angular - 有什么方法可以改变 Angular 5 HttpInterceptor 中的响应吗？

Question

对于我的应用程序，我创建了以下 HttpInterceptor。有没有办法从这里向请求订阅者返回响应的更改版本？

import { Injectable } from '@angular/core';
import { HttpRequest, HttpResponse, HttpErrorResponse, HttpHandler, HttpEvent, HttpInterceptor } from '@angular/common/http';
import { Observable } from 'rxjs/Observable';
import { Router } from '@angular/router';

@Injectable()
export class RequestInterceptor implements HttpInterceptor {
    constructor(
        private router: Router
    ) { }

    intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        return next.handle(request).do((event: HttpEvent<any>) => {
            if (event instanceof HttpResponse) {
                // any way to alter response that gets sent to the request subscriber?
            }
        }, (error: any) => {    
            if (error instanceof HttpErrorResponse) {
                if (error.status === 401 || error.status === 403) {
                    console.log('The authentication session has expired or the user is not authorised. Redirecting to login page.');
                    this.router.navigate(['/login']);
                }
            }
        });
    }
}

谢谢。

Answer 1

就像 Marcel Lamothe 在他的回答中指出的那样，您可以通过克隆事件和更改 body 属性来更改响应。

import { Injectable } from '@angular/core';
import { HttpRequest, HttpResponse, HttpErrorResponse, HttpHandler, HttpEvent, HttpInterceptor } from '@angular/common/http';
import { Observable } from 'rxjs/Observable';
import { Router } from '@angular/router';

@Injectable()
export class RequestInterceptor implements HttpInterceptor {
    constructor(
        private router: Router
    ) {}

    intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        return next.handle(request).map((event: HttpEvent<any>) => {
            if (event instanceof HttpResponse) {
                // change the response body here
                return event.clone({
                    body: 'myCustomResponse'
                });
            }

            return event;
        }).do((event: HttpEvent<any>) => {}, (error: any) => {
            if (error instanceof HttpErrorResponse) {
                if (error.status === 401 || error.status === 403) {
                    console.log('The authentication session has expired or the user is not authorised. Redirecting to login page.');
                    this.router.navigate(['/login']);
                }
            }
        });
    }
}