angularjs $resource : can't $save JSON - rest

Question

starting with angular, i am trying to GET data from the server and then POST back modifications with $resources.
It's working fine except the "save" function. No Data is POSTed back to the server.
here is the html
<div ng-controller="myCtrl">
<div ng-repeat="obj in objs">
<h2>{{obj.data_1}}</h2>
<h3>{{obj.data_2}}</h3>
<input type='text' ng-model="obj.data_1"><br/>
<textarea ng-model="obj.data_2" required></textarea><br/>
<button ng-click="save()">Save</button>
</div>
</div>
service.js
'use strict';
angular.module('App.services', ['ngResource']).
factory('Obj', function($resource){
return $resource('url/to/json');
});
controller.js:
'use strict';
angular.module('App.controllers', []).
controller('myCtrl', ['$scope', 'Obj', function($scope, Obj) {
$scope.objs = Obj.query();
$scope.save = function() {
$scope.objs.save();
}
}]);
Do you know why nothing is POSTed back when i save ?

Answer 1

Using the query method on the $resource object implies return as follows 'query': {method:'GET', isArray:true} it's mean that your $scope.objs is an array of objects and not an object and depending on number of elements you can use the folowing notation:
$scope.objs[i].save()
where i is the index of element in the array, forexample if you have return like:
[ {id:1, name:'Some name', age:35} ];
then your code : $scope.objs[0].save()
Edit:
I have created a plunk, maybe it will help you... http://plnkr.co/edit/62iPCAUNjV0oJROhul1G

Answer 2

Shouldn't there be another $resource declared for POST the way it is declared for GET? Each $resource specify particular REST service.
//services.js
'use strict';
angular.module('App.services', ['ngResource'])
.factory('GetObj', function($resource){
return $resource('url/to/json');
}
.factory('SaveObj', function($resource){
return $resource('url/to/post');
});
//controller.js
'use strict';
angular.module('App.controllers', []).
controller('myCtrl', ['$scope', 'GetObj', 'SaveObj', function($scope, GetObj, SaveObj) {
$scope.objs = Obj.query();
$scope.save = SaveObj.save(objs, function(resp) {
//Callback
console.log("Response from POST: %j", resp);
}
}]);