iOS

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Overview

The Knot Link SDK provides a seamless way for end users to link their merchant accounts to your iOS app, serving as the foundation for Knot’s merchant connectivity platform. It is a client-side integration, consisting of initializing & configuring the SDK and handling events.

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Installation

The Knot SDK can be installed using CocoaPods or Swift Package Manager (SPM).

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Using CocoaPods

pod init

pod 'KnotSDK'

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Using Swift Package Manager (SPM)

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Initialization

Your backend will create a session by calling Create Session and provide it to your frontend. To start a Knot session, you must first configure the session with a KnotConfiguration class. The configuration allows you to set the environment, product type, entry point, and other user experience configurations.

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Configure the session

The KnotConfiguration and CustomerConfiguration classes are used to initialize the SDK with specific parameters.

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KnotConfiguration

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CustomerConfiguration

See the following real example for how the parameters are used together in text inside the Knot SDK: "Your [customerName] [cardName | Card] was added."

let customerConfiguration = CustomerConfiguration(
    cardName: "Card Name",		    // Your cardName
    customerName: "Customer Name",  // Your customerName
    logoId: "LogoId"				// Your logoID
)

let config = KnotConfiguration(
    sessionId: "session_12345",     // Current session ID
    clientId: "client_67890",       // Your client ID
    environment: .production,       // 'development' | 'production'
    product: .card_switcher,        // 'card_switcher' | 'transaction_link'
    merchantIds: [52],              // Recommend 0 or 1 merchant IDs
    useCategories: true,            // Recommend true
    useSearch: true,                // Recommend true
    domainUrls: nil,                // Explicitly passing nil
    entryPoint: "onboarding",       // Defined by you
    customerConfiguration: customerConfiguration
)

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Open the session

To begin the flow, use the open method with a KnotConfiguration instance and an optional KnotEventDelegate.

Knot.open(configuration: myConfiguration, delegate: self)

let customerConfiguration = CustomerConfiguration(
    cardName: "Card Name",		   
    customerName: "Customer Name",
    logoId: "LogoId"	
)

let config = KnotConfiguration(
    sessionId: "session_12345",
    clientId: "client_67890",
    environment: .development,
    entryPoint: "onboarding",
    product: .cardSwitcher,
    useCategories: true,
    useSearch: true,
    merchantIds: [52]
	customerConfiguration: customerConfiguration
)

Knot.open(configuration: config, delegate: self)

class MyViewController : UIViewController {

  func configureKnot() {
    let controller = Knot.createKnotViewController(configuration: session, delegate: delegate)
    view.addSubview(controller.view)
    addChild(controller)
  }

  ...
}

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Single Merchant Flow

If you decide to use List Merchants to retrieve a list of merchants, list them in your app, and then open the SDK with a single merchant, you can do so by passing a merchant ID when configuring the session in the KnotConfiguration. More in Retrieving & Listing Merchants. The merchant ID is the same across all environments.

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Entry Points

In your app’s user experience, you may choose to integrate Knot in one or multiple places (e.g. from different tabs or screens). How users behave when interacting with Knot from each of these “entry points” may vary and it will be useful for you to be able to differentiate these groups of users by entry point in order to assess the value of each entry point.

You can provide a value for the entry point in when configuring the session in the KnotConfiguration. This value will be returned in the AUTHENTICATED webhook.

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Categories & Search

Users are presented with a list of merchants in the SDK (unless you provide a single merchant as described above). Accompanying the list is a set of categories and a search experience. Each of these components is visible to users by default (as set in Knot’s backend).

You can choose to remove either of them by setting useCategories: false and useSearch: false in KnotConfiguration. This is not recommended.

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Events

To receive updates from the SDK, implement KnotEventDelegate in your class.

class MyViewController: UIViewController, KnotEventDelegate {
    func onSuccess(merchant: String) {
        print("Merchant \(merchant) successfully authenticated.")
    }

    func onError(error: KnotError) {
        print("Error occurred: \(error.errorDescription)")
    }

    func onEvent(event: KnotEvent) {
        print("Received event: \(event.event)")
    }

    func onExit() {
        print("Knot session exited.")
    }
}

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onSuccess

This event is called when a user successfully logged in to the merchant and their card was switched. It takes a single string argument containing the name of the merchant.

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onError

This event is called when an error occurs during SDK initialization and emits a KnotError enum with 4 possible cases, as described below.

func onError(error: KnotError) {
    switch error {
    case .invalidSession:
        print("Error: \(error.errorDescription)")
    case .expiredSession:
        print("Error: \(error.errorDescription)")
    case .invalidClientId:
        print("Error: \(error.errorDescription)")
    case .internalError:
        print("Error: \(error.errorDescription)")
	case .merchantIdNotFound:
        print("Error: \(error.errorDescription)")
	case .invalidCardName:
        print("Error: \(error.errorDescription)")
	case .invalidCustomerName:
        print("Error: \(error.errorDescription)")
	case .invalidLogoId:
        print("Error: \(error.errorDescription)")
    }
}

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onExit

This event is called when a user closes the SDK.

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onEvent

This event is called when certain events occur in the SDK. With this callback, you will be able to understand how a user is progressing through their lifecycle of authenticating to a merchant. It emits a KnotEvent class as described below.

/// Represents a Knot event received during user interaction within the Knot SDK.
@objc public class KnotEvent {

    /// The environment the event emitted from
    @objc public let evironment: Environment
    
    /// The product the event emitted from
    @objc public let product: Product
    
    /// The primary event code.
    @objc public let event: String
    
    /// The merchant associated with the event (if applicable).
    @objc public let merchant: String?

	/// The merchant ID associated with the event (if applicable).
    @objc public let merchantId: String?
    
    /// Additional metadata related to the event, stored as an Objective-C compatible dictionary.
    @objc public let metaData: NSDictionary
    
    /// The identifier associated with this event.
    @objc public let taskId: String?
    
...
}

The following list contains all possible events emitted in the KnotEvent.event property.

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Other Options

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Get current SDK version

If you need to retrieve the current SDK version for your own use case, implement the following:

let sdkVersion = Knot.SDKVersion()
print("Knot SDK Version: \(sdkVersion ?? "Unknown")")

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Close the SDK

If you need to explicitly close the SDK, use the below method, otherwise end users will naturally close the SDK as they interact with the interface.

Knot.close()