getBookByISBN method

Future<OLBookBase> getBookByISBN({ required String isbn, bool loadCover = true, CoverSize coverSize = CoverSize.L, })

This function getBookByISBN fetches a book by it's ISBN number (10 or 13 digits) from OpenLibrary.org. Always check RuntimeType OLBookBase type is -> OLBook / OLBookError use loadCover to indicate if the cover should be loaded, default = true and coverSite to define the loaded size, M,S,L from enum CoverSize, default = L

Implementation

Future<OLBookBase> getBookByISBN(
    {required String isbn,
    bool loadCover = true,
    CoverSize coverSize = CoverSize.L}) async {
  // try to fetch the book via isbn from the openlibrary.org isbn api
  final APIBookBase book =
      await _openLibraryApiService.getBookByISBN(isbn: isbn);
  if (book is APIBook) {
    // fetch Authors if exist
    final List<OLAuthor> authors = [];
    if (book.authors.isNotEmpty) {
      // each author needs to be fetched from openlibrary.org
      await Future.forEach(book.authors, (Map<String, String> element) async {
        if (element.keys.contains('key')) {
          final String id = element['key'] ?? '';
          if (id.isNotEmpty) {
            // the api wraps the id so we can remove path elements here
            final APIAuthorBase author = await _openLibraryApiService
                .getAuthorById(id: id.replaceFirst('/authors/', ''));
            if (author is APIAuthor) {
              authors.add(OLAuthor.fromJson(author.toJson()));
            }
          }
        }
      });
    }

    // fetch covers if exists
    final List<Uint8List> covers = [];
    if (book.covers.isNotEmpty && loadCover) {
      // each cover needs to be downloaded from the openlibrary.org covers endpoint
      await Future.forEach(book.covers, (int coverId) async {
        // we will provide byte data as Uint8List so it can be used directly as MemoryImage
        final Uint8List cover =
            await getCover(coverId: coverId, coverSize: coverSize);
        if (cover.isNotEmpty) {
          covers.add(cover);
        }
      });
    }

    // creates a new OLBook instance to be returned as data copy of
    // it's api transfer object APIBook with added authors and covers
    return _olBookFromAPIBook(book: book, authors: authors, covers: covers);
  }
  // in the case of an error return the Error Instance
  return const OLBookError();
}