Swift SDK

Introduction

Welcome to the developer documentation for the Kameleoon Swift SDK! Our SDK gives you the possibility of running experiments on native mobile iOS applications. Integrating our SDK into your applications is relatively easy, and its footprint (in terms of memory and network usage) is low.

You can refer to the SDK reference to check out all possible features of the SDK. Also make sure you check out our Getting started tutorial which we have prepared to walk you through the installation and implementation.

Getting started

This guide is designed to help you integrate our SDK in a few minutes and start running experiments in your iOS apps. This tutorial will explain the setup of a simple A/B test to change the number of recommended products based on different variations.

Creating an experiment

First, you must create an experiment in the Kameleoon back-office so that our platform is aware of the new A/B test you're planning to implement on your side. Make sure that server-side type is chosen as shown below:

Server-side experiment

Upon successful creation of the experiment, you will need to get its ID to use in the SDK as an argument to the triggerExperiment() method.

Installing the SDK

Currently the Swift SDK must be manually downloaded.

Swift version 5.1 - ARM & x86_64

To incorporate the SDK into your project, just unzip it and drag it into your project in XCode. Then change the settings of your project to add ssx.framework to both Embedded binaries and Linked Frameworks and Libraries.

Initializing Kameleoon Client

import ssx

public class KameleoonDelegate
{
    private let siteCode = "a8st4f59bj"
    public let kameleoonClient = ClientFactory.create(sitecode: siteCode)
}

After installing the SDK into your application and setting up an server-side experiment on Kameleoon's back-office, the next step is to create the Kameleoon client.

The code on the right gives a clear example. A Client is a singleton object that acts as a bridge between your application and the Kameleoon platform. It includes all the methods and properties you will need to run an experiment.

While executing the ClientFactory.create() method initializes the client, on iOS it is not immediately ready for use. This is because the current configuration of experiments (along with their traffic repartition) has to be retrieved from a Kameleoon remote server. This requires network access, which is not always available. Until the Kameleoon client is fully ready, you should not try to run any other method in our SDK. Note that once the first configuration of experiments is fetched, it is then periodically refreshed, but even if the refresh fails for any reason, the Kameleoon client will still be ready and working (but on an outdated / previous configuration).

We provide the .ready public getter to know if the Kameleoon client initialization completed.

Alternatively, we provide a helper callback to encapsulate logic of experiment triggering and variation implementation. What approach (.ready or callback) is best to use depends on your own preferences and on the exact use case at hand. As a rule of thumb, we recommend using .ready when it is expected that the SDK will indeed be ready for use. For instance, if you are running an experiment on some dialog that would be accessible only after a few seconds / minutes of navigation within the application. And we recommend to use the callback when there is a high probability that the SDK is still in the process of initialization. For instance, an experiment that would take place at the launch of the application would be better treated with a callback that would make the application wait until either the SDK is ready or a specified timeout has expired.

Triggering an experiment

Running an A/B experiment on your iOS application means bucketing your users into several groups (one per variation). The SDK takes care of this bucketing (and the associated reporting) automatically.

Triggering an experiment by calling the triggerExperiment() method will register a random variation for a given userID. If this userID is already associated with a variation (most likely a returning visitor that has already been exposed to the experiment previously), then it will return the previous variation associated with a given experiment.

The triggerExperiment() method will quite often throw out exceptions. You should generally treat an exception as if the user was bucketed into the reference. Two very common cases for throwing exceptions are:

Kameleoon client is not ready yet (discussed in previous section). This results in a KameleoonError.sdkNotReady exception.
The experiment has not yet been launched on the Kameleoon platform (but the code implementing the experiment on the iOS application's side is already deployed). This results in a KameleoonError.experimentConfigurationNotFound exception.

