Batch Create

func (s *linkServer) BatchCreateLinks(stream pb.LinkService_BatchCreateLinksServer) error {
	var created []*pb.Link

	for {
		req, err := stream.Recv()
		if err == io.EOF {
			// Client is done — send the summary and close
			return stream.SendAndClose(&pb.BatchCreateLinksResponse{
				CreatedCount: int64(len(created)),
				Links:        created,
			})
		}
		if err != nil {
			return err
		}

		id := s.nextID.Add(1)
		link := &pb.Link{
			Id:        id,
			Url:       req.GetUrl(),
			ShortCode: shortCode(),
		}

		s.mu.Lock()
		s.links[link.ShortCode] = link
		s.mu.Unlock()
		created = append(created, link)
	}
}

package main

import (
	"context"
	"fmt"
	"log"
	"time"

	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"

	"shortener/pb"
)

func main() {
	conn, err := grpc.NewClient("localhost:50051",
		grpc.WithTransportCredentials(insecure.NewCredentials()),
	)
	if err != nil {
		log.Fatal(err)
	}
	defer conn.Close()

	client := pb.NewLinkServiceClient(conn)
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	// Open the stream
	stream, err := client.BatchCreateLinks(ctx)
	if err != nil {
		log.Fatal(err)
	}

	// Send URLs one by one
	urls := []string{
		"https://example.com/article-one",
		"https://example.com/article-two",
		"https://example.com/article-three",
	}
	for _, url := range urls {
		if err := stream.Send(&pb.CreateLinkRequest{Url: url}); err != nil {
			log.Fatal(err)
		}
		fmt.Printf("sent: %s\n", url)
	}

	// Close sending side and get the response
	resp, err := stream.CloseAndRecv()
	if err != nil {
		log.Fatal(err)
	}

	fmt.Printf("\ncreated %d links:\n", resp.GetCreatedCount())
	for _, link := range resp.GetLinks() {
		fmt.Printf("  %s -> %s\n", link.GetShortCode(), link.GetUrl())
	}
}

sent: https://example.com/article-one
sent: https://example.com/article-two
sent: https://example.com/article-three

created 3 links:
  k7m2px -> https://example.com/article-one
  a3f9wq -> https://example.com/article-two
  zt04bn -> https://example.com/article-three