Django REST Framework上傳圖片：“提交的數據不是文件”

Question

我傾向於如何在Django中上傳文件，在這里我遇到一個應該是微不足道的問題，錯誤：

提交的數據不是文件。 檢查表單上的編碼類型。

以下是詳細信息。

---

注意：我也看了Django Rest Framework ImageField ，我試過了

serializer = ImageSerializer(data=request.data, files=request.FILES)

但我明白了

TypeError： __init__()得到了一個意外的關鍵字參數'files'

---

我有一個Image模型，我想通過Django REST框架與之交互：

models.py

class Image(models.Model):
    image = models.ImageField(upload_to='item_images')
    owner = models.ForeignKey(
        User, related_name='uploaded_item_images',
        blank=False,
    )
    time_created = models.DateTimeField(auto_now_add=True)

serializers.py

class ImageSerializer(serializers.ModelSerializer):
    image = serializers.ImageField(
        max_length=None, use_url=True,
    )

    class Meta:
        model = Image
        fields = ("id", 'image', 'owner', 'time_created', )

settings.py

'DEFAULT_PARSER_CLASSES': (
    'rest_framework.parsers.JSONParser',
    'rest_framework.parsers.FormParser',
    'rest_framework.parsers.MultiPartParser',
),

前端（使用AngularJS和angular-restmod或$resource ）使用表單的owner和image發送JSON數據：

輸入：

{"owner": 5, "image": "data:image/jpeg;base64,/9j/4QqdRXhpZgAATU0A..."}

在后端， request.data顯示

{u'owner': 5, u'image': u'data:image/jpeg;base64,/9j/4QqdRXhpZgAATU0AKgAAA..."}

但是然后ImageSerializer(data=request.data).errors顯示錯誤

ReturnDict([('image', [u'The submitted data was not a file. Check the encoding type on the form.'])])

我想知道我應該怎么做才能解決這個錯誤？

---

編輯：JS部分

相關的前端代碼由兩部分組成：一個angular-file-dnd directive （ 此處可用）將文件放到頁面上， angular-restmod提供CRUD操作：

<!-- The template: according to angular-file-dnd, -->
<!-- it will store the dropped image into variable $scope.image -->
<div file-dropzone="[image/png, image/jpeg, image/gif]" file="image" class='method' data-max-file-size="3" file-name="imageFileName">
  <div layout='row' layout-align='center'>
    <i class="fa fa-upload" style='font-size:50px;'></i>
  </div>
  <div class='text-large'>Drap & drop your photo here</div>
</div>



# A simple `Image` `model` to perform `POST`
$scope.image_resource = Image.$build();

$scope.upload = function() {
  console.log("uploading");
  $scope.image_resource.image = $scope.image;
  $scope.image_resource.owner = Auth.get_profile().user_id;
  return $scope.image_resource.$save();
};

---

---

關於這個問題的更新：現在我切換到使用ng-file-upload ，它以適當的格式發送圖像數據。

Answer 1

您遇到的問題是Django REST框架希望通過標准文件上載方法將文件作為多部分表單數據上載。 這通常是file字段 ，但JavaScript Blob對象也適用於AJAX。

您希望使用base64編碼的字符串上載文件，而不是默認情況下不支持的原始文件。 有一個Base64ImageField實現 ，但最有希望的是一個pull請求 。

由於這些主要是為Django REST框架2.x設計的，因此我對pull請求中的那個進行了改進，並創建了一個應該與DRF 3兼容的應用程序。

serializers.py

from rest_framework import serializers    

class Base64ImageField(serializers.ImageField):
    """
    A Django REST framework field for handling image-uploads through raw post data.
    It uses base64 for encoding and decoding the contents of the file.

    Heavily based on
    https://github.com/tomchristie/django-rest-framework/pull/1268

    Updated for Django REST framework 3.
    """

    def to_internal_value(self, data):
        from django.core.files.base import ContentFile
        import base64
        import six
        import uuid

        # Check if this is a base64 string
        if isinstance(data, six.string_types):
            # Check if the base64 string is in the "data:" format
            if 'data:' in data and ';base64,' in data:
                # Break out the header from the base64 content
                header, data = data.split(';base64,')

            # Try to decode the file. Return validation error if it fails.
            try:
                decoded_file = base64.b64decode(data)
            except TypeError:
                self.fail('invalid_image')

            # Generate file name:
            file_name = str(uuid.uuid4())[:12] # 12 characters are more than enough.
            # Get the file name extension:
            file_extension = self.get_file_extension(file_name, decoded_file)

            complete_file_name = "%s.%s" % (file_name, file_extension, )

            data = ContentFile(decoded_file, name=complete_file_name)

        return super(Base64ImageField, self).to_internal_value(data)

    def get_file_extension(self, file_name, decoded_file):
        import imghdr

        extension = imghdr.what(file_name, decoded_file)
        extension = "jpg" if extension == "jpeg" else extension

        return extension

這應該用於替換Django REST框架提供的標准ImageField 。 所以你的序列化器會成為

class ImageSerializer(serializers.ModelSerializer):
    image = Base64ImageField(
        max_length=None, use_url=True,
    )

    class Meta:
        model = Image
        fields = ("id", 'image', 'owner', 'time_created', )

這應該允許您指定base64編碼的字符串，或Django REST框架通常期望的標准Blob對象。

Answer 2

幾天前我遇到了同樣的問題。 這是我的django rest框架視圖來處理文件上傳

views.py

class PhotoUploadView(APIView):
    parser_classes = (FileUploadParser,)

    def post(self, request):
        user = self.request.user
        if not user:
            return Response(status=status.HTTP_403_FORBIDDEN)
        profile  = None
        data     = None
        photo    = None

        file_form = FileUploadForm(request.POST,request.FILES)
        if file_form.is_valid():
            photo = request.FILES['file']
        else:
            return Response(ajax_response(file_form),status=status.HTTP_406_NOT_ACCEPTABLE)

        try:
            profile = Organizer.objects.get(user=user)
            profile.photo = photo
            profile.save()
            data    = OrganizersSerializer(profile).data
        except Organizer.DoesNotExist:
            profile = Student.objects.get(user=user)
            profile.photo = photo
            profile.save()
            data    = StudentsSerializer(profile).data

        return Response(data)

在前端，我使用了angular-file-upload lib。

這是我的文件輸入

<div ng-file-drop="" ng-file-select="" ng-model="organizer.photo" class="drop-box" drag-over-class="{accept:'dragover', reject:'dragover-err', delay:100}" ng-multiple="false" allow-dir="true" accept="image/*">
                                    Drop Images or PDFs<div>here</div>
</div>

這是我的上傳服務

main.js

(function () {
  'use strict';

  angular
    .module('trulii.utils.services')
    .factory('UploadFile', UploadFile);

  UploadFile.$inject = ['$cookies', '$http','$upload','$window','Authentication'];

  /**
  * @namespace Authentication
  * @returns {Factory}
  */
  function UploadFile($cookies, $http,$upload,$window,Authentication) {
    /**
    * @name UploadFile
    * @desc The Factory to be returned
    */


    var UploadFile = {
      upload_file: upload_file,
    };

    return UploadFile;


    function upload_file(file) {


      return $upload.upload({
        url: '/api/users/upload/photo/', // upload.php script, node.js route, or servlet url
        //method: 'POST' or 'PUT',
        //headers: {'Authorization': 'xxx'}, // only for html5
        //withCredentials: true,
        file: file, // single file or a list of files. list is only for html5
        //fileName: 'doc.jpg' or ['1.jpg', '2.jpg', ...] // to modify the name of the file(s)
        //fileFormDataName: myFile, // file formData name ('Content-Disposition'), server side request form name
                                    // could be a list of names for multiple files (html5). Default is 'file'
        //formDataAppender: function(formData, key, val){}  // customize how data is added to the formData. 
                                                            // See #40#issuecomment-28612000 for sample code

      })

    }


  }



})();