README.md

gRPC .NET client with Unity

This README will guide you to set up a new Unity project and to configure a .NET gRPC client in C#.

Create a new project

Open Unity Hub, click on New Project. In the new window, select 3D in the Core category. Set the project name and the wanted location in the right panel. Click on Create Project.

Install dependencies

The gRPC .NET client is avalaible through the Nuget ecosystem. Unity doesn't support it natively, so we had to add a module (NuGetForUnity) to be able to install it easily. Please install NuGetForUnity by following the README on their github page and come back here.

Upon the installation complete, restart Unity to have the new NuGet menu. Select Nuget -> Manage NuGet Packages. Search and install these packages:

• Grpc.Net.Client
• Grpc.Net.Client.Web
• Google.Protobuf

Copy API dependencies

We will copy the generated GnoNative API files and gRPC C# stubs into Assets/Gno.

In a terminal, cd to your Unity project folder and write this command (replace ${gnonative} by the location where is gnonative in your filesystem):

cp -r ${gnonative}/api/gen/csharp Assets/GnoNative

Create a C# script

In the project panel, click on the Assets folder to select it. Then click on the + sign and click on C# script. Name the new file Hello.

Double click on it to open it in Visual Studio. Replace the content with:

using System;
using System.Net.Http;
using UnityEngine;
using TMPro;

using Grpc.Net.Client;
using Grpc.Net.Client.Web;
using Land.Gno.Gnonative.V1;

public class Hello : MonoBehaviour
{
    public TextMeshProUGUI Text;

    private GrpcChannel channel;
    private GnoNativeService.GnoNativeServiceClient client;

    // Start is called before the first frame update
    void Start()
    {
        var options = new GrpcChannelOptions();
        var handler = new GrpcWebHandler(GrpcWebMode.GrpcWeb, new HttpClientHandler());
        options.HttpHandler = handler;

        channel = GrpcChannel.ForAddress("http://localhost:26658", options);
        client = new GnoNativeService.GnoNativeServiceClient(channel);
    }

    private void OnDestroy()
    {
        channel.Dispose();
    }

    public void OnHello()
    {
        var reply = client.Hello(new HelloRequest { Name = "Gno" });
        Debug.Log(reply.Greeting.ToString());
        Text.text = $"[{DateTime.Now}] {reply.Greeting}";
    }
}

In the Start() function, we initialize the gRPC client with the gRPC Web protocol and use the default GnoNative port. In the OnHello() function, we do the Hello gRPC call and set the result into the Text object. This function can be triggered by a button for example.

Save the modifications and go back to Unity.

We have to link the script with an object in the scene. So in the Hierarchy panel, click on the + sign and Create Empty. Name it UI Script. From the Project panel, drag and drop the Hello script to the UI Script object in the Hierarchy panel.

Create UI objects

We want to create a button and a text objects on the scene to start the GnoNative call and print the result.

In the Hierarchy panel, click on the + sign and select UI and Text - TextMeshPro. In the TMP Importer windows, click on Import TMP Essentials and close it. Still in the UI section, add a Button - TextMeshPro. You can move the objects in the scene to make it clean.

Now we have to attach these two objects to the script we wrote:

• In the Hierarchy panel, select the button. Scroll down on the Inspector (right panel) to find the On Click section and click on + to add a new action. Drag and drop the UI Script object to the None (Object) in this action, and replace No Function by Hello.OnHello().
• In the Hierarchy panel, click on UI Script. In the Inspector panel, you can see the Hello (Script) section with the empty Text field. Drag and drop the Text object (in the Hierarchy) to this Text field (in the Inspector).

Play

In a terminal, go to gnonative/goserver and run the gRPC server:

go run . tcp

In Unity, click on the play button and click to the button on the scene. The text object should change.