import{Injectable,Inject,PLATFORM_ID}from'@angular/core';import{HttpEvent,HttpInterceptor,HttpHandler,HttpRequest,HttpResponse,HttpErrorResponse,HttpEventType}from'@angular/common/http';import{Observable}from'rxjs/Observable';import{TransferState}from'./../modules/transfer-state/transfer-state';import{isPlatformServer}from'@angular/common';import{ORIGIN_URL}from'./shared/constants/baseurl.constants';@Injectable()exportclassCustomHttpInterceptorimplementsHttpInterceptor{privateisServer=isPlatformServer(this.platformId);constructor(        @Inject(PLATFORM_ID)privateplatformId,protectedtransferState:TransferState,        @Inject(ORIGIN_URL)privatebaseUrl:string){}intercept(req:HttpRequest<any>,next:HttpHandler):Observable<HttpEvent<any>>{letmodifiedRequest:any;leturl:string;letisLocalRequest:boolean=!req.url.startsWith('http');if(isLocalRequest){url=(isLocalRequest ?this.baseUrl+req.url :req.url);// Skip cache check if the request method isn't GET.if(req.method=='GET'){constcachedResponse=this.getFromCache(url);if(cachedResponse){// A cached response exists. Serve it instead of forwarding// the request to the next handler.letmodifiedResponse=newHttpResponse<any>({headers:cachedResponse.headers,body:cachedResponse.body,status:cachedResponse.status,statusText:cachedResponse.statusText,url:cachedResponse.url});returnObservable.of(modifiedResponse);}}// Clone the request to add the new header.modifiedRequest=req.clone({headers:req.headers,url:url,body:req.body});}returnnext.handle(isLocalRequest ?modifiedRequest :req).do((event:HttpEvent<any>)=>{if(eventinstanceofHttpResponse){if(this.isServer){this.setCache(url,event);}}});}privatesetCache(key,data){returnthis.transferState.set(key,data);}privategetFromCache(key):HttpResponse<any>|null{returnthis.transferState.get(key);}}

import { Injectable, Inject, PLATFORM_ID } from '@angular/core';import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest, HttpResponse, HttpErrorResponse, HttpEventType } from '@angular/common/http';import { Observable } from 'rxjs/Observable';import { TransferState } from '@angular/platform-browser';import { isPlatformServer } from '@angular/common';import { ORIGIN_URL } from './shared/constants/baseurl.constants';@Injectable()export class CustomHttpInterceptor implements HttpInterceptor {    private isServer = isPlatformServer(this.platformId);    constructor(        @Inject(PLATFORM_ID) private platformId,        protected transferState: TransferState,        @Inject(ORIGIN_URL) private baseUrl: string) { }    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {        let modifiedRequest: any;        let url: string;        let isLocalRequest: boolean = !req.url.startsWith('http');        if (isLocalRequest) {            url = this.baseUrl + req.url;            // Skip cache check if the request method isn't GET.            if (req.method == 'GET') {                const cachedResponse = this.getFromCache(url);                if (cachedResponse) {                    // A cached response exists. Serve it instead of forwarding                    // the request to the next handler.                    let modifiedResponse = new HttpResponse<any>({ headers: cachedResponse.headers, body: cachedResponse.body, status: cachedResponse.status, statusText: cachedResponse.statusText, url: cachedResponse.url });                    return Observable.of(modifiedResponse);                }            }            // Clone the request to add the new header.            modifiedRequest = req.clone({ headers: req.headers, url: url, body: req.body });        }        return next.handle(isLocalRequest ? modifiedRequest : req)            .do((event: HttpEvent<any>) => {                if (event instanceof HttpResponse) {                    if (this.isServer) {                        this.setCache(url, event);                    }                }            });    }    private setCache(key, data) {        return this.transferState.set(key, data);    }    private getFromCache(key): HttpResponse<any> | null {        return this.transferState.get(key, null as any);    }}

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