How do you create a gRPC client in .NET Framework?

Question

I followed the instructions at:

https://docs.microsoft.com/en-us/aspnet/core/tutorials/grpc/grpc-start?view=aspnetcore-3.1&tabs=visual-studio

to create a

Answer 1

you can configure the .Net core grpc server on insecure through config

There are 2 ways,

launchSettings,json

{
  "profiles": {
    "DemoService": {
      "commandName": "Project",
      "launchBrowser": false,
      "applicationUrl": "http://localhost:5001",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    }
  }
}

Or

appsettings,json

"Kestrel": {
    "EndpointDefaults": {
      "Protocols": "Http2"
    },
    "EndPoints": {
      "Http": {
        "Url": "http://localhost:5001"
      }
    }
  }

Answer 2

Over SSL or not, you need to turn on Http2 in ASP.NET Core server. So in appsettings.json, do this.

"Kestrel": {
    "EndpointDefaults": {
      "Protocols": "Http2"
    }

Insecure .NET Framework Client + ASP.NET Core Server

• ASP.NET Core Server
  1. Remove app.UseHttpsRedirection() and app.UseHsts() in the StartUp class ConfigureServices(IApplicationBuilder app);
  2. Expose the insecure port, typically 80 or 5000 during development.
  3. Use the code below to create insecure channel in .NET Framework client.

var channel = new Channel("localhost", 5001, secureCredentials);

Secure SSL connection .NET Framework Client + ASP.NET Core Server

I got it working with SSL port by using the same Server's certificate in .pem format in the client.

SslCredentials secureCredentials = new SslCredentials(File.ReadAllText("certificate.pem"));
var channel = new Channel("localhost", 5001, secureCredentials);

A bit of explanation. An ASP.NETCore template in VS 2019 uses a development certificate with pfx file at %AppData%\ASP.NET\Https\ProjectName.pfx and password = %AppData%\Microsoft\UserSecrets\{UserSecretsId}\secrets.json {:Kestrel:Certificates:Development:Password} Value You can get the UserSecretsId id from the ProjectName.csproj. This will be different for each ASP.NET Core Project.

I used the below command to convert the pfx + password combination to a certificate.pem file.

openssl pkcs12 -in "<DiskLocationOfPfx>\ProjectName.pfx" -out "<TargetLocation>\certifcate.pem" -clcerts

This will prompt for the pfx password. Use the password from the above secrets.json.

Give some passphrase for the certificate.pem to be generated(At least 4 letter).

Copy this cerificate.pem for the gRPC .NET Framework client to access and use in

SslCredentials secureCredentials = new SslCredentials(File.ReadAllText("<DiskLocationTo the Folder>/certificate.pem"))
var channel = new Channel("localhost", 5001, secureCredentials);

Note that port 5001 I used is the SSL port of my ASP.NET Core application.

For Production Scenarios

Use a valid certificate from certificate signing authority and use same certificate in ASP.NET Core Server and .NET Framework client as pfx and pem respectively.