start of caching, csrf interceptor, and device service

src/app/http-interceptors/csrf-intercepor.ts

@@ -0,0 +1,29 @@
+import { Injectable } from '@angular/core';
+import { deviceID } from '../api-utils';
+import {
+    HttpInterceptor, HttpHandler, HttpRequest, HttpHeaders
+} from '@angular/common/http';
+
+import { CookieService } from '../cookie.service';
+
+
+@Injectable()
+export class CSRFInterceptor implements HttpInterceptor {
+
+    constructor(private cookieService: CookieService) { }
+
+    intercept(req: HttpRequest<any>, next: HttpHandler) {
+        const dID: String = deviceID();
+        const csrfCookie = 'CSRF-Token-' + dID
+
+        // Clone the request and replace the original headers with
+        // cloned headers, updated with the CSRF information.
+        const csrfReq = req.clone({
+            headers: req.headers.set('X-CSRF-Token-' + dID,
+                this.cookieService.getCookie(csrfCookie))
+        });
+
+        // send cloned request with header to the next handler.
+        return next.handle(csrfReq);
+    }
+}

src/app/http-interceptors/index.ts

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+/* "Barrel" of Http Interceptors */
+import { HTTP_INTERCEPTORS } from '@angular/common/http';
+import { CSRFInterceptor } from './csrf-intercepor';
+
+/** Http interceptor providers in outside-in order */
+export const httpInterceptorProviders = [
+    { provide: HTTP_INTERCEPTORS, useClass: CSRFInterceptor, multi: true },
+];