gistfile1.txt

(function () {
    'use strict';

    var core = angular.module('config');
    core.config(configure);
    configure.$inject = ['$httpProvider'];

    /* @ngInject */
    function configure($httpProvider) {

        //Intercept all http requests
        $httpProvider.interceptors.push(['$injector', '$q', "AuthorizationTokenService", function ($injector, $q, AuthorizationTokenService) {
            var cachedRequest = null;
            return {
                request: function (config) {  
                    //If request is for refreshToken pass it without Authorization header
                    if(config.url.indexOf("refreshToken") !== -1) {
                        return config;
                    }
                    //If request if for API attach Authorization header with Access Token
                    else if (config.url.indexOf("api") != -1) {
                        var accessToken = AuthorizationTokenService.getLocalAccessToken();
                        config.headers['Authorization'] = 'Bearer ' + accessToken;
                    }
                    return config;
                },
                responseError: function (response) {
                    switch (response.status) {
                    //Detect if reponse error is 401 (Unauthorized)
                        case 401:
                            //Cache this request
                            var deferred = $q.defer();
                            if(!cachedRequest) {
                                //Cache request for renewing Access Token and wait for Promise
                                cachedRequest = AuthorizationTokenService.refreshAccessToken();
                            }
                            //When Promise is resolved, new Access Token is returend 
                            cachedRequest.then(function(accessToken) {
                                cachedRequest = null;
                                if (accessToken) {
                                //Resend this request when Access Token is renewed
                                    $injector.get("$http")(response.config).then(function(resp) {
                                        //Resolve this request (successfully this time)
                                        deferred.resolve(resp);
                                    },function(resp) {
                                        deferred.reject();
                                    });
                                } else {
                                    //If any error occurs reject the Promise
                                    deferred.reject();
                                }
                            }, function(response) {
                                //If any error occurs reject the Promise
                                cachedRequest = null;
                                deferred.reject();
                                return;
                            });
                            return deferred.promise;
                    }
                    //If any error occurs reject the Promise
                    return $q.reject(response);
                }
            };
        }]);
    }
})();