angularjs+python(Flask) file upload to server

I am developing a web app using angular, python and Flask. In my app there is a form where the user need to enter some data and to upload his photo. I want to implement the file upload to the server using angular. I saw that I need to use the FormData() and to bind the data from the HTML to angular using "watch". The javascript part is clear. I don't understand how can I get the data from the Python side.

This is my HTML -

<form  enctype="multipart/form-data" ng-submit="submitGuideDetailsForm()">
  <div class="form-group">
    <label for="usr">Add your photo:</label>
    <input type='file' class="form-control" name='file' onchange="angular.element(this).scope().uploadFile(this.files)">
  </div>
</form>

This is my angular -

 $scope.uploadFile = function(files) {
            $scope.file = new FormData();
            $scope.file.append("file", files[0]);
        };
 $scope.submitGuideDetailsForm= function() {
     $http.post('/uploadFile', $scope.file, {
           headers: {'Content-Type': undefined },
           transformRequest: angular.identity
          }).success(function(results) 
           {   
              $log.log('success load file')
           }).error(function(error) 
           {
              $log.log('error load file!!!!!')
              $log.log(error);
           });
       };

I want to get the file on the server side, using python and flask -

@app.route('/uploadFile', methods=['POST'])
def uploadFile():
  json_data = request.json
  print(json_data)
  status = 'success'
  return jsonify({'result': status})

I don't know how to get the data from the 'request' object. request.json does not work.

Please advice me what am I doing wrong. How can I get the data from the 'request' object? Do I need to encode the data to a file? How do I send the data back to client? Do I need to encode it back? I did not find a full example using angular and python/flask uploading a file to server, saving it and than downloading it to the client. Thanks a lot, Dina