iOS

On iOS the iframe communicates with the host application through the webkit bridge. Configure a WKWebView with a script-message handler named bridge and decode the JSON string the iframe posts.

Embed and listen

struct WebView: UIViewRepresentable {
  @Binding var path: NavigationPath

  class Coordinator: NSObject, WKNavigationDelegate, WKScriptMessageHandler {
    var webView: WKWebView?
    var onMessageReceived: (Any) -> Void

    required init(onMessageReceived: @escaping (Any) -> Void) {
        self.onMessageReceived = onMessageReceived
        super.init()
    }

    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        self.webView = webView
    }

    // Receive message from WKWebView
    func userContentController(
        _ userContentController: WKUserContentController,
        didReceive message: WKScriptMessage
    ) {
        print(message.body)
        self.onMessageReceived(message.body)
    }
  }

  func onMessageReceived(body: Any) -> Void {
    DispatchQueue.main.async {
      path.append(body as! String)
    }
  }

  func makeCoordinator() -> Coordinator {
    return Coordinator(onMessageReceived: onMessageReceived)
  }

  func makeUIView(context: Context) -> WKWebView {
    let coordinator = makeCoordinator()
    let userContentController = WKUserContentController()
    userContentController.add(coordinator, name: "bridge")

    let configuration = WKWebViewConfiguration()
    configuration.userContentController = userContentController

    let _wkwebview = WKWebView(frame: .zero, configuration: configuration)
    _wkwebview.navigationDelegate = coordinator

    return _wkwebview
  }

  func updateUIView(_ webView: WKWebView, context: Context) {
    let companyIdentifier = AppConfig.companyIdentifier
    let request = URLRequest(url: URL(string: "https://iframe.legit.health/?company=" + companyIdentifier)!)

    webView.load(request)
  }
}

The Coordinator listens for events from the iframe through the bridge message handler. When the iframe posts an event, userContentController(_:didReceive:) fires with the JSON string in message.body; decode it to dispatch on event.message.

See the Callbacks section for the full catalogue.

Next Steps

• Understand each callback type? See the Callbacks section.
• Ready to retrieve the report? See the Output → API Endpoint page.
• Want to display the results? See the Output → User Interface page.