downChunk method

Future<ProcessState> downChunk(ProcessState state, int idx, { int retry = 3, })

Implementation

Future<ProcessState> downChunk(ProcessState state, int idx, {int retry = 3}) async {
  Chunk ck = state.chunks[idx];
  for (int attempt = 0; attempt < retry; attempt++) {
    try {
      HttpClient c = HttpClient();
      c.connectionTimeout = const Duration(seconds: 10);
      final req = await c.getUrl(Uri.parse(state.url));
      req.headers.add('Range', 'bytes=${ck.startOffset}-${ck.endOffset - 1}');
      final resp = await req.close();
      if (resp.statusCode >= 200 && resp.statusCode < 300) {
        if (savePath != null) {
          final chunkFile = File(_chunkFilePath(ck.partNumber));
          final sink = chunkFile.openWrite();
          await for (var ls in resp) {
            sink.add(ls);
          }
          await sink.close();
          ck.data = <int>[];
        } else {
          for (var ls in await resp.toList()) {
            ck.data.addAll(ls);
          }
        }
      } else {
        throw DownloadFailureException();
      }
      state.successCount++;
      return state;
    } catch (e) {
      if (attempt == retry - 1) {
        print('Download chunk error (final):$e');
        throw DownloadFailureException();
      } else {
        print('Download chunk error, retrying ($attempt):$e');
        await Future.delayed(const Duration(milliseconds: 500));
      }
    }
  }
  throw DownloadFailureException();
}