src/app/services/request-interceptor.service.ts

/*
******************************************************************************
* Copyright © 2018 PTA GmbH.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
*
*     http://www.eclipse.org/legal/epl-v10.html
******************************************************************************
 */
import { SessionContext } from './../common/session-context';
import { AuthenticationService } from './authentication.service';
import { MessageServiceCustom, MessageDefines } from './message.service';
import { Router } from '@angular/router';
import { Injectable } from '@angular/core';
import {
    HttpInterceptor,
    HttpRequest,
    HttpErrorResponse,
    HttpHandler,
    HttpEvent
} from '@angular/common/http';

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/do';

@Injectable()
export class RequestInterceptor implements HttpInterceptor {


    constructor(private msgService: MessageServiceCustom,
        private authService: AuthenticationService,
        private router: Router,
        private sessionContext: SessionContext) { }

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

        return next
            .handle(request)
            .do((ev: HttpEvent<any>) => {
                // could do something with the resonse
                /* if (ev instanceof HttpResponse) {
                    console.log('Response:', ev);
                } */
            }).catch(error => {
                if (error instanceof HttpErrorResponse) {

                    // this.sessionContext.centralHttpResultCode$.emit(error.status);

                    if (error.status === 401) {
                        // redirect to the login route
                        // or show a modal
                        if (this.sessionContext.isUserAuthenticated()) {
                            this.msgService.loginLogoff$.emit(MessageDefines.MSG_LOG_OFF);
                            this.router.navigate(['/loggedout']);
                        }
                    } else if (error.status !== 302 && (error.status < 200 || error.status >= 300)) {
                        throw new Error('Bad response status: ' + error.status);
                    }
                }

                return Observable.throw(error);
            }

            );
    }
}