从Angular 4.3开始，HTTP拦截器现在可以通过新的HttpClient @angular/common/ HTTP使用了。X版本及更高版本。

现在为每个请求添加头文件非常简单:

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

@Injectable()
export class AddHeaderInterceptor implements HttpInterceptor {
  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    // Clone the request to add the new header
    const clonedRequest = req.clone({ headers: req.headers.append('Authorization', 'Bearer 123') });

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

有一个不可变性的原则，这就是为什么在设置新内容之前需要克隆请求。

由于编辑头部是一个非常常见的任务，实际上有一个快捷方式(在克隆请求时):

const clonedRequest = req.clone({ setHeaders: { Authorization: 'Bearer 123' } });

创建拦截器之后，你应该使用HTTP_INTERCEPTORS提供的方法注册它。

import { HTTP_INTERCEPTORS } from '@angular/common/http';

@NgModule({
  providers: [{
    provide: HTTP_INTERCEPTORS,
    useClass: AddHeaderInterceptor,
    multi: true,
  }],
})
export class AppModule {}

您可以使用拦截器，而不是为每个请求一次又一次地设置报头。

每个发出的请求都会经过拦截器，在拦截器中你可以设置你的认证头，然后释放请求。

我已经能够选择一个更简单的解决方案>添加一个新的头到默认选项合并或加载你的api得到(或其他)函数。

get(endpoint: string, params?: any, options?: RequestOptions) {
  if (!options) {
    options = new RequestOptions();
    options.headers = new Headers( { "Accept": "application/json" } ); <<<<
  }
  // [...] 
}

当然，你可以在默认选项或类中具体化这个头。 这是Ionic生成的api。ts @Injectable()导出类API {}

这是非常快的，它为我工作。我不想要json/ld格式。

你可以在你的路由中使用canActive，如下所示:

import { Injectable } from '@angular/core';
import { Router } from '@angular/router';
import { CanActivate } from '@angular/router';
import { AuthService } from './auth.service';

@Injectable()
export class AuthGuard implements CanActivate {

  constructor(private auth: AuthService, private router: Router) {}

  canActivate() {
    // If user is not logged in we'll send them to the homepage 
    if (!this.auth.loggedIn()) {
      this.router.navigate(['']);
      return false;
    }
    return true;
  }

}

const appRoutes: Routes = [
  {
    path: '', redirectTo: '/deals', pathMatch: 'full'
  },
  {
    path: 'special',
    component: PrivateDealsComponent,
    /* We'll use the canActivate API and pass in our AuthGuard.
       Now any time the /special route is hit, the AuthGuard will run
       first to make sure the user is logged in before activating and
       loading this route. */
    canActivate: [AuthGuard]
  }
];

摘自:https://auth0.com/blog/angular-2-authentication

这就是我如何为每个请求设置令牌。

import { RequestOptions, BaseRequestOptions, RequestOptionsArgs } from '@angular/http';

export class CustomRequestOptions extends BaseRequestOptions {

    constructor() {
        super();
        this.headers.set('Content-Type', 'application/json');
    }
    merge(options?: RequestOptionsArgs): RequestOptions {
        const token = localStorage.getItem('token');
        const newOptions = super.merge(options);
        if (token) {
            newOptions.headers.set('Authorization', `Bearer ${token}`);
        }

        return newOptions;
    }
}

并在app.module.ts中注册

@NgModule({
    declarations: [
        AppComponent
    ],
    imports: [
        BrowserModule
    ],
    providers: [
        { provide: RequestOptions, useClass: CustomRequestOptions }
    ],
    bootstrap: [AppComponent]
})
export class AppModule { }

你可以用一些授权头创建你自己的http客户端:

import {Injectable} from '@angular/core';
import {HttpClient, HttpHeaders} from '@angular/common/http';

@Injectable({
  providedIn: 'root'
})
export class HttpClientWithAuthorization {

  constructor(private http: HttpClient) {}

createAuthorizationHeader(bearerToken: string): HttpHeaders {
  const headerDict = {
    Authorization: 'Bearer ' + bearerToken,
  }
  return new HttpHeaders(headerDict);
}

get<T>(url, bearerToken) {
  this.createAuthorizationHeader(bearerToken);
  return this.http.get<T>(url, {
    headers: this.createAuthorizationHeader(bearerToken)
  });
}

post<T>(url, bearerToken, data) {
  this.createAuthorizationHeader(bearerToken);
  return this.http.post<T>(url, data, {
    headers: this.createAuthorizationHeader(bearerToken)
  });
}
}

然后在你的服务类中注入它而不是HttpClient:

@Injectable({
  providedIn: 'root'
})
export class SomeService {

  constructor(readonly httpClientWithAuthorization: HttpClientWithAuthorization) {}

  getSomething(): Observable<Object> {
    return this.httpClientWithAuthorization.get<Object>(url,'someBearer');
  }

  postSomething(data) {
    return this.httpClientWithAuthorization.post<Object>(url,'someBearer', data);
  }
}