$ asyncValidators Angular

Question

我正在使用Angular 1.3.*,我尝试验证我的表单.它在ng-repeat内.所以我可能会获得几个输入字段.我不仅要求字段不为空,而且还要求从后端检索信息时搜索成功.

我有这个输入字段

                               <input type="text"
                               ng-model="user"
                               placeholder="username"
                               name="user{{$index}}"
                               typeahead="data as data.name for data in getUser($viewValue)"
                               typeahead-editable="false"
                               class="form-control"
                               autocomplete="off"
                               userValidator
                               required>
<div ng-if="myForm.$submitted" ng-messages="myForm.user{{$index}}.$error ">
                          <div ng-message="required">You need to type something</div>
                        </div>

                        <div ng-if="myForm.$submitted" ng-messages="myForm.user{{$index}}.$error">
                          <div ng-message="userValidator"> It seems that the entered user is           not a valid input</div>
                        </div>

这是我对后端呼叫​​的尝试

  .directive('userValidator',function($http,$q){
    return{
      require:'ngModel',
      link:function($scope,element,attrs,ngModel){
        ngModel.$asyncValidators.userAvailable=function(userInput){
          return $http.post('/user'+userInput)
            .then(function)????

        }
      }
    }
  });

请注意,我希望用户存在.我想我必须使用asyncValidators进行后端调用.但是,我似乎没有得到它.对我来说,避免这种情况的一种方法是,在所有其他$错误而不是"必需"上,显示消息"似乎输入的用户不是有效输入".我怎样才能成功地进行后端呼叫并使用它,或者我怎样才能确保在所有其他场合显示其他错误消息？

Answer 1

如果用户名存在,则只返回true,如果不存在,则直接拒绝该消息

.directive('userValidator',function($http,$q){
return{
  require:'ngModel',
  link:function($scope,element,attrs,ngModel){
    ngModel.$asyncValidators.userAvailable = function(modelValue , viewValue) {

     var userInput= modelValue || viewValue;
      return $http.post('/user'+userInput)
         .then(function() {
           //username exists, this means validation success
           return true;
         }, function() {
           //username does not exist, therefore this validation fails
           return $q.reject('selected username does not exists');
         });

      }
    }
  }
});