import ssx

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    func applicationWillEnterForeground(_ application: UIApplication) {
        let kameleoonClient = kameleoonDelegate.kameleoonClient
        let userID = "1267576" // usually, this would be the internal ID of this user
        var variationID : VariationID
        var recommendedProductsNumber : Int

        if (kameleoonClient.ready) {
            variationID = try? kameleoonClient.triggerExperiment(userID, 75253) ?? "reference"
        }
        else {
            // The SDK is not ready, so the user is "out of the experiments". This is the same as if he was bucketed into the reference
            variationID = "reference"
        }

        if (variationID == "reference")) {
            //This is the default / reference number of products to display
            recommendedProductsNumber = 5
        }
        else if (variationID == "148382") {
            //We are changing number of recommended products for this variation to 10
            recommendedProductsNumber = 10
        }
        else if (variationID == "187791") {
            //We are changing number of recommended products for this variation to 8
            recommendedProductsNumber = 8
        }
    }
}

We provide two code samples to illustrate the triggering of an experiment. The first one uses the .ready approach. It's a bit simpler.

import ssx

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    func applicationWillEnterForeground(_ application: UIApplication) {
        let kameleoonClient = kameleoonDelegate.kameleoonClient
        let userID = "1267576" // usually, this would be the internal ID of this user
        var variationID : VariationID
        var recommendedProductsNumber : Int
        kameleoonClient.runWhenReady(1000) { success in
            if (success)
            {
                variationID = try? kameleoonClient.triggerExperiment(userID, 75253) ?? "reference"
                if (variationID == "reference")) {
                    //This is the default / reference number of products to display
                    recommendedProductsNumber = 5
                }
                else if (variationID == "148382") {
                    //We are changing number of recommended products for this variation to 10
                    recommendedProductsNumber = 10
                }
                else if (variationID == "187791") {
                    //We are changing number of recommended products for this variation to 8
                    recommendedProductsNumber = 8
                }
            }
            else
            {
                variationID = "reference"
                recommendedProductsNumber = 5
            }
        }
    }
}

This is a second example with the callback runWhenReady() approach. You need to pass a lambda as a second argument, with signature (Bool) -> Void. The boolean that will be passed indicates if the SDK is ready or if the timeout was reached. Note that here we used a timeout of 1000 milliseconds.

Implementing variation code

var recommendedProductsNumber : Int

if (variationID == "reference")) {
    //This is the default / reference number of products to display
    recommendedProductsNumber = 5
}
else if (variationID == "148382") {
    //We are changing number of recommended products for this variation to 10
    recommendedProductsNumber = 10
}
else if (variationID == "187791") {
    //We are changing number of recommended products for this variation to 8
    recommendedProductsNumber = 8
}

To execute different code paths depending on the variation assigned to the visitor, you will need the list of all the experiment's variation IDs. You can find these variation IDs (as well as the experiment ID) by opening the experiment in the back-office interface.

Once you have the IDs of the different variations, you can implement a different action for each variation, and one of the code paths will be executed, based on the associated variationID for the current visitor. Generally, this can be done using a simple if / else or switch mechanism. In our example, we just change the number of recommended products with two different variations.

Get variationID

Tracking conversion

let userID = UUID.randomUUID().toString()
let goalID = "83023"

kameleoonClient.trackConversion(userID : "1267576", goalID : 128763, revenue: 1.0) { success in
    if success {
        // callback code
    }
}

After you are done with triggering an experiment, the next step is usually to start tracking conversions. This is done to measure performance characteristics according to the goals that make sense for your business.

For this purpose, use the trackConversion() method of the SDK as shown in the example. You need to pass the userID and goalID parameters so we can correctly track conversion for this particular user.

Get goalID

Obtaining results

Once your implementation is in place on the mobile app side (experiment triggering, variations handling, and conversion tracking), it is time to launch the experiment on the Kameleoon platform. You do this in the same way as for a front-end test. Basic operations such as starting, pausing and stopping the experiment work exactly in the same way.

After the experiment is launched, first results will be available on our standard results page in the back-office after a duration of 30 minutes. This is because (as is the case with front-end testing) visits are considered over after 30 minutes of inactivity. Inactivity in this context means the absence of calls sent to the Kameleoon back-end servers (such calls are made via triggerExperiment(), trackConversion() or flush() methods).

