Adding ServerTransferStateModule for AU with custom http interceptor for cache transfer.

frontend/src/app/services/http-cache.interceptor.ts

@@ -0,0 +1,42 @@
+import { Inject, Injectable, PLATFORM_ID } from '@angular/core';
+import { HttpInterceptor, HttpEvent, HttpRequest, HttpHandler, HttpResponse } from '@angular/common/http';
+import { Observable, of } from 'rxjs';
+import { tap } from 'rxjs/operators';
+import { TransferState, makeStateKey } from '@angular/platform-browser';
+import { isPlatformBrowser } from '@angular/common';
+
+@Injectable()
+export class HttpCacheInterceptor implements HttpInterceptor {
+  isBrowser: boolean = isPlatformBrowser(this.platformId);
+
+  constructor(
+    private transferState: TransferState,
+    @Inject(PLATFORM_ID) private platformId: any,
+  ) { }
+
+  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
+    if (this.isBrowser && request.method === 'GET') {
+
+      const cachedResponse = this.transferState.get(makeStateKey(request.url), null);
+      if (cachedResponse) {
+        const modifiedResponse = new HttpResponse<any>({
+          headers: cachedResponse.headers,
+          body: cachedResponse.body,
+          status: cachedResponse.status,
+          statusText: cachedResponse.statusText,
+          url: cachedResponse.url
+        });
+        this.transferState.remove(makeStateKey(request.url));
+        return of(modifiedResponse);
+      }
+    }
+
+    return next.handle(request)
+      .pipe(tap((event: HttpEvent<any>) => {
+        if (!this.isBrowser && event instanceof HttpResponse) {
+          const keyId = request.url.split('/').slice(3).join('/');
+          this.transferState.set(makeStateKey('/' + keyId), event);
+        }
+      }));
+  }
+}