Question

我可以在HttpInterceptor内使用承诺吗？例如：

export class AuthInterceptor implements HttpInterceptor{
this.someService.someFunction()
    .then((data)=>{
       //do something with data and then
       return next.handle(req);
    });
}

为什么我需要这个？因为我需要在向服务器发出请求之前获取一个令牌以添加到请求标头。

我的拦截器：

@Injectable()
export class AuthInterceptor implements HttpInterceptor{

    constructor(private authService: AuthService){}

    intercept(req: HttpRequest<any>, next: HttpHandler) : Observable<HttpEvent<any>>{
        console.log('Intercepted!');
        // return next.handle(req);
        this.authService.getToken()
            .then((token)=>{
                console.log(token);
                const reqClone = req.clone({
                    headers: req.headers
                            .set('Authorization', 'Bearer ' + token)
                            .append('Content-Type', application/json')
                });
                console.log(reqClone);
                return next.handle(reqClone);
            })
            .catch((err)=>{
                console.log('error in interceptor' + err);
                return null;
            });
    }
}

请求：

this.http.post(this.baseURL + 'hero', data)
                    .subscribe(
                            (res: any) => {
                                console.log('Saved Successfully.');
                                console.log(res);
                            },
                            (err: any) => {
                                console.log('Save Error.' + err);
                            }
                        );

我面临的问题：

- ＆gt;我在解决承诺之前收到此错误。

You provided 'undefined' where a stream was expected. You can provide an Observable, Promise, Array, or Iterable.

承诺resloves，我得到了我的令牌但错误之后。

Answer 1

更新：使用rxjs@6.x

import { from, Observable } from 'rxjs';
import { switchMap } from 'rxjs/operators';

@Injectable()
export class AuthInterceptor implements HttpInterceptor {

    constructor(private authService: AuthService){}

    intercept(request: HttpRequest<any>, next: HttpHandler) : Observable<HttpEvent<any>>{
        return from(this.authService.getToken())
              .pipe(
                switchMap(token => {
                   const headers = request.headers
                            .set('Authorization', 'Bearer ' + token)
                            .append('Content-Type', application/json');
                   const requestClone = request.clone({
                     headers 
                    });
                  return next.handle(requestClone);
                })
               );
    }
}

原始回答

是的，您可以将所需的服务注入到拦截器的构造函数方法中，并在intercept的实现中检索该值，创建一个新的更新的http请求并处理它。

我对承诺不满意，所以你可以尝试以下方法：

import { fromPromise } from 'rxjs/observable/fromPromise';

@Injectable()
export class AuthInterceptor implements HttpInterceptor{

    constructor(private authService: AuthService){}

    intercept(req: HttpRequest<any>, next: HttpHandler) : Observable<HttpEvent<any>>{
        return fromPromise(this.authService.getToken())
              .switchMap(token => {
                   const headers = req.headers
                            .set('Authorization', 'Bearer ' + token)
                            .append('Content-Type', application/json');
                   const reqClone = req.clone({
                     headers 
                    });
                  return next.handle(reqClone);
             });
    }
}

Answer 2

对于RxJS 6+我已经更新了Jota.Toledo的答案：

import { fromPromise } from 'rxjs/observable/fromPromise';

@Injectable()
export class AuthInterceptor implements HttpInterceptor{
constructor(private authService: AuthService){}
intercept(req: HttpRequest<any>, next: HttpHandler) : Observable<HttpEvent<any>>{
    return fromPromise(this.authService.getToken())
          .pipe(switchMap(token => {
               const headers = req.headers
                        .set('Authorization', 'Bearer ' + token)
                        .append('Content-Type', application/json');
               const reqClone = req.clone({
                 headers 
                });
              return next.handle(reqClone);
         }));
 }  
}

Answer 3

轮到我了（感谢Jota.Toledo和Capripio）：

1）将“ fromPromise”切换为“ from”-> fromPromise does not exist on type Observable

2）修复'application / json'报价

import { Observable, from } from 'rxjs';
import { switchMap } from 'rxjs/operators';

@Injectable()
export class AuthInterceptor implements HttpInterceptor {

  constructor(private authService: AuthService){}

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

      return from(this.authService.getToken()).pipe(
        switchMap(token => {
            const headers = req.headers
                .set('Authorization', 'Bearer ' + token)
                .append('Content-Type', 'application/json');
            const reqClone = req.clone({
                headers
            });
            return next.handle(reqClone);
        }));
   }
}

我的RxJs版本：“ 6.2.2” 希望能有所帮助！

在Angular HttpClient拦截器中使用promise

3 个答案: