fix(platform-server): avoid dependency cycle when using http interceptor (#24229)

Fixes #23023.

When a HTTP Interceptor injects HttpClient it causes a DI cycle. This fix is to use Injector to lazily inject HTTP_INTERCEPTORS while setting up the HttpHandler on the server so as to break the cycle.

PR Close #24229

packages/common/http/public_api.ts

@@ -11,7 +11,7 @@ export {HttpClient} from './src/client';
 export {HttpHeaders} from './src/headers';
 export {HTTP_INTERCEPTORS, HttpInterceptor} from './src/interceptor';
 export {JsonpClientBackend, JsonpInterceptor} from './src/jsonp';
-export {HttpClientJsonpModule, HttpClientModule, HttpClientXsrfModule, interceptingHandler as ɵinterceptingHandler} from './src/module';
+export {HttpClientJsonpModule, HttpClientModule, HttpClientXsrfModule, HttpInterceptingHandler as ɵHttpInterceptingHandler} from './src/module';
 export {HttpParameterCodec, HttpParams, HttpUrlEncodingCodec} from './src/params';
 export {HttpRequest} from './src/request';
 export {HttpDownloadProgressEvent, HttpErrorResponse, HttpEvent, HttpEventType, HttpHeaderResponse, HttpProgressEvent, HttpResponse, HttpResponseBase, HttpSentEvent, HttpUserEvent} from './src/response';

packages/common/http/src/module.ts

@@ -42,23 +42,6 @@ export class HttpInterceptingHandler implements HttpHandler {
   }
 }
 
-/**
- * Constructs an `HttpHandler` that applies a bunch of `HttpInterceptor`s
- * to a request before passing it to the given `HttpBackend`.
- *
- * Meant to be used as a factory function within `HttpClientModule`.
- *
- *
- */
-export function interceptingHandler(
-    backend: HttpBackend, interceptors: HttpInterceptor[] | null = []): HttpHandler {
-  if (!interceptors) {
-    return backend;
-  }
-  return interceptors.reduceRight(
-      (next, interceptor) => new HttpInterceptorHandler(next, interceptor), backend);
-}
-
 /**
  * Factory function that determines where to store JSONP callbacks.
  *

packages/platform-server/src/http.ts

@@ -8,10 +8,10 @@
 
 const xhr2: any = require('xhr2');
 
-import {Injectable, Optional, Provider} from '@angular/core';
+import {Injectable, Injector, Optional, Provider, InjectFlags} from '@angular/core';
 import {BrowserXhr, Connection, ConnectionBackend, Http, ReadyState, Request, RequestOptions, Response, XHRBackend, XSRFStrategy} from '@angular/http';
 
-import {HttpEvent, HttpRequest, HttpHandler, HttpInterceptor, HTTP_INTERCEPTORS, HttpBackend, XhrFactory, ɵinterceptingHandler as interceptingHandler} from '@angular/common/http';
+import {HttpEvent, HttpRequest, HttpHandler, HttpInterceptor, HTTP_INTERCEPTORS, HttpBackend, XhrFactory, ɵHttpInterceptingHandler as HttpInterceptingHandler} from '@angular/common/http';
 
 import {Observable, Observer, Subscription} from 'rxjs';
 
@@ -156,9 +156,8 @@ export function httpFactory(xhrBackend: XHRBackend, options: RequestOptions) {
   return new Http(macroBackend, options);
 }
 
-export function zoneWrappedInterceptingHandler(
-    backend: HttpBackend, interceptors: HttpInterceptor[] | null) {
-  const realBackend: HttpBackend = interceptingHandler(backend, interceptors);
+export function zoneWrappedInterceptingHandler(backend: HttpBackend, injector: Injector) {
+  const realBackend: HttpBackend = new HttpInterceptingHandler(backend, injector);
   return new ZoneClientBackend(realBackend);
 }
 
