Grpc.AspNetCore.Web

Grpc.AspNetCore.Web provides middleware that enables ASP.NET Core gRPC services to accept gRPC-Web calls.

In Startup.cs:

public void ConfigureServices(IServiceCollection services)
{
    services.AddGrpc();
    services.AddGrpcWeb(o => o.GrpcWebEnabled = true);
}

public void Configure(IApplicationBuilder app)
{
    app.UseRouting();
    app.UseGrpcWeb();
    app.UseEndpoints(endpoints =>
    {
        endpoints.MapGrpcService<GreeterService>();
    });
}

gRPC-Web can be enabled for all gRPC services by setting GrpcWebOptions.GrpcWebEnabled = true, or enabled on individual services with EnableGrpcWeb():

app.UseEndpoints(endpoints =>
{
    endpoints.MapGrpcService<GreeterService>().EnableGrpcWeb();
});

gRPC-Web and streaming

Traditional gRPC over HTTP/2 supports streaming in all directions. gRPC-Web offers limited support for streaming:

• gRPC-Web browser clients don't support calling client streaming and bidirectional streaming methods.
• gRPC-Web .NET clients don't support calling client streaming and bidirectional streaming methods over HTTP/1.1.
• ASP.NET Core gRPC services hosted on Azure App Service and IIS don't support bidirectional streaming.

When using gRPC-Web, we only recommend the use of unary methods and server streaming methods.

Links

• Documentation
• grpc-dotnet GitHub