Reference

This is a full reference documentation of the Swift SDK.

If this is your first time working with the Swift SDK, we strongly recommend you go over our Getting started tutorial to integrate the SDK and start experimenting in a few minutes.

Initialization: creating the Kameleoon Client

let kameleoonClient = ClientFactory.create(sitecode: siteCode)

The starting point for using the SDK is the initialization step. All interaction with the SDK is done through an object named KameleoonClient, therefore you need to create this object.

Arguments

Name	Type	Description
siteCode	String	Code of the website you want to run experiments on. This unique code id can be found in our platform's back-office. This field is mandatory.

Checking that the Kameleoon Client is properly initialized

let ready = kameleoonClient.ready

For mobile SDKs, the initialization of the Kameleoon Client is not immediate, as it needs to perform a server call to retrieve the current configuration for all active experiments. It is recommended to check if the SDK is ready by calling this method before triggering an experiment. Alternatively, you could setup exception catching around the triggerExperiment() method to look for the KameleoonError.sdkNotReady exception, or you could use the runWhenReady() method with a callback as detailed in the next paragraph.

Arguments

Name	Type	Description

Return value

Name	Type	Description
ready	Bool	Boolean representing the status of the SDK (properly initialized, or not yet ready to be used).

Waiting until the Kameleoon Client is initialized

kameleoonClient.runWhenReady(1000) { success in
    if (success)
    {
        variationID = try? kameleoonClient.triggerExperiment(userID, experimentID) ?? "reference"
        if (variationID == "reference")) {
            //This is the default / reference number of products to display
            recommendedProductsNumber = 5
        }
        else if (variationID == "148382") {
            //We are changing number of recommended products for this variation to 10
            recommendedProductsNumber = 10
        }
        else if (variationID == "187791") {
            //We are changing number of recommended products for this variation to 8
            recommendedProductsNumber = 8
        }
    }
    else
    {
        variationID = "reference"
        recommendedProductsNumber = 5
    }
}

For mobile SDKs, the initialization of the Kameleoon Client is not immediate, as it needs to perform a server call to retrieve the current configuration for all active experiments. The runWhenReady() method of the KameleoonClient class allows to pass a callback that will be executed as soon as the SDK is ready for use. It also allows the use of a timeout.

The lambda given as second argument to this method must have signature (Bool) -> Void. The lambda will be called with argument true once the Kameleoon client is ready, and should contain code triggering an experiment and implementing variations. The lambda will be called with argument false if the specified timeout happens before the client is initialized. Usually this case should implement the "reference" variation, as the user will be "out of the experiment" if a timeout takes place.

Arguments

Name	Type	Description
timeout	Int	Timeout (in milliseconds). Two versions of this method exist, with and without this argument. If not provided, it will use the default value of 2000 milliseconds.
callback	(Bool) -> Void	Callback object. This field is mandatory. It is a lambda expression that will get a Bool argument representing whether the Kameleoon Client became ready before the timeout was reached.

Triggering experiments

String userID = UUID.randomUUID().toString()
Int experimentID = 75253
String variationID

variationID = try? kameleoonClient.triggerExperiment(userID, experimentID) ?? "reference"

To trigger an experiment, call the triggerExperiment() method of our SDK.

This method takes userID and experimentID as mandatory arguments to register a variation for a given user.

If such a user has never been associated with any variation, the SDK returns a randomly selected variation. In case a user with a given userID is already registered with a variation, it will detect the previously registered variation and return the variationID.

You have to make sure that proper error handling is set up in your code as shown in the example to the right to catch potential exceptions.

Arguments

Name	Type	Description
userID	String	Unique identifier of the user. This field is mandatory.
experimentID	Int	ID of the experiment you want to expose to a user. This field is mandatory.

Return value

Name	Type	Description
variationID	String	ID of the variation that is registered for the given userID.

