Flutter plugin

This guide provides detailed information about our Flutter plugin which is built on top of our Android SDK and iOS mobile SDKs. The plugin provides you a way to interact with the native SDKs.

All of our SDKs are open source. Go to our Flutter GitHub repository to see the source code.

Language Support

Dart SDK v2.16.2 and greater, and Flutter v2.5.0 and greater.

Initialization

Set up Split in your code base with the following two steps:

1. Add the package in your pubspec.yaml file

dependencies:
  splitio: 0.1.2+2

2. Instantiate the plugin

/// Initialize Split plugin
import 'package:splitio/split_client.dart';
import 'package:splitio/splitio.dart';

final Splitio _split = Splitio('YOUR_API_KEY', 'KEY');

We recommend keeping only one instance of the Splitio object at all times (singleton pattern) and reusing it throughout your application.

Include the API key for the environment that you are setting up the SDK for. The API key is available on your Organization Settings page, on the API keys tab. Select the "Client-side" type. This is a special type of API token with limited privileges to be used on mobile clients. Learn more about API keys.

Using the plugin

Basic use

When the SDK is instantiated, it starts background tasks to update an in-memory cache with small amounts of data fetched from Split servers. This process can take up to a few hundred milliseconds, depending on the size of data. If the SDK is asked to evaluate which treatment to show to a customer for a specific split while it's in this intermediate state, it may not have the data necessary to run the evaluation. In this case, the SDK does not fail, rather, it returns the control treatment.

To make sure the SDK is properly loaded before asking it for a treatment, wait until the SDK is ready, as shown below. You can use the onReady parameter when creating the client to get notified when this happens.

After the observable calls back, you can use the getTreatment method to return the proper treatment based on the SPLIT_NAME and the key variable you passed when instantiating the SDK. Then use an if-else-if block as shown below and insert the code for the different treatments that you defined in the Split web interface. Remember the final else branch in your code to handle the client returning control.

/// Get treatment
_split.client(onReady: (client) async {
  final String treatment = await client.getTreatment('SPLIT_NAME');

  if (treatment == 'on') {
    /// Insert code here to show on treatment
  } else if (treatment == 'off') {
    /// Insert code here to show off treatment
  } else {
    /// Insert your control treatment code here
  }
});

Shutdown

Call the client.destroy() method once you've stopped using the client, as this method gracefully shuts down the Split SDK by stopping all background threads, clearing caches, closing connections, and flushing the remaining unpublished impressions.

/// Initialize Split plugin
final Splitio _split = Splitio('YOUR_API_KEY', 'KEY');
final SplitClient _client = _split.client();

/// You should call destroy() on the client once it is no longer needed:
_client.destroy();

After destroy() is called and finishes, any subsequent invocations to getTreatment/getTreatments or manager methods result in control or empty list, respectively.

Multiple evaluations at once

In some instances, you may want to evaluate treatments for multiple splits at once. Use the client.getTreatments method to do this. Simply pass a list of the split names you want treatments for and the method returns a map with the results.

const splitNames = ['SPLIT_NAME_1', 'SPLIT_NAME_2'];
var treatments = {};

_split.client(onReady: (client) async {
  treatments = await client.getTreatments(splitNames);
});

Attribute syntax

To target based on custom attributes, pass the client's getTreatment method as an attribute map at runtime.

In the example below, we are rolling out a split to users. The provided attributes plan_type, registered_date, permissions, and deal_size are passed to the getTreatment call. These attributes are compared and evaluated against the attributes used in the rollout plan as defined in the Split Web console to decide whether to show the on or off treatment to this account. The getTreatment method supports five types of attributes: strings, numbers, dates, booleans, and sets. The proper data type and syntax for each are:

• Strings: Use type String.
• Numbers: Use type num (int or double).
• Dates: Express the value in milliseconds since epoch.
  Note: Milliseconds since epoch is expressed in UTC. If your date or date-time combination is in a different timezone, first convert it to UTC, then transform it to milliseconds since epoch.
• Booleans: Use type bool.
• Sets: Use type List or Set.

final attributes = {
  // date attributes are handled as `millis since epoch`
  'registered_date': DateTime.now().millisecondsSinceEpoch,
  // this string will be compared against a list called `plan_type` or against another string
  'plan_type': 'growth',
  // this number will be compared against a number value called `deal_size`
  'deal_size': 10000,
  // this array will be compared against a set called `permissions`
  'permissions': ['read', 'write']
};

final String treatment =
    await _client.getTreatment('SPLIT_NAME', attributes);

if (treatment == 'on') {
  // insert on code here
} else if (treatment == 'off') {
  // insert off code here
} else {
  // insert control code here
}

You can pass your attributes in this way to the getTreatments method.

