Flutter 's Webview - How to clear session status?

Managing WebView session state in Flutter is a common requirement, especially when you need to clear all session information upon user logout or under privacy settings that mandate it. Flutter implements WebView functionality using the webview_flutter plugin, and clearing session state can be achieved through several methods.

1. Using WebView Controller

In the webview_flutter plugin, the WebViewController provides the clearCache() method, which helps clear cached web data. However, this does not always fully clear session data, as sessions may still depend on cookies.

dart
final Completer<WebViewController> _controller = Completer<WebViewController>();

WebView(
  initialUrl: 'https://example.com',
  onWebViewCreated: (WebViewController webViewController) {
    _controller.complete(webViewController);
  },
);

// Clear cache
void clearWebViewCache() async {
  final controller = await _controller.future;
  controller.clearCache();
}

2. Clearing Cookies

Clearing cookies is another critical aspect of managing Web sessions. We can use the cookie_manager plugin to clear cookies within the WebView.

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

void clearCookies() async {
  final cookieManager = CookieManager();

  // Clear all cookies in the WebView
  await cookieManager.clearCookies();
}

Integrating this method with page exit or session termination logic effectively ensures complete session clearance.

3. Reloading WebView

Sometimes, simply reloading the WebView can reset session state, particularly after clearing cache and cookies.

dart
final controller = await _controller.future;
controller.reload();

Summary

In Flutter, combining the webview_flutter plugin with the cookie_manager plugin enables effective management and clearing of WebView session state. This is especially important for applications handling sensitive data and user privacy, such as online banking or medical apps. By appropriately utilizing these methods, user data can be effectively protected from leaks.

In one of my projects, we needed to provide a clean session environment for users upon each login to prevent residual information from previous users. By combining clearCache() and clearCookies() methods, and calling reload() at appropriate times, we successfully met this requirement, enhancing the application's security and user trust.