Directiva de Angular.js para Input File y Ajax

ngUpload.js

// Bootstrap is used for visual effects

/*
 HTML
 <ng-upload ng-model="file"></ng-upload>  
 <ng-upload ng-model="Object.file"></ng-upload>
*/

var directives = {
  ngUpload: function () {
    return {
      require: '?ngModel',
      restrict: 'E',
      template: '<input type="file" class="form-control btn btn-primary">',
      link: function(scope, element, attrs, ngModel) {

        if (!ngModel) return;

        var model = attrs.ngModel;
        scope.$watch(model, function (newValue, oldValue) {

          if(newValue == null && oldValue != null){
            element.children().remove();
            element.append('<input type="file" class="form-control btn btn-primary">');

          element.children().bind('change', function (event){
            var file = event.target.files[0];
            if(!(typeof(file) === "undefined")){   
              // Filter file types
              if(file.type == 'application/pdf'){
                element.children().removeClass('btn-primary');
                element.children().removeClass('btn-danger');
                element.children().addClass('btn-success');
                scope.$apply(function() {
                  ngModel.$setViewValue(file);
                });
              }else{
                element.children().removeClass('btn-primary');
                element.children().removeClass('btn-success');
                element.children().addClass('btn-danger');
                scope.$apply(function() {
                  ngModel.$setViewValue(null);
                });
              }
            }
          });

          }
        })

        element.children().bind('change', function (event){
          var file = event.target.files[0];
          if(!(typeof(file) === "undefined")){   
            // Filter file types
            if(file.type == 'application/pdf'){
              element.children().removeClass('btn-primary');
              element.children().removeClass('btn-danger');
              element.children().addClass('btn-success');
              scope.$apply(function() {
                ngModel.$setViewValue(file);
              });
            }else{
              element.children().removeClass('btn-primary');
              element.children().removeClass('btn-success');
              element.children().addClass('btn-danger');
              scope.$apply(function() {
                ngModel.$setViewValue(null);
              });
            }
          }
        });

      }
    };
  }
}

/* HTTP Request Ajax */
 http({
   headers: { 'Content-Type': undefined },
   transformRequest: function (data) {
     var formData = new FormData();
     var obj_ = angular.toJson(data.obj);
     delete obj_.file 
     formData.append('obj', obj_);
     formData.append('file', data.obj.file);
     return formData;
   },
   method: 'POST',
   // method: 'PUT',
   url: '/foo',
   // data: { file: file }
   data: { obj: obj }
 });

app.directive(directives);