Angular 提供程序，循环依赖错误

Question

我收到此错误：
提供者解析错误：无法实例化循环依赖！

我有一个组件可以对我的后端进行 http 调用：
backend.component.ts

import { HttpClient } from '@angular/common/http';
public basicQuery(): void {
  this.httpClient.get('http://...')
    .subscribe(
    (response) => {

    },
    error => {

    });
}

我每次调用都使用拦截器。
token.interceptor.ts

public intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
  request = request.clone({
    setHeaders: {
      token: this.auth.getToken()
    }
  });

  return next
    .handle(request)
    .do(
    (response: HttpEvent<any>) => {
    },
    (error: any) => {
      return false;
  });
}

如果我收到错误，我会在我的自定义错误处理程序中进行处理，因为我想将错误发送到我的后端。
custom-error-handler.ts

handleError(error): void {
  this.errorLogService.logServer(error);
  super.handleError(error);
}

因此我使用服务。
errorLog.service.ts

import { HttpClient } from '@angular/common/http';
logServer(error: Error) {
  this.httpClient.post('http://...', JSON.stringify(error.message))
    .subscribe(
    (response) => { },
    (error) => { });
}

这就是问题所在，因为我也使用 httpClient。 但是我怎样才能避免这种失败，如何做对呢？ 现在我使用 'Http' 而不是 'HttpClient'。

更新 1

private auth: AuthService;

constructor(
  private utils: Utils,
  private router: Router,
  private injector: Injector
) {
  this.auth = this.injector.get(AuthService);
}

public intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
  request = request.clone({
    setHeaders: {
      token: this.auth.getToken()
    }
  });

  return next
    .handle(request)
    .do(
      (response: HttpEvent<any>) => { },
      (error: any) => { return false }
    );
}

更新 2

将 AuthService 和 Router 注入 body 可以解决问题：

public intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
  const started = Date.now();

  this.auth = this.injector.get(AuthService);
  this.router = this.injector.get(Router);

  (...)
}

Answer 1

你可以这样做，不要在构造函数中注入服务，而是在你的函数体中这样做。在这里您也不会遇到诸如达到最大呼叫数之类的问题。

@Injectable()
export class YourInterceptor implements HttpInterceptor {
  yourService: YourService;
  constructor(private inject: Injector) {
    //this.yourService = inject.get(YourService);
  }

  intercept(
    request: HttpRequest<any>,
    next: HttpHandler
  ): Observable<HttpEvent<any>> {

    this.yourService = this.inject.get(YourService);

    request = request.clone({
       setHeaders: {
          token: this.YourService.getToken()
       }
    });

    return next.handle(request);    
  }
}

根据你的构造函数试试这个，

private auth: AuthService;
private router: Router;

constructor(
  private utils: Utils,
  private injector: Injector
) {

}

public intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
  this.router = this.injector.get(Router);
  this.auth = this.injector.get(AuthService);
  request = request.clone({
    setHeaders: {
      token: this.auth.getToken()
    }
  });

  return next
    .handle(request)
    .do(
      (response: HttpEvent<any>) => { },
      (error: any) => { return false }
    );
}