gRPC

What is gRPC?

gRPC is a high-performance RPC framework using HTTP/2 and Protocol Buffers for efficient communication between services.

gRPC vs REST

Aspect	gRPC	REST
Protocol	HTTP/2	HTTP/1.1
Format	Protocol Buffers (binary)	JSON (text)
Performance	Faster	Slower
Streaming	Built-in	Not supported
Browser Support	Limited	Full

Create gRPC Service

dotnet new grpc -n ProductService

Protocol Buffers (.proto)

syntax = "proto3";

option csharp_namespace = "ProductService";

service ProductService {
  rpc GetProduct (ProductRequest) returns (ProductReply);
  rpc ListProducts (Empty) returns (stream ProductReply);
}

message ProductRequest {
  int32 id = 1;
}

message ProductReply {
  int32 id = 1;
  string name = 2;
  double price = 3;
}

message Empty {}

Implement Service

public class ProductService : ProductService.ProductServiceBase
{
    private readonly InvenTrackDbContext _context;

    public override async Task<ProductReply> GetProduct(
        ProductRequest request, 
        ServerCallContext context)
    {
        var product = await _context.Products.FindAsync(request.Id);
        
        return new ProductReply
        {
            Id = product.Id,
            Name = product.Name,
            Price = (double)product.Price
        };
    }

    public override async Task ListProducts(
        Empty request, 
        IServerStreamWriter<ProductReply> responseStream, 
        ServerCallContext context)
    {
        var products = await _context.Products.ToListAsync();
        
        foreach (var product in products)
        {
            await responseStream.WriteAsync(new ProductReply
            {
                Id = product.Id,
                Name = product.Name,
                Price = (double)product.Price
            });
        }
    }
}

Register Service

builder.Services.AddGrpc();

var app = builder.Build();

app.MapGrpcService<ProductService>();

gRPC Client

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

using Grpc.Net.Client;

var channel = GrpcChannel.ForAddress("https://localhost:5001");
var client = new ProductService.ProductServiceClient(channel);

// Call service
var reply = await client.GetProductAsync(new ProductRequest { Id = 1 });
Console.WriteLine($"Product: {reply.Name}, Price: {reply.Price}");

Key Takeaways

• gRPC: High-performance RPC framework
• Protocol Buffers: Binary serialization format
• .proto files: Define service contracts
• HTTP/2: Faster than REST
• Streaming: Server/client/bidirectional streaming
• Best for: Microservices communication