Download file in Dart/Flutter

download.dart

static var httpClient = new HttpClient();
Future<File> _downloadFile(String url, String filename) async {
  var request = await httpClient.getUrl(Uri.parse(url));
  var response = await request.close();
  var bytes = await consolidateHttpClientResponseBytes(response);
  String dir = (await getApplicationDocumentsDirectory()).path;
  File file = new File('$dir/$filename');
  await file.writeAsBytes(bytes);
  return file;
}

You can use the flutter_web_file_saver package for this:

import 'package:flutter_web_file_saver/flutter_web_file_saver.dart';

await FlutterWebFileSaver.saveText(
  content: csvData,
  filename: 'export.csv',
);

This package:

• ✅ Native browser "Save As" dialog
• ✅ Works offline
• ✅ 25+ methods for different file types
• ✅ No cloud storage needed

Package: https://pub.dev/packages/flutter_web_file_saver