A framework for synchronizing files to and from anything.

I'm building and maintaining this package for my open source notetaking app, Saber.

Getting started

There is a bit of setup required for this package due to its abstract nature. You can do all of the following in a single file (e.g. my_syncer.dart) or organize it however you like.

You can view a simple example of this in the example file, or see a real-world example in Saber's saber_syncer.dart, which has added functionality for encryption and caching.

  1. Decide on your local and remote file classes. E.g. Saber uses File for local files and WebDavFile for remote files. I will refer to these as MyLocalFile and MyRemoteFile respectively, but they can be anything you want.

  2. Extend the AbstractSyncFile class to use the correct generic types.

    The AbstractSyncFile class is intended to help you store more information other than just the local and remote files, such as their path on the remote server, so add any additional fields you need.

    class MySyncFile extends AbstractSyncFile<MyLocalFile, MyRemoteFile> {
        required super.remoteFile,
        required super.localFile,
      // Use your IDE to help you implement the necessary methods
  3. Extend the AbstractSyncInterface with the correct generic types.

    The AbstractSyncInterface class is how this package can interact with your local and remote files.

    Your class has to have a const constructor which means you can't use variables that aren't final. However, you can use static variables if you need to save state.

    class MySyncInterface extends AbstractSyncInterface<MySyncFile, MyLocalFile, MyRemoteFile> {
      const MySyncInterface();
      // Use your IDE to help you implement the necessary methods
  4. Finally, we can create a Syncer object.

    The Syncer object is what you will interact with outside of this file.

    final syncer = Syncer<MySyncInterface, MySyncFile, MyLocalFile, MyRemoteFile>(
      const MySyncInterface(),

Usage examples

Add a file to the upload queue

  // Provide any of syncFile, localFile, or remoteFile
  localFile: MyLocalFile(...),

Add a file to the download queue

  // Provide any of syncFile, localFile, or remoteFile
  remoteFile: MyRemoteFile(...),

(The uploader and downloader have an identical interface.)

Check the server for changes (and download them)

await syncer.downloader.refresh();

Monitor the progress of uploads

if (syncer.downloader.isRefreshing) {
  print('Still checking the server for changes');

final subscription = syncer.uploader.transferStream.listen((syncFile) {
  print('Uploaded file: $syncFile');