这是一个实施示例。

Question

在angularjs中，我们有http拦截器

$httpProvider.interceptors.push('myHttpInterceptor');

我们可以挂钩到所有http调用，并显示或隐藏加载条，进行日志记录等。

angular2中的等价物是什么？

Answer 1

正如@Günter指出的那样，没有办法注册拦截器。您需要扩展Http类并将您的拦截处理放在HTTP调用

首先，您可以创建一个扩展Http：

的类

@Injectable()
export class CustomHttp extends Http {
  constructor(backend: ConnectionBackend, defaultOptions: RequestOptions) {
    super(backend, defaultOptions);
  }

  request(url: string | Request, options?: RequestOptionsArgs): Observable<Response> {
    console.log('request...');
    return super.request(url, options).catch(res => {
      // do something
    });        
  }

  get(url: string, options?: RequestOptionsArgs): Observable<Response> {
    console.log('get...');
    return super.get(url, options).catch(res => {
      // do something
    });
  }
}

并按如下所述进行注册：

bootstrap(AppComponent, [HTTP_PROVIDERS,
    new Provider(Http, {
      useFactory: (backend: XHRBackend, defaultOptions: RequestOptions) => new CustomHttp(backend, defaultOptions),
      deps: [XHRBackend, RequestOptions]
  })
]);

在调用目标方法之前，可以添加request和requestError种类。

对于response，您需要将一些异步处理插入现有的处理链中。这取决于您的需要，但您可以使用Observable的运算符（如flatMap）。

最后，对于responseError，您需要在目标呼叫上调用catch运算符。这样，当响应中发生错误时，您将收到通知。

此链接可以帮助您：

Answer 2

<强>更新

Angular 4.3.0中引入的新HttpClient模块支持拦截器https://github.com/angular/angular/compare/4.3.0-rc.0...4.3.0

壮举（常见）：新的HttpClient API HttpClient是一个演变的   现有的Angular HTTP API，它与它一起存在于一个单独的   包，@ angular / common / http。这种结构确保了现有的   代码库可以慢慢迁移到新的API。

新的API显着改善了人体工程学和功能   遗留API。部分新功能列表包括：


键入的同步响应正文访问，包括对JSON正文类型的支持

JSON是假定的默认值，不再需要显式解析

拦截器允许将中间件逻辑插入管道

不可变的请求/响应对象

请求上传和响应下载的进度事件

请求后验证＆amp;基于冲洗的测试框架

<强>原始

Angular2还没有（还有）拦截器。您可以扩展Http，XHRBackend，BaseRequestOptions或任何其他相关类（至少在TypeScript和Dart中（不了解普通JS）。

另见

Answer 3

此存储库中有一个Http @ angular / core-like服务的实现：https://github.com/voliva/angular2-interceptors

您只需在bootstrap上声明该服务的提供程序，添加您需要的任何拦截器，它将可用于所有组件。

import { provideInterceptorService } from 'ng2-interceptors';

@NgModule({
  declarations: [
    ...
  ],
  imports: [
    ...,
    HttpModule
  ],
  providers: [
    MyHttpInterceptor,
    provideInterceptorService([
      MyHttpInterceptor,
      /* Add other interceptors here, like "new ServerURLInterceptor()" or
         just "ServerURLInterceptor" if it has a provider */
    ])
  ],
  bootstrap: [AppComponent]
})

Answer 4

自Angular 4.3开始受到限制（HttpInterCeptors回归4.3）

您可以创建自己的自定义HTTP类并使用rxjs Subject Service重用自定义Http类并在自定义类中实现您的行为。

使用包含一些rxjs主题的“HttpSubjectService”实现自定义Http类。

import { Injectable } from '@angular/core';
import { Http, ConnectionBackend, Request, RequestOptions, RequestOptionsArgs, Response } from '@angular/http';
import { Observable } from 'rxjs/Observable';


import { HttpSubjectService } from './httpSubject.service';


@Injectable()
export class CustomHttp extends Http {
   constructor(backend: ConnectionBackend, defaultOptions: RequestOptions, private httpSubjectService: HttpSubjectService) {
       super(backend, defaultOptions);

