversion Tool takes care of the heavy lifting for you, converting your code, prefabs, and scenes from other networking systems to PurrNet.

It works through a recipe system where each source networking library has its own set of mappings and conversion logic. Right now, FishNet is supported out of the box, with more converters coming.

What it does

The tool handles three layers of conversion:

Code uses Roslyn to parse your C# files and apply type, namespace, method, property, and attribute mappings. It also handles trickier cases like merging FishNet's separate OnStartServer/OnStartClient into PurrNet's unified OnSpawned(bool asServer).

Prefabs finds networking components on your prefabs (like NetworkTransform, NetworkAnimator, NetworkObject) and swaps them out for the PurrNet equivalents, copying over relevant settings.

Scenes does the same for scene objects, including full NetworkManager conversion with transport setup and tick rate transfer.

Each step runs independently so you stay in control of the process.

Getting started

Install via PurrNet Package Manager

The easiest way. If you already have PurrNet installed, open the PurrNet Package Manager in Unity and install the Conversion Tool with a single click.

Install via git URL

You can also add the package through the Unity Package Manager using this git URL:

https://github.com/PurrNet/PurrNet-Conversion-Tool.git?path=/Assets/PurrNet-Conversion

Or add it directly to your Packages/manifest.json:

"dev.purrnet.conversion": "https://github.com/PurrNet/PurrNet-Conversion-Tool.git?path=/Assets/PurrNet-Conversion"

Requirements

You'll need PurrNet installed in your project. The source networking library you're converting from (e.g. FishNet) also needs to be present since the tool reads its components during prefab and scene conversion.

How to use it

Open the tool from Tools > PurrNet > Conversion Tool.

Select the networking system you're converting from in the dropdown
Set which folders to include for scripts, prefabs, and scenes (defaults to the entire Assets folder)
Run each conversion step in order: Convert Code, then Convert Prefabs, then Convert Scenes

The conversion log at the bottom of the window shows you what changed. A ConversionChangelog.txt file is also written to your project root with timestamped details of every modification.

After conversion, you can remove the old networking library from your project.

Creating your own converter

The tool uses a recipe system that makes it straightforward to add support for other networking libraries. Each converter lives in its own folder and consists of three classes.

1. Mappings

Extend NetworkSystemMappings and define your mappings in the constructor:

using PurrNet.ConversionTool;

public class MySystemMappings : NetworkSystemMappings
{
    public MySystemMappings()
    {
        SystemName = "MyNetworkLib";
        SystemIdentifiers = new List<string> { "MyNetworkLib" };

        NamespaceMappings = new Dictionary<string, string>
        {
            { "MyNetworkLib", "PurrNet" }
        };

        TypeMappings = new Dictionary<string, string>
        {
            { "NetConnection", "PlayerID" },
            { "NetObject", "NetworkIdentity" }
        };

        PropertyMappings = new Dictionary<string, string>
        {
            { "IsOwner", "isOwner" },
            { "IsServer", "isServer" }
        };

        MethodMappings = new Dictionary<string, string>
        {
            { "OnClientStart", "OnSpawned" }
        };

        // ... and so on for MemberMappings, MethodCallMappings,
        // AttributeMappings, AttributeParameterMappings, etc.
    }
}

For cases that don't fit into simple mappings, override SpecialCaseHandler to do custom Roslyn syntax tree transformations.

2. Prefab handling

Extend NetworkPrefabHandling and override ConvertPrefab:

using PurrNet.ConversionTool;
using UnityEngine;

public class MySystemPrefabHandling : NetworkPrefabHandling
{
    public override bool ConvertPrefab(GameObject prefab)
    {
        // Find old components, add PurrNet equivalents, copy settings
        // Return true if anything was changed
        return false;
    }
}

3. Scene handling

Extend NetworkSceneHandling and override ConvertSceneObject:

using PurrNet.ConversionTool;
using UnityEngine;

public class MySystemSceneHandling : NetworkSceneHandling
{
    public override bool ConvertSceneObject(GameObject sceneObject)
    {
        // Convert scene-specific objects like NetworkManager
        // Return true if anything was changed
        return false;
    }
}

Assembly setup

Your converter folder needs its own .asmdef that references PurrNet.ConversionTool and the source networking library. Set it to Editor only and add a defineConstraints entry so it only compiles when the source library is present.

Take a look at the FishNet converter for a full working example.

Discovery

The tool automatically discovers converters through reflection. As long as your three classes are in the same folder and extend the right base classes, they'll show up in the dropdown. No registration needed.

Links

PurrNet | Documentation | Discord

License

MIT

PurrConversion