---
title: gRPC services with ASP.NET Core
author: juntaoluo
description: Learn the basic concepts when writing gRPC services with ASP.NET Core.
monikerRange: '>= aspnetcore-3.0'
ms.author: johluo
ms.date: 03/08/2019
uid: grpc/aspnetcore
---
# gRPC services with ASP.NET Core

This document shows how to get started with gRPC services using ASP.NET Core.

[!INCLUDE[](~/includes/net-core-prereqs-all-3.0.md)]

## Get started with gRPC service in ASP.NET Core

[!INCLUDE[View or download sample code](~/includes/grpc/download.md)]

# [Visual Studio](#tab/visual-studio)

See [Get started with gRPC services](xref:tutorials/grpc/grpc-start) for detailed instructions on how to create a gRPC project.

# [Visual Studio Code / Visual Studio for Mac](#tab/visual-studio-code+visual-studio-mac)

Run `dotnet new grpc -o GrpcGreeter` from the command line.

---

## Add gRPC services to an ASP.NET Core app

gRPC requires the following packages:

* [Grpc.AspNetCore.Server](https://www.nuget.org/packages/Grpc.AspNetCore.Server)
* [Google.Protobuf](https://www.nuget.org/packages/Google.Protobuf/) for protobuf message APIs.
* [Grpc.Tools](https://www.nuget.org/packages/Grpc.Tools/)

### Configure gRPC

gRPC is enabled with the `AddGrpc` method:

[!code-cs[](~/tutorials/grpc/grpc-start/samples/GrpcGreeter/Startup.cs?name=snippet&highlight=5)]

Each gRPC service is added to the routing pipeline through the `MapGrpcService` method:

[!code-cs[](~/tutorials/grpc/grpc-start/samples/GrpcGreeter/Startup.cs?name=snippet&highlight=21)]

ASP.NET Core middlewares and features share the routing pipeline, therefore an app can be configured to serve additional request handlers. The additional request handlers, such as MVC controllers, work in parallel with the configured gRPC services.

## Integration with ASP.NET Core APIs

gRPC services have full access to the ASP.NET Core features such as [Dependency Injection](xref:fundamentals/dependency-injection) (DI) and [Logging](xref:fundamentals/logging/index). For example, the service implementation can resolve a logger service from the DI container via the constructor:

```csharp
public class GreeterService : Greeter.GreeterBase
{
    public GreeterService(ILogger<GreeterService> logger)
    {
    }
}
```

By default, the gRPC service implementation can resolve other DI services with any lifetime (Singleton, Scoped, or Transient).

### Resolve HttpContext in gRPC methods

The gRPC API provides access to some HTTP/2 message data, such as the method, host, header, and trailers. Access is through the `ServerCallContext` argument passed to each gRPC method:

[!code-cs[](~/tutorials/grpc/grpc-start/samples/GrpcGreeter/Services/GreeterService.cs?highlight=3-4&name=snippet)]

`ServerCallContext` does not provide full access to `HttpContext` in all ASP.NET APIs. The `GetHttpContext` extension method provides full access to the `HttpContext` representing the underlying HTTP/2 message in ASP.NET APIs:

[!code-cs[](~/tutorials/grpc/grpc-start/samples/GrpcGreeter/Services/GreeterService.cs?name=snippet1)]

### Request body data rate limit

By default, the Kestrel server imposes a [minimum request body data rate](
<xref:Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServerLimits.MinRequestBodyDataRate>). For client streaming and duplex streaming calls, this rate may not be satisfied and the connection may be timed out. The minimum request body data rate limit must be disabled when the gRPC service includes client streaming and duplex streaming calls:

```csharp
public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
         Host.CreateDefaultBuilder(args)
    .ConfigureWebHostDefaults(webBuilder =>
    {
        webBuilder.UseStartup<Startup>();
        webBuilder.ConfigureKestrel((context, options) =>
        {
            options.Limits.MinRequestBodyDataRate = null;
        });
    });
}
```

## Additional resources

* <xref:tutorials/grpc/grpc-start>
* <xref:grpc/index>
* <xref:grpc/basics>
* <xref:grpc/migration>