当我在HttpInterceptor类中注入使用HttpClient的服务时，Angular 6进入循环依赖的无限循环

Question

我已经在不同的Angular版本中多次发现此问题，但是有多个消息来源说它已经得到解决，例如，关于Stackoverflow的另一个类似问题是有这个答案，它说它已在Angular 5.2中解决，在Github上还有其他问题在说在6.0.2中解决，我正在使用Angular 6.0.3，但是每当我尝试在HttpInterceptor类中注入使用HttpClient的服务时（仍然会收到一个问题）（如果在该请求中接收到jwt，则应该在请求中添加jwt令牌）服务）

我没有收到具有周期性依赖关系的警告或错误，请在浏览器控制台中看到数千个Interceptor正在调用服务的请求，反之亦然。

解决此问题的正确方法是什么？（最好不将jwt存储在本地存储中）

（即使用拦截器并从服务中获取jwt）

我的服务：

 ....
 // only showing parts that matter, HttpClient is injected here
 // to be used in calling the API services

  constructor(public http: HttpClient, private route: ActivatedRoute,
 public translate: TranslateService, private router: Router,
 public snackBar: MatSnackBar, private notification: NotificationService) {

//

我的HttpInterceptor：

import { Observable } from 'rxjs';
import { Location } from '@angular/common';
import { Injectable, Injector } from '@angular/core';
import { HttpInterceptor } from '@angular/common/http';
import { HttpRequest } from '@angular/common/http';
import { HttpHandler } from '@angular/common/http';
import { HttpEvent } from '@angular/common/http';
import { HttpHeaders } from '@angular/common/http';
import { DataService } from './data/data.service';

@Injectable()
export class CustomHttpInterceptor implements HttpInterceptor {
  constructor(private injector: Injector) {}

intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
  const dataService = this.injector.get(DataService);

  console.log('hey there, we are here INTERCEPTOR');
  if (dataService.jwt) {
        request = request.clone({
          setHeaders: {
            Authorization: `Bearer ${dataService.jwt}`
          }
        });
      }

    return next.handle(request);
  }
}

ng版本

Angular CLI: 6.0.8
Node: 10.0.0
OS: win32 x64
Angular: 6.0.7
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.6.3
@angular-devkit/build-angular     0.6.3
@angular-devkit/build-optimizer   0.6.3
@angular-devkit/core              0.6.3
@angular-devkit/schematics        0.6.8
@angular/cdk                      6.1.0
@angular/cli                      6.0.8
@angular/flex-layout              6.0.0-beta.15
@angular/material                 6.3.1
@ngtools/webpack                  6.0.3
@schematics/angular               0.6.8
@schematics/update                0.6.8
rxjs                              6.2.1
typescript                        2.7.2
webpack                           4.8.3

Answer 1

我可以通过在服务中自己实例化 HttpClient 来解决这个问题：

@Injectable()
export class DataService {

  private http: HttpClient;

  constructor(httpBackend: HttpBackend) {
    this.http = new HttpClient(httpBackend);    
  }
}

这打破了我的案例中的无限循环问题（使用 Angular@6.1.10）。