experimental

This directory contains useful resources for getting gRPC C# to work on platforms that are not yet fully supported.

Xamarin

gRPC C# now has experimental support for Xamarin. See HelloworldXamarin for an example how to use it.

Starting from gRPC C# 2.34.x: in addition to the regular Grpc.Core dependency, you will also need to add Grpc.Core.Xamarin dependency to your project (which has the mobile-specific builds of c# native extension library). The Grpc.Core and Grpc.Core.Xamarin package versions must always match exactly for things to work. Also note that the Grpc.Core.Xamarin needs to be added to your *.Android and *.iOS projects in order for the native library bindings to be registered correctly (see grpc#16250).

What's currently supported:

Xamarin.Android

• supported API level: Kitkat 4.4+ (= API level 19)
• supported ABIs: armeabi-v7a (vast majority of Android devices out there), arm64-v8a (some newer Android devices), x86 (for emulator)

Xamarin.iOS

• supported architectures: armv7, arm64 (iPhone 6+) and x86_64 (iPhone simulator)

Unity

gRPC C# now has experimental support for Unity. Please try using gRPC with Unity and provide feedback!

How to test gRPC in a Unity project

1. Create a Unity project that targets .NET 4.x Equivalent (Edit -> Project Settings -> Player -> Configuration -> Scripting Runtime Version). gRPC uses APIs that are only available in .NET4.5+ so this is a requirement.

2. Download the latest development build of grpc_unity_package.VERSION.zip from daily builds

3. Extract the .zip file in the Assets directory in your Unity project

4. Unity IDE will pick up all the bundled files and add them to project automatically. You should be able to use gRPC and Protobuf in your scripts from now on.

5. (optional) Extra steps for iOS, see below

What's currently bundled in the grpc_unity_package

• Grpc.Core and its dependencies
• Google.Protobuf
• Precompiled native libraries for Linux, MacOS, Windows, Android and iOS.

Please note that Grpc.Core is now in maintenance mode (see The future of gRPC in C# belongs to grpc-dotnet). There is a plan to support Unity in Grpc.Net.Client, which depends on Unity's .NET 5 or .NET 6 support. See this issue for more information.

Building for iOS

To build a Unity app on iOS, there are extra steps to do to make it work:

1. Add a Assets/link.xml asset file to your Unity project with the following content:

   <linker>
       <assembly fullname="UnityEngine">
          <type fullname="UnityEngine.Application" preserve="fields">
               <property name="platform"/>
           </type>
       </assembly>
   </linker>

   If you don't, you might encounter the following error: System.IO.FileNotFoundException: Error loading native library. Not found in any of the possible locations: with a list of paths that point to the libgrpc_csharp_ext.x64.dylib file.
2. Due to the growing build size, bitcode has been disabled for the gRPC library. You must disable it in your XCode project as well.
3. Add the libz framework.

Steps 2 and 3 can be automated by adding the following Assets/Scripts/BuildIos.cs script in your Unity project, and attaching it to a Unity game object:

#if UNITY_EDITOR && UNITY_IOS
using System.IO;
using UnityEngine;
using UnityEditor;
using UnityEditor.Callbacks;
using UnityEditor.iOS.Xcode;

public class BuildIos
{
  [PostProcessBuild]
  public static void OnPostProcessBuild(BuildTarget target, string path)
  {
    var projectPath = PBXProject.GetPBXProjectPath(path);
    var project = new PBXProject();
    project.ReadFromString(File.ReadAllText(projectPath));
#if UNITY_2019_3_OR_NEWER
    var targetGuid = project.GetUnityFrameworkTargetGuid();
#else
    var targetGuid = project.TargetGuidByName(PBXProject.GetUnityTargetName());
#endif

    // libz.tbd for grpc ios build
    project.AddFrameworkToProject(targetGuid, "libz.tbd", false);

    // bitode is disabled for libgrpc_csharp_ext, so need to disable it for the whole project
    project.SetBuildProperty(targetGuid, "ENABLE_BITCODE", "NO");

    File.WriteAllText(projectPath, project.WriteToString());
  }
}
#endif