如何向Angular 4应用程序添加多个独立的HTTP拦截器？
我尝试通过使用多个拦截器扩展providers数组来添加它们。但实际上只执行了最后一个，Interceptor1被忽略了。
@NgModule({
declarations: [ /* ... */ ],imports: [ /* ... */ HttpModule ],providers: [
{
provide: Http,useFactory: (xhrBackend: XHRBackend,requestOptions: RequestOptions) =>
new Interceptor1(xhrBackend,requestOptions),deps: [XHRBackend,RequestOptions],},{
provide: Http,requestOptions: RequestOptions) =>
new Interceptor2(xhrBackend,RequestOptions]
},],bootstrap: [AppComponent]
})
export class AppModule {}
我显然可以将它们组合成一个Interceptor类，这应该可行。但是，我想避免这种情况，因为这些拦截器具有完全不同的目的(一个用于错误处理，一个用于显示加载指示符)。
Http不允许有多个自定义实现。但正如@estus提到的那样，Angular团队最近添加了一个新的
HttpClient服务(版本4.3)，它支持多个拦截器概念。您不需要像使用旧的Http那样扩展HttpClient。您可以为HTTP_INTERCEPTORS提供一个实现，它可以是一个带有’multi：true’选项的数组：
import {HTTP_INTERCEPTORS,HttpClientModule} from '@angular/common/http';
...
@NgModule({
...
imports: [
...,HttpClientModule
],providers: [
...,{
provide: HTTP_INTERCEPTORS,useClass: InterceptorOne,multi: true,useClass: InterceptorTwo,}
],...
})
拦截器：
import {HttpEvent,HttpHandler,HttpInterceptor,HttpRequest} from '@angular/common/http';
...
@Injectable()
export class InterceptorOne implements HttpInterceptor {
intercept(req: HttpRequest<any>,next: HttpHandler): Observable<HttpEvent<any>> {
console.log('InterceptorOne is working');
return next.handle(req);
}
}
@Injectable()
export class InterceptorTwo implements HttpInterceptor {
intercept(req: HttpRequest<any>,next: HttpHandler): Observable<HttpEvent<any>> {
console.log('InterceptorTwo is working');
return next.handle(req);
}
}
import {HttpClient} from '@angular/common/http';
...
@Component({ ... })
export class SomeComponent implements OnInit {
constructor(private http: HttpClient) {}
ngOnInit(): void {
this.http.get('http://some_url').subscribe();
}
}
