client/src/app/shared/auth/auth-interceptor.service.ts

   1 import { Injectable, Injector } from '@angular/core'
   2 import {
   3   HttpInterceptor,
   4   HttpRequest,
   5   HttpEvent,
   6   HttpHandler, HTTP_INTERCEPTORS
   7 } from '@angular/common/http'
   8 import { Observable } from 'rxjs/Observable'
   9
  10 import { AuthService } from '../../core'
  11 import 'rxjs/add/operator/switchMap'
  12
  13 @Injectable()
  14 export class AuthInterceptor implements HttpInterceptor {
  15   private authService: AuthService
  16
  17   // https://github.com/angular/angular/issues/18224#issuecomment-316957213
  18   constructor (private injector: Injector) {}
  19
  20   intercept (req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
  21     if (this.authService === undefined) {
  22       this.authService = this.injector.get(AuthService)
  23     }
  24
  25     const authReq = this.cloneRequestWithAuth(req)
  26
  27     // Pass on the cloned request instead of the original request
  28     // Catch 401 errors (refresh token expired)
  29     return next.handle(authReq)
  30                .catch(err => {
  31                  if (err.status === 401) {
  32                    return this.handleTokenExpired(req, next)
  33                  }
  34
  35                  return Observable.throw(err)
  36                })
  37   }
  38
  39   private handleTokenExpired (req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
  40     return this.authService.refreshAccessToken()
  41                            .switchMap(() => {
  42                              const authReq = this.cloneRequestWithAuth(req)
  43
  44                              return next.handle(authReq)
  45                            })
  46   }
  47
  48   private cloneRequestWithAuth (req: HttpRequest<any>) {
  49     const authHeaderValue = this.authService.getRequestHeaderValue()
  50
  51     if (authHeaderValue === null) return req
  52
  53     // Clone the request to add the new header
  54     return req.clone({ headers: req.headers.set('Authorization', authHeaderValue) })
  55   }
  56 }
  57
  58 export const AUTH_INTERCEPTOR_PROVIDER = {
  59   provide: HTTP_INTERCEPTORS,
  60   useClass: AuthInterceptor,
  61   multi: true
  62 }