How can I make a GRPC call for a service which is inside a subdirectory? (in .Net Framework)

Question

I am trying to connect to a gRPC service in a .NetFramework 4.5 windows application. I am currently using metapackage nuget Grpc which I know is only in maintenance mode now...

I need to access the service which is not at a host:port location, but has a subpath, subdirectory. My service is located here "https://example.com/mySubpath"

Is there a way to specify a subdirectory, subpath for gRPC calls in .NetFramework?

• For .NetFramework4.5, if I specify the full path (which contains the "mySubpath" part) it doesn't work

var channel = new Channel("example.com/mySubpath", ChannelCredentials.SecureSsl);

I saw that I could also add a List<ChannelOption> parameter to the Channel constructor, but don't know if there is one option which I could use for that.

• I am currently trying to upgrade to .NetFramework 4.6.1 to see if I can use Grpc.Net.Client which I understood it has some support over .NetFramework 4.6.1 if a WinHttpHandler is used. (https://learn.microsoft.com/en-us/aspnet/core/grpc/netstandard?view=aspnetcore-6.0)

I have found a solution here https://github.com/grpc/grpc-dotnet/issues/880 for .NetCore and I am trying to see if I can use that to the .NetFramework 4.6. I used the SubdirectoryHandler class as it is defined in the link to change the RequestUri and assigned a WinHttpHandler

var handler = new SubdirectoryHandler(new WinHttpHandler(), subpath);
var httpClient = new HttpClient(handler);
GrpcChannel channel = GrpcChannel.ForAddress(address, new GrpcChannelOptions { HttpClient = httpClient });
            

but I am getting an exception related to assembly System.Buffers, Version=4.0.2.0.

StatusCode="Unavailable",
Detail="Error starting gRPC call. HttpRequestException: Error while copying content to a stream. FileLoadException: Could not load file or assembly 'System.Buffers, Version=4.0.2.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)",

I think this is because Grpc.Net.Client references version=4.0.2.0, while the System.Net.Http.WinHttpHandler references version 4.0.3.0.

Any idea what I need to change to be able to use the subdirectory,subpath for .NetFramework 4.6.1 or for .NetFramework4.5?