JCU: SSR idle timer only in the browser, drain xhr2 redirect bodies

src/app/core/auth/auth.effects.spec.ts

@@ -22,6 +22,7 @@ import {
   throwError as observableThrow,
 } from 'rxjs';
 
+import { environment } from '../../../environments/environment';
 import {
   AppState,
   storeModuleConfig,
@@ -52,6 +53,7 @@ import {
   RetrieveAuthMethodsErrorAction,
   RetrieveAuthMethodsSuccessAction,
   RetrieveTokenAction,
+  SetUserAsIdleAction,
 } from './auth.actions';
 import { AuthEffects } from './auth.effects';
 import { authReducer } from './auth.reducer';
@@ -107,6 +109,28 @@ describe('AuthEffects', () => {
     store = TestBed.inject(Store as any);
   });
 
+  describe('trackIdleness$', () => {
+    let emitted: any[];
+
+    beforeEach(() => {
+      emitted = [];
+      actions = of({ type: StoreActionTypes.REHYDRATE });
+    });
+
+    it('should set the user as idle when the timer runs out in the browser', fakeAsync(() => {
+      authEffects.trackIdleness$.subscribe((action) => emitted.push(action));
+      tick(environment.auth.ui.timeUntilIdle);
+      expect(emitted).toEqual([new SetUserAsIdleAction()]);
+    }));
+
+    it('should not start the timer on the server', fakeAsync(() => {
+      (authEffects as any).platformId = 'server';
+      authEffects.trackIdleness$.subscribe((action) => emitted.push(action));
+      tick(environment.auth.ui.timeUntilIdle);
+      expect(emitted).toEqual([]);
+    }));
+  });
+
   describe('authenticate$', () => {
     describe('when credentials are correct', () => {
       it('should return a AUTHENTICATE_SUCCESS action in response to a AUTHENTICATE action', () => {

src/app/core/auth/auth.effects.ts

@@ -1,6 +1,9 @@
+import { isPlatformBrowser } from '@angular/common';
 import {
+  Inject,
   Injectable,
   NgZone,
+  PLATFORM_ID,
   Type,
 } from '@angular/core';
 // import @ngrx
@@ -304,6 +307,8 @@ export class AuthEffects {
    * @method trackIdleness
    */
   public trackIdleness$: Observable<Action> = createEffect(() => this.actions$.pipe(
+    // Only in the browser: on the server this timer keeps an unfinished render in memory until it fires
+    filter(() => isPlatformBrowser(this.platformId)),
     filter((action: Action) => !IDLE_TIMER_IGNORE_TYPES.includes(action.type)),
     // Using switchMap the effect will stop subscribing to the previous timer if a new action comes
     // in, and start a new timer
@@ -323,11 +328,13 @@ export class AuthEffects {
    * @param {AuthorizationDataService} authorizationsService
    * @param {AuthService} authService
    * @param {Store} store
+   * @param {object} platformId
    */
   constructor(private actions$: Actions,
               private zone: NgZone,
               private authorizationsService: AuthorizationDataService,
               private authService: AuthService,
-              private store: Store<AppState>) {
+              private store: Store<AppState>,
+              @Inject(PLATFORM_ID) private platformId: object) {
   }
 }

src/app/core/services/server-xhr.service.ts

@@ -33,6 +33,9 @@ const agentOptions: HttpAgentOptions = {
 const httpAgent = new HttpAgent(agentOptions);
 const httpsAgent = new HttpsAgent(agentOptions);
 
+// The status codes xhr2 follows on its own.
+const REDIRECT_STATUSES = [301, 302, 303, 307, 308];
+
 /**
  * Constructs the XMLHttpRequest instances used for all HttpClient requests.
  * Emulated by https://github.com/pwnall/node-xhr2 on the server.
@@ -43,6 +46,8 @@ const httpsAgent = new HttpsAgent(agentOptions);
  *   This was added to be able to perform a working XSRF request from the node server, as it needs to set a cookie for the XSRF token.
  * - Override NodeJS HTTP(S) agents to keep sessions alive between requests.
  *   This improves SSR performance by reducing REST request overhead on the server.
+ * - Read and discard the body of redirect responses that xhr2 follows. Otherwise their socket stays busy
+ *   until the REST server closes it, and keeps the SSR app that made the request in memory.
  *
  * Note that this must be provided in ServerAppModule;
  * it doesn't work when added as a Universal engine provider.
@@ -60,6 +65,14 @@ export class ServerXhrService implements XhrFactory {
       httpsAgent,
     });
 
+    const onHttpResponse = (xhr as any)._onHttpResponse;
+    (xhr as any)._onHttpResponse = function(request, response) {
+      if (REDIRECT_STATUSES.includes(response.statusCode)) {
+        response.resume();
+      }
+      return onHttpResponse.call(this, request, response);
+    };
+
     return xhr;
   }
 }