Fast Download Manager

A lightweight and easy-to-use Flutter file downloader with real-time progress tracking, download speed, retry support, cancellation, status callbacks, and multiple simultaneous downloads.

Features

• Download files from a URL
• Real-time download progress
• Download speed tracking
• Download status callbacks
• Unique download IDs
• Cancel individual downloads
• Cancel all active downloads
• Multiple simultaneous downloads
• Automatic retry support
• Configurable retry delay
• Custom HTTP headers
• Overwrite control
• Typed download exceptions
• Null Safety support
• Flutter compatible
• Simple and developer-friendly API

Installation

Add the latest version to your pubspec.yaml:

dependencies:
  fast_download_manager: ^1.2.0

Then run:

flutter pub get

Basic Usage

import 'package:fast_download_manager/fast_download_manager.dart';

final file = await FastDownloader.download(
  url: 'https://example.com/file.pdf',
  savePath: '/storage/emulated/0/Download/file.pdf',
);

print('Downloaded: ${file.path}');

Download Progress

You can receive real-time download progress:

await FastDownloader.download(
  url: 'https://example.com/file.pdf',
  savePath: '/storage/emulated/0/Download/file.pdf',
  onProgress: (progress) {
    print(
      '${(progress.progress * 100).toStringAsFixed(0)}%',
    );

    print(
      'Speed: ${progress.speedFormatted}',
    );

    print(
      '${progress.receivedFormatted} / '
      '${progress.totalFormatted}',
    );
  },
);

The DownloadProgress object provides:

• progress
• received
• total
• speed
• elapsed
• speedInKB
• speedInMB
• speedFormatted
• receivedFormatted
• totalFormatted

Download Status

You can listen to the current download status:

await FastDownloader.download(
  url: fileUrl,
  savePath: filePath,
  onStatus: (status) {
    print(status);
  },
);

Available statuses:

DownloadStatus.downloading
DownloadStatus.retrying
DownloadStatus.completed
DownloadStatus.cancelled
DownloadStatus.failed

Download ID

Every download receives a unique ID.

String? downloadId;

await FastDownloader.download(
  url: fileUrl,
  savePath: filePath,
  onStart: (id) {
    downloadId = id;

    print('Download started: $id');
  },
);

You can also provide your own ID:

await FastDownloader.download(
  url: fileUrl,
  savePath: filePath,
  downloadId: 'my-file-download',
);

Cancel a Download

Cancel a specific download using its ID:

FastDownloader.cancel(downloadId);

For example:

String? downloadId;

FastDownloader.download(
  url: fileUrl,
  savePath: filePath,
  onStart: (id) {
    downloadId = id;
  },
);

if (downloadId != null) {
  FastDownloader.cancel(downloadId!);
}

Cancel All Downloads

Cancel all currently active downloads:

FastDownloader.cancelAll();

You can also check active downloads:

print(
  FastDownloader.activeDownloads,
);

Retry Support

Configure the number of retry attempts:

await FastDownloader.download(
  url: fileUrl,
  savePath: filePath,
  retryCount: 3,
);

You can also configure the retry delay:

await FastDownloader.download(
  url: fileUrl,
  savePath: filePath,
  retryCount: 3,
  retryDelay: const Duration(
    seconds: 2,
  ),
);

The downloader increases the delay between retry attempts.

Custom Headers

You can pass custom HTTP headers:

await FastDownloader.download(
  url: fileUrl,
  savePath: filePath,
  headers: {
    'Authorization': 'Bearer YOUR_TOKEN',
  },
);

Overwrite Control

By default, an existing file will be overwritten: dart await FastDownloader.download( url: fileUrl, savePath: filePath, );

To keep the existing file:

dart await FastDownloader.download( url: fileUrl, savePath: filePath, overwrite: false, );

If the file already exists and overwrite is false, the existing file is returned.

Error Handling

The package provides a typed DownloadException:

dart try { await FastDownloader.download( url: fileUrl, savePath: filePath, ); } on DownloadException catch (e) { print(e.message); print(e.type); }

Available error types:

```dart
DownloadErrorType.network
DownloadErrorType.timeout
DownloadErrorType.server
DownloadErrorType.cancelled
DownloadErrorType.storage
DownloadErrorType.unknown

You can also receive errors through onError:

await FastDownloader.download(
  url: fileUrl,
  savePath: filePath,
  onError: (error) {
    print(error.message);
  },
);

Complete Example

import 'package:fast_download_manager/fast_download_manager.dart';

Future<void> downloadFile() async {
  try {
    final file = await FastDownloader.download(
      url: 'https://example.com/file.pdf',
      savePath: '/storage/emulated/0/Download/file.pdf',
      retryCount: 3,
      retryDelay: const Duration(seconds: 2),

      onStart: (id) {
        print('Download started: $id');
      },

      onProgress: (progress) {
        print(
          'Progress: '
          '${(progress.progress * 100).toStringAsFixed(0)}%',
        );

        print(
          'Speed: ${progress.speedFormatted}',
        );

        print(
          'Downloaded: '
          '${progress.receivedFormatted} / '
          '${progress.totalFormatted}',
        );
      },

      onStatus: (status) {
        print('Status: $status');
      },

      onComplete: (file) {
        print(
          'Download completed: ${file.path}',
        );
      },

      onError: (error) {
        print(
          'Download error: ${error.message}',
        );
      },
    );

    print(
      'File saved at: ${file.path}',
    );
  } on DownloadException catch (e) {
    print(
      'Download failed: ${e.message}',
    );
  }
}

Multiple Downloads

Multiple downloads can run independently.

FastDownloader.download(
  url: fileUrl1,
  savePath: filePath1,
);

FastDownloader.download(
  url: fileUrl2,
  savePath: filePath2,
);

FastDownloader.download(
  url: fileUrl3,
  savePath: filePath3,
);

Each download has its own ID and cancellation token.

Cancel only one download without affecting the others:

FastDownloader.cancel(downloadId);

Version

Current version:

1.2.0

Changelog

1.2.0

• Added unique download IDs
• Added multiple simultaneous downloads
• Added individual download cancellation
• Added cancel all downloads
• Added active download tracking
• Added DownloadProgress model
• Added download speed tracking
• Added formatted download speed
• Added formatted file size
• Added download status callbacks
• Added retry delay support
• Added typed DownloadException
• Added typed download error categories
• Improved error handling
• Improved API structure

1.1.0

• Added download progress callback
• Added download speed callback
• Added retry support
• Added custom headers
• Added overwrite control
• Improved download handling

1.0.0

• Initial release
• Basic file downloading
• Progress tracking
• Null Safety support

License

MIT License