fetch static method

Future<bool> fetch({ required String downloadDir, required String filename, void onProgress(int count, int blockSize)?, })

Download a single financial data file.

Implementation

static Future<bool> fetch({
  required String downloadDir,
  required String filename,
  void Function(int count, int blockSize)? onProgress,
}) async {
  final server = gpHosts.first;
  final client = TdxSocketClient();

  try {
    final ok = await client.connect(server.host, server.port);
    if (!ok) return false;

    await client.setup();

    // Download file in chunks
    final filePath = '$downloadDir/$filename';
    final dir = Directory(downloadDir);
    if (!dir.existsSync()) {
      dir.createSync(recursive: true);
    }

    final file = File(filePath);
    final sink = file.openWrite();

    int offset = 0;
    while (true) {
      final chunk = await client.getReportFile(filename, offset);
      if (chunk.isEmpty || chunk.length <= 1) break;

      // First 2 bytes indicate chunk size
      if (chunk.length > 2) {
        final data = Uint8List.view(
            chunk.buffer, chunk.offsetInBytes + 2, chunk.length - 2);

        if (data.isEmpty) break;

        sink.add(data);
        offset += data.length;
        onProgress?.call(offset, 0);
      } else {
        break;
      }
    }

    await sink.flush();
    await sink.close();
    return true;
  } finally {
    client.disconnect();
  }
}