book_service.go

import pb_library "../_proto/examplecom/library"

type bookService struct{
        books []*pb_library.Book
}

func (s *bookService) GetBook(ctx context.Context, bookQuery *pb_library.GetBookRequest) (*pb_library.Book, error) {
	for _, book := range s.books {
		if book.Isbn == bookQuery.Isbn {
			return book, nil
		}
	}
	return nil, grpc.Errorf(codes.NotFound, "Book could not be found")
}

func (s *bookService) QueryBooks(bookQuery *pb_library.QueryBooksRequest, stream pb_library.BookService_QueryBooksServer) error {
	for _, book := range s.books {
		if strings.HasPrefix(s.book.Author, bookQuery.AuthorPrefix) {
			stream.Send(book)
		}
	}
	return nil
}