AngularJS Scope Doesn't Update After New Request -

i'm new angularjs still have been reading lot of material , started test out things learning. i'm trying write code uses service reaches last.fm api , returns list of similar artists. i'm returning result fine api , can see results if send them console. said, after 1 search subsequent searches don't update scope properly. code follows:

controller

.controller('lastfmcontroller', function($scope, lastfm) {     $scope.search = function(artist) {         lastfm.getsimilar(artist).then(function(result) {             $scope.artists = result.similarartists.artist;         }, function(error) {             $scope.error = error;         });     }; }); 

view

<form role="form"> <div class="form-group">     <label for="artist">search music artist , see similiar artists</label>     <input type="text" name="artist" class="form-control" ng-model="artist" placeholder="type artist's name"> </div> <button type="submit" class="btn btn-default" ng-click="search(artist)">search</button> </form>  <hr ng-if="artists" />  <div class="row">     <div class="col-sm-6 col-md-4 fade in" ng-repeat="artist in artists">         <h3>{{ artist.name }}</h3>         <p><a target="_blank" href="http://{{ artist.url }}" class="btn btn-primary" role="button">view on last.fm</a></p>     </div> </div> 

service

.factory('lastfm', function($q, $http) {     var deferred = $q.defer(),         self = this,         apikey = "key";      return {         getsimilar: function(artist) {             this.url = 'http://ws.audioscrobbler.com/2.0/?method=artist.getsimilar&artist=' + artist + '&api_key=' + apikey + '&format=json&autocorrect=1';             this.error = false;              $http.get(this.url).success(function(data) {                 if (data.error) {                     deferred.reject(data.error.message);                 }                 else if (!angular.isundefined(data.similarartists) && angular.isobject(data.similarartists.artist)) {                 deferred.resolve(data);                 }                 else {                     deferred.reject('something went wrong');                 }             });              return deferred.promise;         }     }; }); 

as said, when initial search result displays, subsequent searches don't update scope. tried $scope.$apply said running command. ideas?

in factory, define deferred. deferred resolved on first call getsimilar, not on each call (because factories singletons). furthermore, don't need deferred because $http returns promise itself. remove deferred initialization in factory, , return $http call in getsimilar. if need deferred, initalize inside getsimilar.