Do you like WCF-like approach and need to cover communication in between ASP.NET Core service and Blazor WebAssembly client? Use code-first with gRPC-Web! You can try the it right now by following a few simple steps (commit):
Add NuGet packages:
- Grpc.AspNetCore.Web (prerelease)
- protobuf-net.Grpc.AspNetCore
Register CodeFirstGrpc() and GrpcWeb() services in Startup.cs ConfigureServices() method:
services.AddCodeFirstGrpc(config => { config.ResponseCompressionLevel = System.IO.Compression.CompressionLevel.Optimal; });Add GrpcWeb middleware in between UseRouting() and UseEndpoints():
app.UseGrpcWeb(new GrpcWebOptions() { DefaultEnabled = true });Add System.ServiceModel.Primitives NuGet package.
Define the interface of your service:
[ServiceContract]
public interface IMyService
{
Task DoSomething(MyServiceRequest request);
}
[DataContract]
public class MyServiceResult
{
[DataMember(Order = 1)]
public string NewText { get; set; }
[DataMember(Order = 2)]
public int NewValue { get; set; }
}
[DataContract]
public class MyServiceRequest
{
[DataMember(Order = 1)]
public string Text { get; set; }
[DataMember(Order = 2)]
public int Value { get; set; }
}Implement your service:
public class MyService : IMyService
{
public Task DoSomething(MyServiceRequest request)
{
return Task.FromResult(new MyServiceResult()
{
NewText = request.Text + " from server",
NewValue = request.Value + 1
});
}
}Publish the service in Startup.cs:
app.UseEndpoints(endpoints =>
{
endpoints.MapGrpcService<MyService>();
// ...
}Add NuGet packages:
- Grpc.Net.Client
- Grpc.Net.Client.Web (prerelease)
- protobuf-net.Grpc
Consume the service in your razor file:
var handler = new Grpc.Net.Client.Web.GrpcWebHandler(Grpc.Net.Client.Web.GrpcWebMode.GrpcWeb, new HttpClientHandler());
using (var channel = Grpc.Net.Client.GrpcChannel.ForAddress("https://localhost:44383/", new Grpc.Net.Client.GrpcChannelOptions() { HttpClient = new HttpClient(handler) }))
{
var testFacade = channel.CreateGrpcService<IMyService>();
this.result = await testFacade.DoSomething(request);
}Register a GrpcChannel in your Program.cs (or Startup.cs:ConfigureServices())
builder.Services.AddSingleton(services =>
{
// Get the service address from appsettings.json
var config = services.GetRequiredService<IConfiguration>();
var backendUrl = config["BackendUrl"];
// If no address is set then fallback to the current webpage URL
if (string.IsNullOrEmpty(backendUrl))
{
var navigationManager = services.GetRequiredService<NavigationManager>();
backendUrl = navigationManager.BaseUri;
}
// Create a channel with a GrpcWebHandler that is addressed to the backend server.
//
// GrpcWebText is used because server streaming requires it. If server streaming is not used in your app
// then GrpcWeb is recommended because it produces smaller messages.
var httpHandler = new GrpcWebHandler(GrpcWebMode.GrpcWeb, new HttpClientHandler());
return GrpcChannel.ForAddress(
backendUrl,
new GrpcChannelOptions
{
HttpHandler = httpHandler,
//CompressionProviders = ...,
//Credentials = ...,
//DisposeHttpClient = ...,
//HttpClient = ...,
//LoggerFactory = ...,
//MaxReceiveMessageSize = ...,
//MaxSendMessageSize = ...,
//ThrowOperationCanceledOnCancellation = ...,
});
});Register the individual services (you might want to extract the "logic" to an extension method for better readability).
builder.Services.AddTransient<IMyService>(services =>
{
var grpcChannel = services.GetRequiredService<GrpcChannel>();
return grpcChannel.CreateGrpcService<IMyService>();
});And now you can consume the services whereever needed (e.g. from .razor file):
@inject IMyService MyService
@code
{
async Task Submit()
{
this.result = await MyService.DoSomething(request);
}
}For more advanced usage with error-handling, authentication + authorization and more, see our Havit.Blazor project template:
- Steve Sanderson: Using gRPC-Web with Blazor WebAssembly
- Use gRPC in browser apps | Microsoft Docs
- protobuf-net.Grpc - Getting Started
- https://github.com/grpc/grpc-dotnet/blob/master/examples/Blazor/Client/Program.cs
- credits to @dani-herrera-udg for upgrading to .NET 6
- dotnet/runtime#62054 - may be hitting GC bug in .NET6