gRPC Unary Service

Giriş

- Cevap olarak döndürülecek nesneyi Builder yardımıyla yaratırız.

- Daha sonra responseObserver.onNext() çağrısına cevap nesnesini geçeriz.

- En son olarak ta responseObserver.OnCompleted() çağrısını yaparız

Örnek

Elimizde şöyle bir servis olsun

import com.grpc.hello.grpc.HelloGrpc.HelloImplBase;
import com.grpc.hello.grpc.HelloReply;
import com.grpc.hello.grpc.HelloReply.Builder;
import com.grpc.hello.grpc.HelloRequest;

import io.grpc.stub.StreamObserver;

public class HelloService extends HelloImplBase {
  @Override
  public void sayHello(HelloRequest request, StreamObserver<HelloReply> responseObserver) {
    Builder response = HelloReply.newBuilder();

    String caller = request.getName();
    String greet = "Hello " + caller;
    response.setMessage(greet);
    responseObserver.onNext(response.build());
    responseObserver.onCompleted();
  }
}

Örnek

Şöyle yaparız

@Override
public void hello(HelloRequest request, StreamObserver<HelloResponse> responseObserver) {

  String greeting = ...;

  HelloResponse response = HelloResponse.newBuilder()
    .setGreeting(greeting)
    .build();

  responseObserver.onNext(response);
  responseObserver.onCompleted();
}

Örnek - Hata Durumu

Şöye yaparız. Burada io.grpc.StatusException döndürülüyor

public class ProductService extends ProductServiceGrpc.ProductServiceImplBase {

  private final ProductRepository productRepository;

  public ProductService() {
    this.productRepository = new ProductRepository();
  }

  @Override
  public void getProduct(
      GetProductRequest request, StreamObserver<GetProductResponse> responseObserver) {
    var productId = request.getProductId();
    //Fetch Product information from repository
    Optional<Product> optionalProduct = productRepository.get(productId);

    if (optionalProduct.isPresent()) {
      var product = optionalProduct.get();
      //If found build response
      var productResponse =
          Service.Product.newBuilder()
              .setName(product.getName())
              .setDescription(product.getDescription())
              .setPrice(product.getPrice())
              .build();
      var getProductResponse = GetProductResponse.newBuilder()
        .setProduct(productResponse).build();

      responseObserver.onNext(getProductResponse);
      responseObserver.onCompleted();
    } else {
      responseObserver.onError(new StatusException(Status.NOT_FOUND));
    }
    log.info("Finished calling Product API service..");
  }
}