Initialize App Check debug mode in initializeAppCheck

packages/app-check/src/api.test.ts

@@ -16,7 +16,7 @@
  */
 import '../test/setup';
 import { expect } from 'chai';
-import { spy, stub } from 'sinon';
+import { match, spy, stub } from 'sinon';
 import {
   setTokenAutoRefreshEnabled,
   initializeAppCheck,
@@ -38,10 +38,12 @@ import * as logger from './logger';
 import * as client from './client';
 import * as storage from './storage';
 import * as internalApi from './internal-api';
+import * as indexeddb from './indexeddb';
 import { deleteApp, FirebaseApp } from '@firebase/app';
 import { CustomProvider, ReCaptchaV3Provider } from './providers';
 import { AppCheckService } from './factory';
 import { AppCheckToken } from './public-types';
+import { getDebugToken } from './debug';
 
 describe('api', () => {
   let app: FirebaseApp;
@@ -118,6 +120,41 @@ describe('api', () => {
         })
       ).to.equal(appCheckInstance);
     });
+    it('starts debug mode on first call', async () => {
+      const fakeWrite = (): Promise<void> => Promise.resolve();
+      const writeToIndexedDBStub = stub(
+        indexeddb,
+        'writeDebugTokenToIndexedDB'
+      ).callsFake(fakeWrite);
+      stub(indexeddb, 'readDebugTokenFromIndexedDB').callsFake(() =>
+        Promise.resolve(undefined)
+      );
+      const logStub = stub(logger.logger, 'warn');
+      const consoleStub = stub(console, 'log');
+      self.FIREBASE_APPCHECK_DEBUG_TOKEN = true;
+      initializeAppCheck(app, {
+        provider: new ReCaptchaV3Provider(FAKE_SITE_KEY)
+      });
+      await fakeWrite();
+      const token = writeToIndexedDBStub.args[0];
+      expect(logStub).to.not.be.called;
+      expect(consoleStub.args[0][0]).to.include(token);
+      self.FIREBASE_APPCHECK_DEBUG_TOKEN = undefined;
+    });
+    it('warns about debug mode on second call', async () => {
+      const logStub = stub(logger.logger, 'warn');
+      self.FIREBASE_APPCHECK_DEBUG_TOKEN = 'abcdefg';
+      initializeAppCheck(app, {
+        provider: new ReCaptchaV3Provider(FAKE_SITE_KEY)
+      });
+      initializeAppCheck(app, {
+        provider: new ReCaptchaV3Provider(FAKE_SITE_KEY)
+      });
+      const token = await getDebugToken();
+      expect(token).to.equal('abcdefg');
+      expect(logStub).to.be.calledWith(match('abcdefg'));
+      self.FIREBASE_APPCHECK_DEBUG_TOKEN = undefined;
+    });
 
     it('initialize reCAPTCHA when a ReCaptchaV3Provider is provided', () => {
       const initReCAPTCHAStub = stub(reCAPTCHA, 'initialize').returns(

packages/app-check/src/api.ts

@@ -35,6 +35,8 @@ import {
   isValid
 } from './internal-api';
 import { readTokenFromStorage } from './storage';
+import { getDebugToken, initializeDebugMode, isDebugMode } from './debug';
+import { logger } from './logger';
 
 declare module '@firebase/component' {
   interface NameServiceMapping {
@@ -65,6 +67,21 @@ export function initializeAppCheck(
         options.isTokenAutoRefreshEnabled &&
       initialOptions.provider.isEqual(options.provider)
     ) {
+      // Log a warning if `initializeAppCheck()` is called after the first time
+      // if this app is still in debug mode, and show the token.
+      // If it's the first time, `initializeDebugMode()` already logs a message.
+      if (isDebugMode()) {
+        logger.warn(
+          `App Check is in debug mode. To turn off debug mode, unset ` +
+            `the global variable FIREBASE_APPCHECK_DEBUG_TOKEN and ` +
+            `restart the app.`
+        );
+        // Make this a separate console statement so user will at least have the
+        // first message if the token promise doesn't resolve in time.
+        void getDebugToken().then(token =>
+          logger.warn(`Debug token is ${token}.`)
+        );
+      }
       return existingInstance;
     } else {
       throw ERROR_FACTORY.create(AppCheckError.ALREADY_INITIALIZED, {
@@ -73,6 +90,9 @@ export function initializeAppCheck(
     }
   }
 
+  // Only read global variable on first call to `initializeAppCheck()`.
+  initializeDebugMode();
+
   const appCheck = provider.initialize({ options });
   _activate(app, options.provider, options.isTokenAutoRefreshEnabled);
 

packages/app-check/src/index.ts

@@ -28,7 +28,6 @@ import {
 } from '@firebase/component';
 import { _AppCheckComponentName } from './public-types';
 import { factory, internalFactory } from './factory';
-import { initializeDebugMode } from './debug';
 import { _AppCheckInternalComponentName } from './types';
 import { name, version } from '../package.json';
 
@@ -82,4 +81,3 @@ function registerAppCheck(): void {
 }
 
 registerAppCheck();
-initializeDebugMode();