A service that securely provides Xirsys app tokens to a WebRTC client via PubNub Functions

xirsys-pfunc-endpoint.js

const pubnub = require('pubnub');
const kvstore = require('kvstore');
const xhr = require('xhr');
const vault = require('vault');
const base64Codec = require('codec/base64');

// If you are still developing, set the permittedOrigin to * and remove the check on line 15
const permittedOrigin = 'https://your-website-origin.com';
const xirsysChannel = 'your-xirsys-channel-name';

export default (request, response) => {
    response.headers['Access-Control-Allow-Origin'] = permittedOrigin;
    response.headers['Access-Control-Allow-Headers'] = 'Origin, X-Requested-With, Content-Type, Accept';
    
    if (request.headers.origin !== permittedOrigin) {
        response.status = 401;
        return response.send();
    }

    if (request.method.toUpperCase() === 'GET') {
        const uuid = newUuid() + newUuid() + newUuid() + newUuid();
        const tok = base64Codec.encodeString(uuid);
        
        return kvstore.set(tok, true, 60).then(() => {
            response.status = 200;
            return response.send(tok);
        });
        
    } else if (request.method.toUpperCase() === 'PUT') {
        if (!request.headers.tok) {
            response.status = 401;
            return response.send();
        }
        
        return kvstore.get(request.headers.tok).then((validTok) => {
            if (!validTok) {
                console.error('invlaidtok', request.headers.tok);
                response.status = 401;
                return response.send();
            }
            
            return vault.get('xirsys').then((xirsysCredential) => {
                const xirsysEndpoint = `https://${xirsysCredential}@global.xirsys.net/_turn/${xirsysChannel}`;
                return xhr.fetch(xirsysEndpoint, { 'method': 'PUT' })
                .then((res) => {
                    let rtcObj = flatten(JSON.parse(res.body).v);
                    response.status = 200;
                    return response.send(rtcObj);
                }).catch((err) => {
                    console.error(err);
                    response.status = 400;
                    return response.send();
                });
            });
        });
    } else {
        response.status = 401;
        return response.send();
    }
};

function newUuid() {
  function s4() {
    return Math.floor((1 + Math.random()) * 0x10000)
      .toString(16)
      .substring(1);
  }
  return s4() + s4() + '-' + s4() + '-' + s4() + '-' + s4() + '-' + s4() + s4() + s4();
}

function flatten(rtc) {
    let newcred = { urls: [] };

    rtc.iceServers.forEach((obj) => {
        newcred.urls.push(obj.url);
        newcred.username = obj.username;
        newcred.credential = obj.credential;
    });
    return newcred;
}