WapcGuest 0.1.1

This library provides a C# implementation of the waPC standard for WebAssembly guest modules. It allows any waPC-compliant WebAssembly host to invoke to procedures inside a C# compiled guest and similarly for the guest to invoke procedures exposed by the host.

Requirements

The code requires .NET 7, which is currently (as of July 2022) in preview mode. Executing dotnet --version should return 7.0.100-preview.4 or later.

Usage

Create a Console application:

dotnet new console -o MyFirstWapcModule
cd MyFirstWapcModule
dotnet add package Wasi.Sdk --prerelease
dotnet add package WapcGuest

Edit the Program.cs file and replace its contents to match the following ones:

using WapcGuest;
using System.Text;

static byte[] callHost(byte[] payload)
{
  var binding = "binding_value";
  var wapcNamespace = "wapc_namespace_value";
  var operation = "operation_value";
  var payloadGuest = "This is the payload coming from the waPC guest";
  var payloadGuestBytes = Encoding.UTF8.GetBytes(payloadGuest);

  var hostResponseBytes = Wapc.HostCall(binding, wapcNamespace, operation, payloadGuestBytes);
  var hostResponse = Encoding.UTF8.GetString(hostResponseBytes);

  string response = $"the host responded with {hostResponse}";
  var responseBytes = Encoding.UTF8.GetBytes(response);

  return responseBytes;
}

static byte[] echo(byte[] payload)
{
  return payload;
}

var wapc = new Wapc();
wapc.RegisterFunction("echo", echo);
wapc.RegisterFunction("callHost", callHost);

Finally, build the WebAssembly module in this way:

dotnet build

You can now invoke both the echo and the callHost functions from any waPC host.