✨ add ability for viewer to notify subscriptions that the state has c…

…hanged (#21720)

* Add a reset message to the viewer interface

* lint

* add tests + fixes

* fix merge

extensions/amp-subscriptions/0.1/test/test-viewer-platform.js

@@ -19,6 +19,7 @@ import {Dialog} from '../dialog';
 import {Entitlement, GrantReason} from '../entitlement';
 import {PageConfig} from '../../../../third_party/subscriptions-project/config';
 import {ServiceAdapter} from '../service-adapter';
+import {Services} from '../../../../src/services';
 import {SubscriptionAnalytics} from '../analytics';
 import {ViewerSubscriptionPlatform} from '../viewer-subscription-platform';
 import {getWinOrigin} from '../../../../src/url';
@@ -27,6 +28,7 @@ describes.fakeWin('ViewerSubscriptionPlatform', {amp: true}, env => {
   let ampdoc, win;
   let viewerPlatform;
   let serviceAdapter, sendAuthTokenStub;
+  let resetPlatformsStub, messageCallback;
   const currentProductId = 'example.org:basic';
   const origin = 'origin';
   const entitlementData = {source: 'local', raw: 'raw',
@@ -60,6 +62,9 @@ describes.fakeWin('ViewerSubscriptionPlatform', {amp: true}, env => {
         .callsFake(() => new Dialog(ampdoc));
     sandbox.stub(serviceAdapter, 'getReaderId')
         .callsFake(() => Promise.resolve('reader1'));
+    resetPlatformsStub = sandbox.stub(serviceAdapter, 'resetPlatforms');
+    sandbox.stub(Services.viewerForDoc(ampdoc),'onMessage')
+        .callsFake((message, cb) => { messageCallback = cb; });
     viewerPlatform = new ViewerSubscriptionPlatform(
         ampdoc, serviceConfig, serviceAdapter, origin);
     sandbox.stub(viewerPlatform.viewer_,
@@ -89,6 +94,13 @@ describes.fakeWin('ViewerSubscriptionPlatform', {amp: true}, env => {
     });
   });
 
+  describe('subscriptionchange message', () => {
+    it('should call resetPlatforms() on a subscriptionchange message', () => {
+      (messageCallback)();
+      expect(resetPlatformsStub).to.be.called;
+    });
+  });
+
   it('Should  allow prerender', () => {
     expect(viewerPlatform.isPrerenderSafe()).to.be.true;
   });

extensions/amp-subscriptions/0.1/viewer-subscription-platform.js

@@ -41,6 +41,9 @@ export class ViewerSubscriptionPlatform {
     /** @private @const */
     this.ampdoc_ = ampdoc;
 
+    /** @private @const */
+    this.serviceAdapter_ = serviceAdapter;
+
     /** @private @const {!PageConfig} */
     this.pageConfig_ = serviceAdapter.getPageConfig();
 
@@ -50,6 +53,8 @@ export class ViewerSubscriptionPlatform {
 
     /** @const @private {!../../../src/service/viewer-impl.Viewer} */
     this.viewer_ = Services.viewerForDoc(this.ampdoc_);
+    this.viewer_.onMessage('subscriptionchange',
+        this.subscriptionChange_.bind(this));
 
     /** @private @const {!JwtHelper} */
     this.jwtHelper_ = new JwtHelper(ampdoc.win);
@@ -212,6 +217,15 @@ export class ViewerSubscriptionPlatform {
   decorateUI(element, action, options) {
     return this.platform_.decorateUI(element, action, options);
   }
+
+  /**
+   * Handles a reset message from the viewer which indicates
+   * subscription state changed.  Eventually that will trigger
+   * a new getEntitlements() message exchange.
+   */
+  subscriptionChange_() {
+    this.serviceAdapter_.resetPlatforms();
+  }
 }
 
 /**