angular function call before html view is load - angularjs

Question

I am working on angularjs (1.6) and want to made a functionality in angular service, its call when a controller call and its service have an ajax code like
app.service('myServ', function($http, $window){
this.backdoor=function(){
$http({
method : 'get',
url : 'web_services/backdoor.php'
}).then(function(res){
// console.log(res.data);
// console.log(res.data.length);
if(res.data.length==0)
{
$window.location.href="index.html";
}
});
}});
and my controller code is :
app.controller('myCtrl', function($scope, $http, $window, myServ, $routeParams){
myServ.backdoor();
});
so the above code (service) is check a user session is created or not, but the problem is when session is not created on server side then my html page load for a second then server will call $window.location.href so please help me about the right way to do this....

Answer 1

I believe you need a resolve in angular.config. Its job is to run some code before you are being redirected to your route/state (for ngRoute or ui.router).
To do that you would need to have:
app.service('myServ', function($http, $window){
this.backdoor=function(){
return $http({ // return the promise if you need to use the values in the controller
method : 'get',
url : 'web_services/backdoor.php'
}).then(function(res){
if(res.data.length==0){ $window.location.href="index.html"; }
else{ return res.data; } // return the values
});
}});
and main part:
app.config(['$routeProvider', function($routeProvider) {
$routeProvider
.when('/your_page/:route_params', {
templateUrl: 'your_page_partial.html',
controller: 'myCtrl',
resolve: {
resolvedVal: function resMyService(myServ, $routeParams){ // setting an injectable instance `resolvedVal`
/* use $routeParams values as parameters? */
return myServ.backdoor(); // calling your service
}
}}
);
}]);
Then it's enough to just inject your resolve into the controller:
app.controller('myCtrl', function($scope, $http, $window, resolvedVal){ // note: resolvedVal injection
$scope.my_data = resolvedVal;
});