错误：流意外结束

Question

使用ng-file-upload将照片从前端发送到服务器端这是我的代码：

查看：

<form name="photoForm" ng-submit="uploadPicture(files)">
    <input type="text" class="form-control" value="Add Caption" ng-model="caption">
    <input type="button" name="files" value="Upload picture" ngf-select ng-model="files" ngf-multiple="true" ngf-pattern="'image/*'">
    <input type="submit" class="btn btn-default submitButton" ng-disabled="!photoForm.$valid">
    <ul>
      <li ng-repeat="f in files" style="font:smaller">
        {{f.name}}{{f.$errorParam}}
      </li>
    </ul> </form

控制器：

// Upload Image
$scope.uploadPicture = function(files){

  if (files && files.length) {
      $scope.uploadFiles(files);
  }
};

$scope.uploadFiles = function(files){
   Upload.upload({
    url: '/api/posts/photo',
    method: 'POST',
    file: files
  }).then(function (response) {
        $timeout(function () {
            $scope.result = response.data;
        });
    }, function (response) {
        if (response.status > 0) {
            $scope.errorMsg = response.status + ': ' + response.data;
        }
    });
};

路线：

var  multipart = require('connect-multiparty'),
     multipartMiddleware = multipart();

app.route('/api/posts/photo')
      .post(multipartMiddleware, photos.create);

服务器：

exports.create = function(req, res){

  console.log(req.body, req.files);
};

什么时候我的console.log（req.files），没有multipartMiddleware我能够看到我上传的文件，但是一旦我添加了multipartMiddleware，错误信息就会显示出来。