Angularjs在每个routeChange之前运行XHR请求，而不管控制器是什么

Question

I am working on a new project, and on the first phase, I would like to check if the user has a session with the server by sending an XHR HEAD request to /api/me.

I would like to use the following syntax

$rootScope.$on("$routeChangeStart", function(event, current, previous, rejection){/*...*/})

The problem is that I don't want to rewrite this code per each controller, is there any way to do this in a generic way?, .run?, service(factory), which way is the correct one?.

please provide a brief smaple of code as I am a total newbie to this framework.

var app = angular.module('home', []);
var httpConfig = {withCredentials: true};
app.config(function($routeProvider){
$routeProvider.
when('/', 
    {
        template: 'views/home.html', 
        controller: homeCtrl 
    }).
when('/login', 
    {
        template: 'views/login.html', 
        controller: loginCtrl 
    }).
when('/logout', 
    {
        template: 'views/logout.html',
        controller: logoutCtrl

    }).
otherwise(
    {   
        template: 'views/home.html', 
        controller: homeCtrl
    })
}).
run(function($rootScope, authUser){
    $rootScope.$on('$routeChangeStart', function () {
        authUser($rootScope);
    })
}).
factory('authUser', function($http, httpConfig){
    var promise = $http.head('/users/me', httpConfig);
})

Answer 1

You can try using $routeProvider resolve as below:

app.config(function($routeProvider){
$routeProvider.
 when('/', 
{
    template: 'views/home.html', 
    controller: homeCtrl,
    resolve:{auth:"authUser"}
}).
when('/login', 
{
    template: 'views/login.html', 
    controller: loginCtrl ,
    resolve:{auth:"authUser"}
}).
when('/logout', 
{
    template: 'views/logout.html',
    controller: logoutCtrl,
    resolve:{auth:"authUser"}

})

Also you might need to change your factory function to return the promise:

app.factory('authUser', function($http, httpConfig){
    return $http.head('/users/me', httpConfig);
})