Angular HttpInterceptor不更改标题 [英] Angular HttpInterceptor not changing header

问题描述

我编写了一个有角度的(4.3.6)HttpInterceptor，以添加一些标头字段，但是如果在调试器中检查标头字段，则标头不会更新.有什么主意吗?

I wrote an angular (4.3.6) HttpInterceptor to add some header fields, but the header doesn't get updated if I inspect them in the debugger. Any idea?

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

@Injectable()
export class AuthInterceptor implements HttpInterceptor {


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

        console.log('AuthInterceptor at work');

        const contentTypeReq = req.clone({
            headers: req.headers.set('Content-Type', 'application/json')
        });

        const token  = localStorage.getItem('token');
        if (token) {
            const authReq = contentTypeReq.clone({
                headers: req.headers.set('Authorization', 'Bearer ' + token)
            });
            return next.handle(authReq);
        }

        // Pass on the cloned request instead of the original request.
        return next.handle(contentTypeReq);
    }
}

推荐答案

它们很懒.例如 keys方法看起来像:

They are lazy. For example keys method looks like:

keys(): string[] {
    this.init(); <== initialize

    return Array.from(this.normalizedNames.values());
}

如果要检查它们，只需致电:

If you want to check them just call:

req.headers.keys()

如果要检查值，可以使用get或getAll方法:

If you want to check value you can use get or getAll method:

req.headers.getAll('Content-Type')

或者您可以从控制台调用init方法，然后您将能够在headers地图中查看标题

Or you can call init method from console and then you will be able to see headers in headers Map

此外，当角度将标头添加到请求，它使用

Moreover when angular adds headers to request it uses forEach method that calls init method too.

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