GRPC

Introduction

gRPC is a high-performance, open-source RPC framework that uses Protocol Buffers for serialization and HTTP/2 for transport. It enables efficient communication between services across different languages and platforms.

Define Your Service, Messages

syntax = "proto3";

package dvdrental.v1;

import "google/protobuf/empty.proto";

option go_package = "git.bibble.co.nz/bibble235/grpc_server_go/pb;pb";

// Film represents a movie in the DVD rental system
message Film {
  // Unique identifier for the film
  string id = 1;
  // Title of the film
  string title = 2;
  // Description or synopsis of the film
  string description = 3;
  // Year the film was released
  string release_year = 4;
}

// Actor represents a person who acts in films
message Actor {
  // Unique identifier for the actor
  string id = 1;
  // First name of the actor
  string first_name = 2;
  // Last name of the actor
  string last_name = 3;
}

// ActorList contains multiple Actor records
message ActorList {
  // List of actors
  repeated Actor actor = 1;
}

// FilmList contains multiple Film records
message FilmList {
  // List of films
  repeated Film film = 1;
}

// FilmIdRequest is used to request a specific film by ID
message FilmIdRequest {
  // ID of the film to retrieve
  string id = 1;
}

// ActorIdRequest is used to request a specific actor by ID
message ActorIdRequest {
  // ID of the actor to retrieve
  string id = 1;
}

// DVDRentalService provides operations to interact with the DVD rental system
service DVDRentalService {
  // GetActor retrieves an actor by their ID
  rpc GetActor(ActorIdRequest) returns (Actor);
  
  // GetActorListWithStream streams all actors one by one
  rpc GetActorListWithStream(google.protobuf.Empty) returns (stream Actor);
  
  // GetActorListWithRepeated retrieves all actors in a single response
  rpc GetActorListWithRepeated(google.protobuf.Empty) returns (ActorList);

  // GetFilm retrieves a film by its ID
  rpc GetFilm(FilmIdRequest) returns (Film);
  
  // GetFilmListWithStream streams all films one by one
  rpc GetFilmListWithStream(google.protobuf.Empty) returns (stream Film);
  
  // GetFilmListWithRepeated retrieves all films in a single response
  rpc GetFilmListWithRepeated(google.protobuf.Empty) returns (FilmList);
}

Csharp

Lets start with a CSharp client

dotnet new console -n grpc_client_cs
cd grpc_client_cs
mkdir -p api/proto/v1

Add the dependencies

dotnet add package Grpc.Net.Client
dotnet add package Google.Protobuf
dotnet add package Grpc.Tools

Add the proto top the project.

  <ItemGroup>
    <Protobuf Include="api/proto/v1/dvdrental.proto" GrpcServices="Client" />
  </ItemGroup>

For basic client we have

using Grpc.Net.Client;
using Dvdrental.V1;
using Google.Protobuf.WellKnownTypes;

var channel = GrpcChannel.ForAddress("https://localhost:50051");
var client = new DVDRentalService.DVDRentalServiceClient(channel);

// Example: Get an actor by ID
var actorRequest = new ActorIdRequest { Id = "1" };
var actor = await client.GetActorAsync(actorRequest);

Console.WriteLine($"Actor: {actor.FirstName} {actor.LastName}");

// Example: Get all films (repeated)
var filmsResponse = await client.GetFilmListWithRepeatedAsync(new Empty());
foreach (var film in filmsResponse.Film)
{
    Console.WriteLine($"Film: {film.Title} ({film.ReleaseYear})");
}

Lets add oauth.

dotnet add package Microsoft.Extensions.Http