Exporting wallet keys from mobile apps

import UIKit
import WebKit

class ExportWalletViewController: UIViewController, WKScriptMessageHandler {
    var webView: WKWebView!

    func startExport() {
        let urlString = "https://your-domain.com/export"
        guard let url = URL(string: urlString) else { return }

        let config = WKWebViewConfiguration()
        config.userContentController.add(self, name: "exportResult")
        config.websiteDataStore = .nonPersistent()

        webView = WKWebView(frame: view.bounds, configuration: config)
        view.addSubview(webView)
        webView.load(URLRequest(url: url))
    }

    func userContentController(
        _ userContentController: WKUserContentController,
        didReceive message: WKScriptMessage
    ) {
        guard message.name == "exportResult",
              let body = message.body as? String else { return }

        // Parse the result and dismiss the WebView
        webView.removeFromSuperview()
        dismiss(animated: true)
    }
}

import android.annotation.SuppressLint
import android.webkit.JavascriptInterface
import android.webkit.WebView
import android.webkit.WebViewClient
import androidx.appcompat.app.AppCompatActivity

class ExportWalletActivity : AppCompatActivity() {

    private var webView: WebView? = null

    @SuppressLint("SetJavaScriptEnabled")
    fun startExport() {
        val wv = WebView(this).apply {
            settings.javaScriptEnabled = true
            settings.domStorageEnabled = false
            settings.databaseEnabled = false
            webViewClient = WebViewClient()
            addJavascriptInterface(ExportBridge(), "AndroidBridge")
        }

        wv.clearCache(true)
        wv.clearHistory()
        wv.clearFormData()

        webView = wv
        setContentView(wv)
        wv.loadUrl("https://your-domain.com/export")
    }

    inner class ExportBridge {
        @JavascriptInterface
        fun onExportResult(json: String) {
            runOnUiThread {
                webView?.clearCache(true)
                webView?.clearHistory()
                finish()
            }
        }
    }
}

import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:webview_flutter/webview_flutter.dart';

const String exportPageUrl = 'https://your-domain.com/export';

class ExportWalletScreen extends StatefulWidget {
  const ExportWalletScreen({super.key});

  @override
  State<ExportWalletScreen> createState() => _ExportWalletScreenState();
}

class _ExportWalletScreenState extends State<ExportWalletScreen> {
  bool _visible = false;
  WebViewController? _controller;

  void _openExport() {
    _controller = WebViewController()
      ..setJavaScriptMode(JavaScriptMode.unrestricted)
      ..addJavaScriptChannel(
        'exportResult',
        onMessageReceived: (JavaScriptMessage message) {
          _onExportResult(message.message);
        },
      )
      ..loadRequest(Uri.parse(exportPageUrl));
    setState(() => _visible = true);
  }

  void _onExportResult(String jsonString) {
    final data = jsonDecode(jsonString) as Map<String, dynamic>;
    if (data['status'] == 'success' || data['status'] == 'error') {
      setState(() => _visible = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        ElevatedButton(
          onPressed: _openExport,
          child: const Text('Export wallet'),
        ),
        if (_visible && _controller != null)
          Expanded(
            child: WebViewWidget(controller: _controller!),
          ),
      ],
    );
  }
}

func userContentController(
    _ userContentController: WKUserContentController,
    didReceive message: WKScriptMessage
) {
    guard message.name == "exportResult",
          let body = message.body as? String,
          let data = body.data(using: .utf8),
          let result = try? JSONSerialization.jsonObject(with: data) as? [String: Any]
    else { return }

    if result["status"] as? String == "success" {
        // Key export completed successfully. Dismiss the WebView.
    } else {
        // An error occurred during export.
    }

    webView.removeFromSuperview()
    dismiss(animated: true)
}

inner class ExportBridge {
    @JavascriptInterface
    fun onExportResult(json: String) {
        val result = JSONObject(json)

        when (result.getString("status")) {
            "success" -> {
                // Key export completed successfully. Dismiss the activity.
            }
            "error" -> {
                // An error occurred during export.
            }
        }

        runOnUiThread { finish() }
    }
}

void _onExportResult(String jsonString) {
  final data = jsonDecode(jsonString) as Map<String, dynamic>;

  if (data['status'] == 'success') {
    // Key export completed successfully. Dismiss the WebView.
    setState(() => _visible = false);
  } else if (data['status'] == 'error') {
    // An error occurred during export.
    debugPrint('Export failed: ${data['error']}');
    setState(() => _visible = false);
  }
}