Spring Boot + C# gRPC Hello World Example

In previous tutorial we had created a spring boot gRPC server and spring boot gRPC client. Before gRPC was developed, Remote Procedure Call (RPC) was a communication protocol used to enable inter-process communication between different systems. One major drawback was its tight coupling with specific programming languages and platforms. gRPC uses Protocol Buffers as its interface definition language, allowing you to define services and messages in a language-agnostic way. So we will be using the same proto files both at the spring boot server and C# client end.

gRPC - Table of Contents
Spring Boot+ gRPC Hello World Example
Spring Boot gRPC Server + C# gRPC Client Example
Spring Boot 3 + gRPC - Types of gRPC
Spring Boot 3 + gRPC Unary Example
Spring Boot 3 + gRPC Server Streaming Example
Spring Boot 3 + gRPC Client Streaming Example
Spring Boot 3 + gRPC Bidirectional Streaming Example
Spring Boot + gRPC Deadline Example
Spring Boot + gRPC Error Handling Example
Spring Boot + gRPC Error Handling - Using Trailer Metadata
Spring Boot + gRPC Error Handling - Global Exception Handler Using GrpcAdvice

Implementation

We will be making use of the Spring Boot gRPC server code that we had developed in previous tutorial. The maven project we will be creating is as follows -

Start the spring boot project, the gRPC server gets started on port 9090.

C# Client Example

Start Visual Studio, and create a new console application.





Create a folder name proto with the same proto files that we used in spring boot project.

syntax = "proto3";

import "Protos/constant/util.proto";

option java_multiple_files = true;
option java_package = "com.javainuse.employee";

option csharp_namespace = "com.javainuse.employee";


message BookRequest{
  string book_id = 1;
}
message BookResponse {
  string book_id = 1;
  string name = 2;
  constants.Type type = 3;
}

service BookService {
  rpc getBook(BookRequest) returns (BookResponse) {};
}

The above proto file makes use of another proto file named util.proto where we define the enum Type.

syntax = "proto3";

package constants;

option java_multiple_files = true;
option java_package = "com.javainuse.constants";

option csharp_namespace = "com.javainuse.constants";

enum Type {
  FANTASY = 0;
  AUTOBIOGRAPHY = 1;
  HISTORY = 2;
}

Next to the console application we will be adding dependencies Manage NuGet Packages.

These dependencies are

• Google.Protobuf
  
  
• Grpc.Net.Client
  
  
• Grpc.Tools
  
  

Next write click on the proto file and go to properties. Here select build action as Protobuf compiler and gRPC stub classes as Client only.

Do the same for both proto files.
Next right click on the project and build it.

Next in the Program.cs file we will be making use of the gRPC client to consume the endpoint exposed by the spring boot gRPC server.

// See https://aka.ms/new-console-template for more information
using com.javainuse.employee;
using Grpc.Net.Client;

Console.WriteLine("Hello, World!");

var channel = GrpcChannel.ForAddress("http://localhost:8090");
var client = new BookService.BookServiceClient(channel);
bookRequest bookRequest = new bookRequest();
bookRequest.BookId = "1";
var reply = await client.getBookAsync(bookRequest);

Console.WriteLine(reply.ToString());

Run the console application. We can see that it consumes the exposed gRPC endpoint.

Download Source Code

Download it - C# + gRPC Client Example
Download it - Spring Boot + gRPC Server Example