@@ -168,6 +167,6 @@ export const SERVER_HTTP_PROVIDERS: Provider[] = [
   {provide: XhrFactory, useClass: ServerXhr}, {
     provide: HttpHandler,
     useFactory: zoneWrappedInterceptingHandler,
-    deps: [HttpBackend, [new Optional(), HTTP_INTERCEPTORS]]
+    deps: [HttpBackend, Injector]
   }
 ];

packages/platform-server/test/integration_spec.ts

@@ -8,15 +8,16 @@
 
 import {AnimationBuilder, animate, style, transition, trigger} from '@angular/animations';
 import {APP_BASE_HREF, PlatformLocation, isPlatformServer} from '@angular/common';
-import {HttpClient, HttpClientModule} from '@angular/common/http';
+import {HTTP_INTERCEPTORS, HttpClient, HttpClientModule, HttpEvent, HttpHandler, HttpInterceptor, HttpRequest} from '@angular/common/http';
 import {HttpClientTestingModule, HttpTestingController} from '@angular/common/http/testing';
-import {ApplicationRef, CompilerFactory, Component, HostListener, Inject, Input, NgModule, NgModuleRef, NgZone, PLATFORM_ID, PlatformRef, ViewEncapsulation, destroyPlatform, getPlatform} from '@angular/core';
+import {ApplicationRef, CompilerFactory, Component, HostListener, Inject, Injectable, Input, NgModule, NgModuleRef, NgZone, PLATFORM_ID, PlatformRef, ViewEncapsulation, destroyPlatform, getPlatform} from '@angular/core';
 import {TestBed, async, inject} from '@angular/core/testing';
 import {Http, HttpModule, Response, ResponseOptions, XHRBackend} from '@angular/http';
 import {MockBackend, MockConnection} from '@angular/http/testing';
 import {BrowserModule, DOCUMENT, StateKey, Title, TransferState, makeStateKey} from '@angular/platform-browser';
 import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
 import {BEFORE_APP_SERIALIZED, INITIAL_CONFIG, PlatformState, ServerModule, ServerTransferStateModule, platformDynamicServer, renderModule, renderModuleFactory} from '@angular/platform-server';
+import {Observable} from 'rxjs';
 import {first} from 'rxjs/operators';
 
 @Component({selector: 'app', template: `Works!`})
@@ -202,6 +203,26 @@ export class HttpAfterExampleModule {
 export class HttpClientExampleModule {
 }
 
+@Injectable()
+export class MyHttpInterceptor implements HttpInterceptor {
+  constructor(private http: HttpClient) {}
+
+  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
+    return next.handle(req);
+  }
+}
+
+@NgModule({
+  bootstrap: [MyServerApp],
+  declarations: [MyServerApp],
+  imports: [ServerModule, HttpClientModule, HttpClientTestingModule],
+  providers: [
+    {provide: HTTP_INTERCEPTORS, multi: true, useClass: MyHttpInterceptor},
+  ],
+})
+export class HttpInterceptorExampleModule {
+}
+
 @Component({selector: 'app', template: `<img [src]="'link'">`})
 class ImageApp {
 }
@@ -750,6 +771,21 @@ class EscapedTransferStoreModule {
              });
            });
          }));
+      it('can use HttpInterceptor that injects HttpClient', () => {
+        const platform =
+            platformDynamicServer([{provide: INITIAL_CONFIG, useValue: {document: '<app></app>'}}]);
+        platform.bootstrapModule(HttpInterceptorExampleModule).then(ref => {
+          const mock = ref.injector.get(HttpTestingController) as HttpTestingController;
+          const http = ref.injector.get(HttpClient);
+          ref.injector.get<NgZone>(NgZone).run(() => {
+            http.get('http://localhost/testing').subscribe(body => {
+              NgZone.assertInAngularZone();
+              expect(body).toEqual('success!');
+            });
+            mock.expectOne('http://localhost/testing').flush('success!');
+          });
+        });
+      });
     });
 
     describe('ServerTransferStoreModule', () => {