Piano SDK for Flutter

Installation

Add the dependency to your pubspec.yaml:

dependencies:
  piano_common: ^1.0.4

Getting Started

Initialize the SDK with your Application ID (AID) and an endpoint:

import 'package:piano_common/piano_common.dart';

final piano = await Piano.init(
  endpoint: PianoEndpoint.production,
  aid: '<AID>',
);

Endpoints

Use one of the predefined regional endpoints or define a custom one:

// Predefined endpoints
PianoEndpoint.production          // Global
PianoEndpoint.productionEurope    // EU
PianoEndpoint.productionAustralia // Australia
PianoEndpoint.productionAsiaPacific // Asia-Pacific
PianoEndpoint.sandbox             // Sandbox

// Custom endpoint
final custom = PianoEndpoint(
  api: 'https://api.piano.io',
  composer: 'https://c2.piano.io',
  id: 'https://id.piano.io',
);

// Single-URL endpoint (all services on the same host)
final local = PianoEndpoint.fromUrl('http://localhost:8080');

Several Instances

An application reporting to more than one Piano account runs an instance per account, and names each of them with id:

final news = await Piano.init(
  endpoint: PianoEndpoint.production,
  aid: '<NEWS_AID>',
  id: 'news',
);

final sports = await Piano.init(
  endpoint: PianoEndpoint.production,
  aid: '<SPORTS_AID>',
  id: 'sports',
);

The identifier is what tells the instances apart, so the modules of an instance key what they open by it — the event storage of piano_cxense, for example, is named after it. An instance therefore finds what its previous launch left behind as long as it is created with the same identifier, which makes an identifier worth keeping stable across releases.

Piano.init accepts an identifier only once as long as the instance carrying it was not closed, and reports an ArgumentError otherwise; it also rejects an empty one. Piano.close frees the identifier again, and so does an initialization that failed — nothing holds the identifier of an instance that was never returned.

An application that names no identifier gets default, which is the single instance case. piano.client.id reports what an instance carries.

Modules

Optional Piano SDKs are added as modules: pass the configuration of each one to Piano.init and reach the module it creates through the extension its package adds to Piano. The modules of an instance are held by piano.client.modules, and Piano.close releases them.

import 'package:piano_cxense/piano_cxense.dart';

final piano = await Piano.init(
  endpoint: PianoEndpoint.production,
  aid: '<AID>',
  configurations: [PianoCxenseConfiguration()],
);

// Added by piano_cxense; throws a StateError without its configuration.
final cxense = piano.cxense;

await piano.close();

Passing more than one configuration for the same module throws an ArgumentError, because which of them would apply would otherwise depend on their order.

A module may need to open a storage or read the platform before it can work, so Piano.init awaits the creation of every module before it returns the instance. A module that fails to be created reports its error from Piano.init, after the modules created before it were closed again — the instance holding them is never returned, so nothing else would release them.

See piano_consents_flutter.

Optionally pass a PianoConsentConfiguration to control consent behavior:

import 'package:piano_consents_flutter/piano_consents_flutter.dart';

final piano = await Piano.init(
  endpoint: PianoEndpoint.production,
  aid: '<AID>',
  consentConfig: PianoConsentConfiguration(),
);

Localization

Pass a language code to localize Piano content. It defaults to en_US:

final piano = await Piano.init(
  endpoint: PianoEndpoint.production,
  aid: '<AID>',
  language: 'fr_FR',
);

The value is available to all Piano services through piano.client.language.

Logging

Enable debug logging by providing a Logger instance:

import 'package:logger/logger.dart';

final piano = await Piano.init(
  endpoint: PianoEndpoint.sandbox,
  aid: '<AID>',
  logger: Logger(),
);

Libraries

piano_common