Track

Use the track method to record any actions your customers perform. Each action is known as an event and corresponds to an event type. Calling track through one of our SDKs or via the API is the first step to getting experimentation data into Split and allows you to measure the impact of your splits on your users' actions and metrics. Learn more about using track events in Split.

In the examples below, you can see that the .track() method can take up to four arguments. The proper data type and syntax for each are:

• EVENT_TYPE: The event type that this event should correspond to. The expected data type is String. Full requirements on this argument are:
  • Contains 63 characters or fewer.
  • Starts with a letter or number.
  • Contains only letters, numbers, hyphen, underscore, or period.
  • This is the regular expression we use to validate the value: [a-zA-Z0-9][-_\.a-zA-Z0-9]{0,62}
• TRAFFIC_TYPE: (Optional) The traffic type of the key in the track call. The expected data type is String. You can only pass values that match the names of traffic types that you have defined in your instance of Split.
• VALUE: (Optional) The value is used to create the metric. The expected data type is double.
• PROPERTIES: (Optional) An object of key value pairs that can be used to filter your metrics. Learn more about event property capture. Split currently supports three types of properties: strings, numbers, and booleans.

The track method returns a boolean value of true or false to indicate whether or not the client was able to successfully queue the event to be sent back to Split's servers on the next event post. The service returns false if the current queue size is equal to the config set by eventsQueueSize or if an incorrect input to the track method is provided.

In the case that a bad input is provided, you can read more about our SDK's expected behavior.

_split.client(onReady: (client) async {
  /// Named parameters are optional
  client.track('EVENT_TYPE',
      trafficType: 'TRAFFIC_TYPE',
      value: 120.25,
      properties: {'package': 'premium', 'admin': true, 'discount': 50});
});

Configuration

The SDK has a number of knobs for configuring performance. Each knob is tuned to a reasonable default. However, you can override values when instantiating the Splitio:

final SplitConfiguration configurationOptions = SplitConfiguration(
  trafficType: 'user',
  enableDebug: true,
  persistentAttributesEnabled: true);

final Splitio _split =
  Splitio('YOUR_API_KEY', 'KEY', configuration: configurationOptions);

The parameters available for configuration are shown below.

Advanced use cases

This section describes advanced use cases and features provided by the SDK.

Instantiate multiple SDK clients

Split supports the ability to release based on multiple traffic types. For example, with traffic types, you can release to users in one split and accounts in another. If you are unfamiliar with using multiple traffic types, refer to the Traffic type guide for more information.

Each SDK client is tied to one specific customer ID at a time, so if you need to roll out splits by different keys, instantiate multiple SDK clients, one for each traffic type. For example, you may want to roll out the feature USER_POLL by users and the feature ACCOUNT_PERMISSIONING by accounts. You can do this with the example below:

final Splitio _split = Splitio('YOUR_API_KEY', 'ACCOUNT_ID');

/// Create a client for the default key, in this case, the account id.
final SplitClient _accountClient = _split.client(onReady: (client) async {
  var userPollTreatment = client.getTreatment('USER_POLL');
});

/// To create another client for a user instead, just pass in a
/// User ID to the splitService.initClient() method. (This is only valid after
/// at least one client has been initialized).
final SplitClient _userClient = _split.client(
    matchingKey: 'USER_ID',
    onReady: (client) async {
      var accountPermissioningTreatment =
          client.getTreatment('ACCOUNT_PERMISSIONING');
    });

/// Track events for accounts
_userClient.track('PAGELOAD', value: 7.86);

/// Track events for users
_accountClient.track('ACCOUNT_CREATED');

Manager

Use these methods on Splitio instance to get a list of the Splits available to the Split client.

