public async Task <IActionResult> CreateBookCollection( [FromBody] IEnumerable <BookCreationDto> bookCollection) // [FromBody] --> request body - [FromUri] --> query string { //todo:Author id is really exist? var newCollection = _mapper.Map <IEnumerable <Book> >(bookCollection); _bookRepository.AddMultipleBook(newCollection); await _bookRepository.SaveChangesAsync(); var allBooks = await _bookRepository.GetMultipleBooksAsync( newCollection.Select(c => c.Id).ToList()); var allBookIds = string.Join(",", allBooks.Select(c => c.Id)); return(CreatedAtRoute("GetBookCollection", new { bookIds = allBookIds }, allBooks)); }