       //Prevent Ajax Request Caching for Internet Explorer
       defaultOptions.headers.append("Cache-control", "no-cache");
       defaultOptions.headers.append("Cache-control", "no-store");
       defaultOptions.headers.append("Pragma", "no-cache");
       defaultOptions.headers.append("Expires", "0");
   }

   request(url: string | Request, options?: RequestOptionsArgs): Observable<Response> {
       //request Start;
       this.httpSubjectService.addSpinner();
       return super.request(url, options).map(res => {
           //Successful Response;
           this.httpSubjectService.addNotification(res.json());
           return res;
       })
           .catch((err) => {
               //Error Response.
               this.httpSubjectService.removeSpinner();
               this.httpSubjectService.removeOverlay();

               if (err.status === 400 || err.status === 422) {
                   this.httpSubjectService.addHttp403(err);
                   return Observable.throw(err);
               } else if (err.status === 500) {
                   this.httpSubjectService.addHttp500(err);
                   return Observable.throw(err);
               } else {
                   return Observable.empty();
               }
           })
           .finally(() => {
               //After the request;
               this.httpSubjectService.removeSpinner();
           });
   }
}

用于注册CustomHttp类的自定义模块 - 在这里，您可以使用自己的CustomHttp实现覆盖Angular的默认Http实现。

import { NgModule, ValueProvider } from '@angular/core';
import { HttpModule, Http, XHRBackend, RequestOptions } from '@angular/http';

//Custom Http
import { HttpSubjectService } from './httpSubject.service';
import { CustomHttp } from './customHttp';

@NgModule({
    imports: [ ],
    providers: [
        HttpSubjectService,
        {
           provide: Http, useFactory: (backend: XHRBackend, defaultOptions: RequestOptions, httpSubjectService: HttpSubjectService) => {
                return new CustomHttp(backend, defaultOptions, httpSubjectService);
            },
            deps: [XHRBackend, RequestOptions, HttpSubjectService]
        }
    ]
})
export class CustomHttpCoreModule {

    constructor() { }
}

现在我们需要HttpSubjectService实现，我们可以使用“next”语句调用我们的rxjs主题。

import { Injectable } from '@angular/core';
import { Subject } from 'rxjs/Subject';

@Injectable()
export class HttpSubjectService {
    //https://github.com/ReactiveX/rxjs/blob/master/doc/subject.md
    //In our app.component.ts class we will subscribe to this Subjects
    public notificationSubject = new Subject();
    public http403Subject = new Subject();
    public http500Subject = new Subject();
    public overlaySubject = new Subject();
    public spinnerSubject = new Subject();

    constructor() { }

    //some Example methods we call in our CustomHttp Class
    public addNotification(resultJson: any): void {
        this.notificationSubject.next(resultJson);
    }

    public addHttp403(result: any): void {
        this.http403Subject.next(result);
    }

    public addHttp500(result: any): void {
        this.http500Subject.next(result);
    }

    public removeOverlay(): void {
        this.overlaySubject.next(0);
    }

    public addSpinner(): void {
        this.spinnerSubject.next(1);
    }

    public removeSpinner(): void {
        this.spinnerSubject.next(-1);
    }
}

调用我们需要订阅主题的自定义实现。 “app.component.ts”。

import { Component } from '@angular/core';
import { HttpSubjectService } from "../HttpInterception/httpSubject.service";
import { Homeservice } from "../HttpServices/home.service";

@Component({
    selector: 'app',
    templateUrl: './app.component.html',
})
export class AppComponent {
    private locals: AppLocalsModel = new AppLocalsModel();

    constructor(private httpSubjectService : HttpSubjectService, private homeService : Homeservice) {}

    ngOnInit(): void {
        this.notifications();
        this.httpRedirects();
        this.spinner();
        this.overlay();
    }

    public loadServiceData(): void {
        this.homeService.getCurrentUsername()
            .subscribe(result => {
                this.locals.username = result;
            });
    }

    private overlay(): void {
        this.httpSubjectService.overlaySubject.subscribe({
            next: () => {
              console.log("Call Overlay Service");
            }
        });
    }

    private spinner(): void {
        this.httpSubjectService.spinnerSubject.subscribe({
            next: (value: number) => {
              console.log("Call Spinner Service");
            }
        });
    }

    private notifications(): void {
        this.httpSubjectService.notificationSubject.subscribe({
            next: (json: any) => {
                console.log("Call Notification Service");
            }
        });
    }

    private httpRedirects(): void {
        this.httpSubjectService.http500Subject.subscribe({
            next: (error: any) => {
                console.log("Navigate to Error Page");
            }
        });