/// Retrieves the splits that are currently registered with the SDK.
Future<List<SplitView>> splits()

/// Returns the splits registered with the SDK of this name.
Future<SplitView?> split(String splitName)

/// Returns the names of splits registered with the SDK.
Future<List<String>> splitNames()

Subscribe to events and changes

You can subscribe specify up to four different callbacks when creating a client:

• onReady - The SDK is ready to be used and has the most up-to-date snapshot of your splits.
• onReadyFromCache - The SDK is ready to evaluate using locally cached data (which might be stale). If conditions are met, this event is emitted almost immediately since access to the cache is very fast. Otherwise it won't fire.
• onUpdate - This event fires whenever a split or segment is changed. Use this if you want to reload your app every time you make a change in the Split Web console.
• onTimeout - This event fires when the time set for timeout in the configuration has elapsed and the SDK has not fully loaded.

final Splitio _split = Splitio('YOUR_API_KEY', 'ACCOUNT_ID');

_split.client(onReady: (client) {
  /// Client has fetched the most up-to-date definitions.
}, onReadyFromCache: (client) {
  /// Fired after the SDK could confirm the presence of the Split data.
  /// This event fires really quickly, since there's no actual fetching of information.
  /// Keep in mind that data might be stale, this is NOT a replacement of sdkReady.
}, onUpdated: (client) {
  /// Fired each time the client state changes, for example,
  /// when a Split or a Segment changes.
}, onTimeout: (client) {
  /// Fired if the client was not able to be ready.
  /// GetTreatment can still be called but the result may be CONTROL.
});

You can also receive Futures (or a Stream, for the Update event) by accessing the following methods in the client.

_client.whenReady().then((client) {
  /// Client has fetched the most up-to-date definitions.
});

_client.whenReadyFromCache((client) {
  /// Fired after the SDK could confirm the presence of the Split data.
  /// This event fires really quickly, since there's no actual fetching of information.
  /// Keep in mind that data might be stale, this is NOT a replacement of sdkReady.
});

StreamSubscription<SplitClient> streamSubscription = _client.whenUpdated().listen((client) {
  /// Fired each time the client state changes, for example,
  /// when a Split or a Segment changes.
});

_client.whenTimeout().then((client) {
  /// Fired if the client was not able to be ready.
  /// GetTreatment can still be called but the result may be CONTROL.
});

Link with native factory

A native Split Factory instance can be shared with the plugin to save resources when evaluations need to be performed on native platform logic. To do so, do the following:

Android

1. If not created already, create a subclass of Android's Application, and add its name to the Manifest.

public class CustomApplication extends Application {

}

   <application
        android:label="my_app"
        android:name=".CustomApplication"
        android:icon="@mipmap/ic_launcher">

2. Add the Split Android SDK dependency to your project's build.gradle file.

dependencies {
    implementation 'io.split.client:android-client:split_version'
    ...
}

3. Create a property in your subclass of Application to hold your factory instance.
4. Initialize the factory in the onCreate callback of your Application subclass.

public class CustomApplication extends Application {
    private SplitFactory factory;

    @Override
    public void onCreate() {
        super.onCreate();

        try {
            factory = SplitFactoryBuilder
                .build("YOUR_API_KEY",
                    new Key("USER_KEY"),
                    SplitClientConfig.builder()
                        .build(),
                    getApplicationContext());
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

5. Make the Application subclass implement the SplitFactoryProvider interface, and return the previously created factory in the overridden getSplitFactory() method.

public class CustomApplication extends Application implements SplitFactoryProvider {
    private SplitFactory factory;

    @Override
    public void onCreate() {
        ...
    }

    @Override
    public SplitFactory getSplitFactory() {
        return factory;
    }
}

iOS

1. Add the Split iOS SDK dependency to your app's Podfile.

  pod 'Split', '~> 2.15.0'
...

2. Add a property in your AppDelegate class to hold the factory instance. Make sure to import Split.

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {

  private var splitFactory: SplitFactory?

  ...
}

3. Initialize the factory just before the GeneratedPluginRegistrant.register(with: self) line.

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {

  private var splitFactory: SplitFactory?

  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    let config = SplitClientConfig()
    splitFactory = DefaultSplitFactoryBuilder()
            .setConfig(config)
            .setApiKey("YOUR_API_KEY")
            .setKey(Key(matchingKey: "USER_KEY"))
            .build()
    GeneratedPluginRegistrant.register(with: self)
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }

  ...
}

4. Implement the SplitFactoryProvider protocol in your AppDelegate and return the previously created factory in the overridden getFactory() method.

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate, SplitFactorProvider {

  private var splitFactory: SplitFactory?

  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    ...
  }

  func getFactory() -> SplitFactory? {
    splitFactory
  }
}