etebase #

Dart client library for etebase using FFI bindings with libetebase

Table of contents #

• Features
• Installation
• Usage
  • Initialization and Termination
  • General API usage
  • Disposing and cleanup
• Documentation

Table of contents generated with markdown-toc

Features #

• A dart API that mirrors the official Rust API (as seen on https://docs.etebase.com/)
• Internally uses dart FFI to invoke the official C API (https://github.com/etesync/libetebase)
• Supports all features that are supported by the C API

Installation #

Simply add etebase to your pubspec.yaml and run dart pub get (or flutter pub get).

dart pub add etebase

Note: Flutter users should use the etebase_flutter package instead.

Usage #

Initialization and Termination #

The part that is special about the dart API is the fact that all etebase operations run within a custom isolate. This is due to the fact that these operations include network and file I/O, which otherwise would block the main isolate. Thus, you need to initialize the isolate once in order to make it available for the rest of the application.

In addition, that isolate needs to load the native [lib]etebase.[so|dll|dylib] to invoke the native C APIs. As these library can be located anywhere, depending on your platform and configuration, you need to supply a load method to load it.

Finally, that isolate needs to be stopped when your application is done. This is required, as the main isolate of your application will not terminate until the etebase isolate has been terminated as well. Typically, this is done as the "last step" of your application tear down.

To simplify the usage of the API, the isolate handling is done automatically by the EtebaseClient class. When you create a new instance and no isolate is running yet, it is created. When the last client gets disposed, the isolate also gets terminated.

For example, if we assume we are running a Linux machine with the C library installed to /usr/lib/libetebase.so and the main will wait for all operations to be executed. The code to initialize and later terminate the library would look like this:

import 'dart:ffi';

import 'package:etebase/etebase.dart';

// must be a global or static method
DynamicLibrary _loadLibEtebase() {
  return DynamicLibrary.open('/usr/lib/libetebase.so');
}

Future<void> main() async {
  Etebase.ensureInitialized(_loadLibEtebase);

  final client = await EtebaseClient.create('my-client'); // uses default server
  try {
    // your code that uses the library
  } finally {
    await client.dispose();
  }
}

Important: After the client has been disposed, you must not use any managers, collections, items, etc. that belong to it. Make sure this is the last operation in your code.

General API usage #

Once you have initialized the isolate, you can easily use the API in almost the same way as the rust API. Go to https://docs.etebase.com/ to get start. If we for example take the sample rust code from the signup guide, in dart it would look as follows:

import "package:etebase/etebase.dart";

// ...

final user = EtebaseUser(username: "username", email: "[email protected]");
final client = await EtebaseClient.create(..., serverUrl);
final etebase = await EtebaseAccount.signup(client, user, "password");

// ...
await client.dispose();

Disposing and cleanup #

By default, the only thing that needs to be disposed of is the EtebaseClient. It is required to be disposed as otherwise the background isolate will never terminate.

Most other classes do have dispose methods, but they are optional. They all use automated finalizers that release the native resources as soon as they get garbage collected. However, if you want to make sure an instance gets cleaned up, you can manually invoke the dispose method.

Also, since the attached native resources are not known by the garbage collector, your application might consume more memory than desired when not disposing manually. Decide yourself, how memory critical your environment and whether you should or should not dispose the instances.

Documentation #

The documentation is available at https://pub-web.flutter-io.cn/documentation/etebase/latest/. A basic example can be found at https://pub-web.flutter-io.cn/packages/etebase/example.

In addition to that, you can and should refer to the official Etebase Documentation. As the API tries to recreate the Rust-API as closely as possible, you can refer to the Rust examples in that documentation. Most of the samples there can be easily applied to the dart code.

If you intend on using the low-level C API directly, you can do so as well by importing package:etebase/etebase.ffi.dart. In that case, you can follow the documentation of the C api in the docs mentioned above.