Exceptions Thrown

Type	Description
KameleoonError.sdkNotReady	Exception indicating that the SDK has not completed its initialization yet.
KameleoonError.experimentConfigurationNotFound	Exception indicating that the request experiment ID has not been found in the internal configuration of the SDK. This is usually normal and means that the experiment has not yet been started on Kameleoon's side (but code triggering / implementing variations is already deployed on the mobile app's side).

Tracking Conversion

let userID = UUID.randomUUID().toString()
let goalID = "83023"

try? kameleoonClient.addData(userID : userID, data : Interest(2))
try? kameleoonClient.addData(userID : userID, data : Conversion(goalID : 32, revenue : 10.0, negative : false))
try? kameleoonClient.trackConversion(userID : userID, goalID : goalID, revenue: 10.0)

To track conversion, use the trackConversion() method. This method requires userID and goalID to track conversion on this particular goal. In addition, this method requires revenue as a third argument to track revenue. The userID usually is identical to the one that was used when triggering the experiment.

The trackConversion() method doesn't return any value. This method is non-blocking as the server call is made asynchronously.

Arguments

Name	Type	Description
userID	String	Unique identifier of the user. This field is mandatory.
goalID	String	ID of the goal. This field is mandatory.
revenue	Float	Revenue of the conversion. This field is optional.

Saving data

try? kameleoonClient.addData(userID : userID, data : Interest(2))
try? kameleoonClient.addData(userID : userID, data : Conversion(goalID : 32, revenue : 10.0, negative : false))

To associate various data with the current user, we can use the addData() method. This method requires the userID as a first parameter, and then accept several additional parameters. Those additional parameters represent the various Data Types allowed in Kameleoon.

Note that the addData() method doesn't return any value and doesn't interact with the Kameleoon back-end servers by itself. Instead, every data declared is saved for further sending via the flush() method described in the next paragraph. This allows a minimal number of server calls to be made, as data are usually regrouped in a single server call triggered by the execution of flush().

The triggerExperiment() and trackConversion() methods also sends out previously associated data, exactly as the flush() method.

Arguments

Name	Type	Description
userID	String	Unique identifier of the user. This field is mandatory.
data	Data	one or more values conforming to the Data protocol which may be passed separated by a comma.

Data Types

Conversion Data Type

try? kameleoonClient.addData(userID : userID, data : Conversion(goalID : 32, revenue : 10.0, negative : false))

Name	Type	Description
goalID	String	ID of the goal. This field is mandatory.
revenue	Float	Conversion revenue. This field is optional.
negative	Bool	Defines if the revenue is positive or negative. This field is optional.

Custom Data Type

try? kameleoonClient.addData(userID : userID, data : Custom(id : 1, value : "some custom value"))

Name	Type	Description
index	Int	Index / ID of the custom data to be stored. This field is mandatory.
value	String	Value of the custom data to be stored. This field is mandatory.

Interest Data Type

try? kameleoonClient.addData(userID : userID, data : Interest(2))

Name	Type	Description
index	Int	Index of interest. This field is mandatory.

Flushing saved data

let userID = UUID.randomUUID().toString()

try? kameleoonClient.addData(userID : userID, data : Interest(2))
try? kameleoonClient.addData(userID : userID, data : Conversion(goalID : 32, revenue : 10.0, negative : false))
try? kameleoonClient.flush(userID : userID)

Data associated with the current user via addData() method is not sent immediately to the server. It is stored and accumulated until it is sent automatically by the triggerExperiment() or trackConversion() methods, or manually by the flush() method. This allows the developer to exactly control when the data is flushed to our servers. For instance, if you call the addData() method a dozen times, it would be a waste of ressources to send data to the server after each addData() invocation. Just call flush() once at the end.

The flush() method doesn't return any value. This method is non-blocking as the server call is made asynchronously.

Arguments

Name	Type	Description
userID	String	Unique identifier of the user. This field is mandatory.
completionHandler	((Bool) -> Void)?	Callback object. This field is an optional. It is a lambda expression that will asynchronously get called with a Bool argument representing whether the `flush()` call succeeded or not.