This post is about Working with gRPC in ASP.NET Core. gRPC is a language agnostic, high-performance Remote Procedure Call (RPC) framework.
The main benefits of gRPC are:
- Modern high-performance lightweight RPC framework.
- Contract-first API development, using Protocol Buffers by default, allowing for language agnostic implementations.
- Tooling available for many languages to generate strongly-typed servers and clients.
- Supports client, server, and bi-directional streaming calls.
- Reduced network usage with Protobuf binary serialization.
If you’re using Visual Studio 2019, you will get gRPC project templates to build services with gRPC. gRPC templates will only available in .NET Core 3.0 projects.
Once you create a gRPC app, you will get two projects - one server project and one client project.
In the server project, the
proto files defines the services.
Protocol Buffers is a method of serializing structured data. It is developed by Google. Here is the default Greet service which comes as part of the template.
This definition is simple and straight forward. You’re creating a package, and a service with one
SayHello method. This method accepts one parameter
HelloRequest and returns a response object
HelloReply. That data structures as well included in the method. You can generate code from proto files - if you’re using Visual Studio, when you build the project, it will generate the code for you. It will generate
Greeter.GreeterBase and you need to write the implementation by inheriting from this class. So here is the implementation of
ServerCallContextparameter helps you to access HTTP/2 message data. You won’t get the
HttpContext from this parameter, there is one extension method available
GetHttpContext() which helps you to access the
In the server project, you can find reference of
Grpc.AspNetCore.Server package and
Google.Protobuf package. You will be able to find reference of
Grpc.Tools package reference, which is used to generate code from proto files. In the client project similar to server you will be able to find reference of
Grpc.Core package and
Google.Protobuf package. And the
Grpc.Tools as well. The proto files are added in a
Protos folder in the root level. Visual Studio will display it is a shortcut in both server and client projects.
startup.cs file, you need to add the
Grpc middleware in the
ConfigureServices() method and you need to map the implemented services in the
And in the client project, you can create an instance of
GreeterClient class and invoke the
SayHello method, like this.
This post was a very basic introduction to gRPC in ASP.NET Core. Here are some helpful resources about gRPC on .NET and C#.
Happy Programming :)