        this.httpSubjectService.http403Subject.subscribe({
            next: (error: any) => {
                console.log("Navigate to Not Authorized Page");
            }
        });
    }
}


class AppLocalsModel {
    public username : string = "noch nicht abgefragt";
}

SINCE ANGULAR 4.3你可以使用InterCeptors

在Angular 4.3中你有本机拦截器，你可以实现自己的东西，比如重定向服务器错误500

import { Injectable } from '@angular/core';
import { Router } from '@angular/router';
import { HttpInterceptor, HttpHandler, HttpRequest, HttpEvent, HttpResponse } from '@angular/common/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/do';
import 'rxjs/add/operator/catch';
import 'rxjs/add/observable/throw';

@Injectable()
export class SxpHttp500Interceptor implements HttpInterceptor {

  constructor(public router: Router) { }

  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
      return next.handle(req).do(evt => { }).catch(err => {
          if (err["status"]) {
              if (err.status === 500) {
                  this.router.navigate(['/serverError', { fehler: JSON.stringify(err) }]);
              }
          }
          return Observable.throw(err);
      });
  }
}

您需要在providers Array

中的核心模块中注册它

import { HTTP_INTERCEPTORS } from '@angular/common/http';
import { Router } from '@angular/router';
import { SxpHttp500Interceptor } from "./sxpHttp500.interceptor";
 ....

providers: [
    {
        provide: HTTP_INTERCEPTORS, useFactory: (router: Router) => { return new SxpHttp500Interceptor(router) },
        multi: true,
        deps: [Router]
    }
]

Answer 5

使用Angular 4.3.1版本，现在有一个名为 HttpInterceptor 的接口。

这是指向文档的链接： https://angular.io/api/common/http/HttpInterceptor

这是一个实施示例。

这将是拦截器类实现。

基本上写成任何其他服务：

@Injectable()
export class ExceptionsInterceptor implements HttpInterceptor {
    constructor(
        private logger: Logger,
        private exceptionsService: ExceptionsService,
        private notificationsService: NotificationsService
    ) { }
    intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {

        return next.handle(request)
            .do((event) => {
                // Do nothing here, manage only errors
            }, (err: HttpErrorResponse) => {
                if (!this.exceptionsService.excludeCodes.includes(err.status)) {
                    if (!(err.status === 400 && err.error['_validations'])) {
                        this.logger.error(err);
                        if (!this.notificationsService.hasNotificationData(err.status)) {
                            this.notificationsService.addNotification({ text: err.message, type: MessageColorType.error, data: err.status, uid: UniqueIdUtility.generateId() });
                        }
                    }
                }
            });
    }
}

然后，由于您将此视为普通服务，因此您必须在应用模块的提供商中添加此行：

{ provide: HTTP_INTERCEPTORS, useClass: ExceptionsInterceptor, multi: true }

希望它可以提供帮助。

Answer 6

Angular 4.3 现在支持Http拦截器开箱即用。看看如何使用它们： https://ryanchenkie.com/angular-authentication-using-the-http-client-and-http-interceptors

Answer 7

我已经使用以下节点模块发布了拦截器。我们为内部目的创建了这个模块，最后我们在npm包管理器中发布了 npm install angular2-resource-and-ajax-interceptor 的 https://www.npmjs.com/package/angular2-resource-and-ajax-interceptor

Answer 8

正如@squadwuschel指出的那样，正在开展工作以将此功能引入@ angular / http。这将是一个新的HttpClient API的形式。

有关详细信息和当前状态，请参阅https://github.com/angular/angular/pull/17143。

Answer 9

尝试Covalent from Teradata，它们为Angular和Angular Material提供了许多扩展。

检查HTTP部分，它在Angular和RESTService中提供缺少的http拦截器（类似于restangular）。

我已在我的示例中通过 Covalent HTTP实施了JWT令牌身份验证，请点击此处。

https://github.com/hantsy/angular2-material-sample/blob/master/src/app/core/auth-http-interceptor.ts

请阅读我的开发说明，Handle token based Authentication via IHttpInterceptor。

Answer 10

Angular2 donot支持像angular1

这样的httpinterceptor

这是在angular2中使用httpinterceptor的一个很棒的例子。

https://github.com/NgSculptor/ng2HttpInterceptor

在angular2中，httpinterceptor等价是什么？

10 个答案:

这是一个实施示例。

这将是拦截器类实现。