gRPC Proxy

Client based proxy code generator using source generator

for build man-in-the-middle attack gRPC server.

Getting started

Install-Package Evan.Grpc.Proxy
Install-Package Evan.Grpc.Proxy.Tools

var targetChannel = new Channel("127.0.0.1", 12345, ChannelCredentials.Insecure);
var targetInvoker = new ProxyCallInvoker(targetChannel.CreateCallInvoker());

var proxyService1 = new Example1.Example1Proxy(targetInvoker); // auto-generated proxy client
var proxyService2 = new Example2.Example2Proxy(targetInvoker); // auto-generated proxy client

var proxyServer = new Server();
server.Services.Add(Example1.BindService(proxyService1));
server.Services.Add(Example2.BindService(proxyService2));

Advanced usage

Extends auto-generated proxy client and intercept request/response

public sealed class ExampleImpl : Example.ExampleProxy
{
    public TestProxy(IProxyCallInvoker callInvoker) : base(callInvoker)
    {
    }
    
    public override async Task<HelloResponse> Hello(HelloRequest request, ServerCallContext context)
    {
        request.Message = "I'm proxy!";

        var response = await base.Hello(request, context);
        
        response.Message += ", Decorated by proxy!";

        return response;
    }
}

Dynamic Routing

Dynamic routing operates based on the method defined in ServiceDescriptor.

var targetChannelA = new Channel("1.2.3.4", 12345, ChannelCredentials.Insecure);
var targetInvokerA = targetChannelA.CreateCallInvoker();

var targetChannelB = new Channel("4.3.2.1", 54321, ChannelCredentials.Insecure);
var targetInvokerB = targetChannelB.CreateCallInvoker();

var proxyRouter = new ProxyCallRouter();

proxyRouter.Add(Example1.Descriptor, targetInvokerA); // Example1 -> 1.2.3.4:12345
proxyRouter.Add(Example2.Descriptor, targetInvokerB); // Example2 -> 4.3.2.1:54321

/* Setup Proxy Server */

var proxyServer = new Server();
server.Services.Add(Example1.BindService(new Example1.Example1Proxy(proxyRouter)));
server.Services.Add(Example2.BindService(new Example2.Example2Proxy(proxyRouter)));