feat(app-check): support tokenChanged listener on Android and iOS (#855)

* feat(app-check): support tokenChanged

Add support on Android.

* feat(app-check): support tokenChanged

Add support on iOS.

* feat(app-check): support tokenChanged

Generate changeset.

Author: ebarooni

.changeset/tiny-walls-join.md

@@ -0,0 +1,5 @@
+---
+'@capacitor-firebase/app-check': minor
+---
+
+feat: implement support for `tokenChanged` listener on Android and iOS

packages/app-check/README.md

@@ -160,8 +160,6 @@ addListener(eventName: 'tokenChanged', listenerFunc: TokenChangedListener) => Pr
 
 Called when the App Check token changed.
 
-Only available for Web.
-
 | Param              | Type                                                                  |
 | ------------------ | --------------------------------------------------------------------- |
 | **`eventName`**    | <code>'tokenChanged'</code>                                           |

packages/app-check/android/src/main/java/io/capawesome/capacitorjs/plugins/firebase/appcheck/FirebaseAppCheck.java

@@ -1,11 +1,25 @@
 package io.capawesome.capacitorjs.plugins.firebase.appcheck;
 
 import android.util.Log;
+import androidx.annotation.NonNull;
+import com.google.firebase.appcheck.FirebaseAppCheck.AppCheckListener;
 import com.google.firebase.appcheck.debug.DebugAppCheckProviderFactory;
 import com.google.firebase.appcheck.playintegrity.PlayIntegrityAppCheckProviderFactory;
 
 public class FirebaseAppCheck {
 
+    @NonNull
+    private final FirebaseAppCheckPlugin plugin;
+
+    @NonNull
+    private final AppCheckListener appCheckListener;
+
+    public FirebaseAppCheck(@NonNull FirebaseAppCheckPlugin plugin) {
+        this.plugin = plugin;
+        this.appCheckListener = this.plugin::handleTokenChanged;
+        getFirebaseAppCheckInstance().addAppCheckListener(appCheckListener);
+    }
+
     public void getToken(boolean forceRefresh, final GetTokenResultCallback resultCallback) {
         getFirebaseAppCheckInstance()
             .getAppCheckToken(forceRefresh)

packages/app-check/android/src/main/java/io/capawesome/capacitorjs/plugins/firebase/appcheck/FirebaseAppCheckPlugin.java

@@ -6,14 +6,16 @@
 import com.getcapacitor.PluginCall;
 import com.getcapacitor.PluginMethod;
 import com.getcapacitor.annotation.CapacitorPlugin;
+import com.google.firebase.appcheck.AppCheckToken;
 
 @CapacitorPlugin(name = "FirebaseAppCheck")
 public class FirebaseAppCheckPlugin extends Plugin {
 
     public static final String TAG = "FirebaseAppCheck";
     public static final String ERROR_ENABLED_MISSING = "enabled must be provided.";
+    public static final String TOKEN_CHANGED_EVENT = "tokenChanged";
 
-    private FirebaseAppCheck implementation = new FirebaseAppCheck();
+    private final FirebaseAppCheck implementation = new FirebaseAppCheck(this);
 
     @PluginMethod
     public void getToken(PluginCall call) {
@@ -84,4 +86,10 @@ public void setTokenAutoRefreshEnabled(PluginCall call) {
             call.reject(exception.getMessage());
         }
     }
+
+    public void handleTokenChanged(AppCheckToken token) {
+        JSObject result = new JSObject();
+        result.put("token", token.getToken());
+        notifyListeners(TOKEN_CHANGED_EVENT, result, true);
+    }
 }

packages/app-check/ios/Plugin/FirebaseAppCheck.swift

@@ -4,10 +4,18 @@ import FirebaseCore
 import FirebaseAppCheck
 
 @objc public class FirebaseAppCheck: NSObject {
-    override init() {
+    private let plugin: FirebaseAppCheckPlugin
+
+    public init(plugin: FirebaseAppCheckPlugin) {
+        self.plugin = plugin
+
+        super.init()
+
         if FirebaseApp.app() == nil {
             FirebaseApp.configure()
         }
+
+        NotificationCenter.default.addObserver(self, selector: #selector(self.plugin.handleTokenChanged(_:)), name: Notification.Name.AppCheckTokenDidChange, object: nil)
     }
 
     @objc public func getToken(forceRefresh: Bool, completion: @escaping (String?, Int, Error?) -> Void) {

packages/app-check/ios/Plugin/FirebaseAppCheckPlugin.swift

@@ -1,5 +1,6 @@
 import Foundation
 import Capacitor
+import FirebaseAppCheck
 
 /**
  * Please read the Capacitor iOS Plugin Development Guide
@@ -17,10 +18,11 @@ public class FirebaseAppCheckPlugin: CAPPlugin, CAPBridgedPlugin {
     public let tag = "FirebaseApp"
     public let errorEnabledMissing = "enabled must be provided."
     public let errorGetTokenFailed = "Failed to get token."
+    public let tokenChangedEvent = "tokenChanged"
     private var implementation: FirebaseAppCheck?
 
     override public func load() {
-        implementation = FirebaseAppCheck()
+        implementation = FirebaseAppCheck(plugin: self)
     }
 
     @objc func getToken(_ call: CAPPluginCall) {
@@ -68,4 +70,16 @@ public class FirebaseAppCheckPlugin: CAPPlugin, CAPBridgedPlugin {
         implementation?.setTokenAutoRefreshEnabled(enabled)
         call.resolve()
     }
+
+    @objc func handleTokenChanged(_ notification: Notification) {
+        guard let userInfo = notification.userInfo else {
+            return
+        }
+
+        let token = userInfo[AppCheckTokenNotificationKey] as? String
+
+        var result = JSObject()
+        result["token"] = token ?? NSNull()
+        notifyListeners(tokenChangedEvent, data: result, retainUntilConsumed: true)
+    }
 }

packages/app-check/src/definitions.ts

@@ -25,8 +25,6 @@ export interface FirebaseAppCheckPlugin {
   /**
    * Called when the App Check token changed.
    *
-   * Only available for Web.
-   *
    * @since 1.3.0
    */
   addListener(