interceptor

import { Injectable } from '@angular/core'  
import { HttpInterceptor, HttpHandler, HttpRequest, HttpEvent, HttpResponse } from '@angular/common/http';  
import { Observable } from 'rxjs/Observable';  
import 'rxjs/add/operator/do';  
  
@Injectable()  
export class HeaderInterceptor implements HttpInterceptor {  
    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {  
         
        const dummyrequest = req.clone({  
            setHeaders: {  
                'AuthKey': '12345', 'DeviceID': '85645',  
                'content-type': 'application/json'  
            }  
        })  
        console.log("Cloned Request");   
        console.log(dummyrequest);   
        return next.handle(dummyrequest);  
    }  
}