'Access-Control-Allow-Credentials' header in the response is '' which must be 'true'
angular, ecmascript-6, javascript, node.js
Solution
While setting cors in corsOptions I added value credentials true it worked as follows:
private setCors(){
let whitelist = ['http://localhost:4200','http://localhost:80'];
let corsOptions = {
origin: (origin:any, callback:any)=>{
if (whitelist.indexOf(origin) !== -1) {
callback(null, true)
} else {
callback(new Error('Not allowed by CORS'))
}
},credentials: true
}
this.app.use(cors(corsOptions));
}
Problem
I'm using node, express on backend and angular4 at client side which is giving me following error: XMLHttpRequest cannot load http://localhost:4876/login/check. Response to preflight request doesn't pass access control check: The value of the 'Access-Control-Allow-Credentials' header in the response is '' which must be 'true' when the request's credentials mode is 'include'. Origin 'http://localhost:4200' is therefore not allowed access. The credentials mode of requests initiated by the XMLHttpRequest is controlled by the withCredentials attribute. Api for login/check is implimented as below: ``` router.get('/login/check', (req: any, res: any) => { let api = new ApiConnection(req, res); let accessCard: IAccessCard = api.getContent(Auth.ACCESS_CARD_KEY); if(!Auth.isValid(accessCard)) return api.response.error(); ChatBox.auth.isExpired(accessCard, function (err:any, isExpired: boolean) { if (err) return api.response.error(); if(!isExpired) { api.cookie("AccessCard", accessCard); api.response.success(accessCard); } else { api.response.error(); } }) }); ``` Where router definition is `const router = require('express').Router()` Setting middleware for header and cors is as follows: ``` export class Application { private app:any = express(); constructor() { this.setCors(); this.setHeaders(); } public getApp():any { return this.app; } private setCors(){ let whitelist = ['http://localhost:4200','http://localhost:80']; let corsOptions = { origin: (origin:any, callback:any)=>{ if (whitelist.indexOf(origin) !== -1) { callback(null, true) } else { callback(new Error('Not allowed by CORS')) } } } this.app.use(cors(corsOptions)); } private setHeaders() { this.app.use(function (req:any, res:any, next: any) { // Website you wish to allow to connect //res.setHeader('Access-Control-Allow-Origin', Config.WEB_APP_HOST); res.setHeader('Access-Control-Allow-Origin', 'http://localhost:4200'); // Request methods you wish to allow res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE'); // Request headers you wish to allow res.setHeader('Access-Control-Allow-Headers', 'X-Requested-With, content-type'); // Set to true if you need the website to include cookies in the requests sent // to the API (e.g. in case you use sessions) res.setHeader('Access-Control-Allow-Credentials', true); // Pass to next layer of middleware next(); }); } } ``` On client side I'm using Api as follows: ``` public startSession(callback: (status: boolean, result: any) => void ) { let self: ChatBox = this; /** * @res.result: IAccessCard */ this.mApiConnection.get(Api.root+'/login/check', (res: any) => { if (res.status == ResponseStatus.SUCCESS) { self.mStorage.storeAccessCard(res.result); self.loadAccount(res.result); } callback(res.status, res.result); }) } ```