ajax - angularjs http post image file to drf rest interface got error: AttributeError: 'OrderedDict' object has no attribute 'pk' -

i creating system consisting angularjs frontend web app , drf rest interface. can use command line 'curl' upload image file drf rest interface, when use angularjs http post, got error message: 'ordereddict' object has no attribute 'pk'

my drf setup follows:

models.py: def upload_to(instance, filename):     return 'post_image/{0}/{1}'.format(instance.author.id, filename)  class postimage(models.model):     author = models.foreignkey(author, blank=false, editable=false, related_name='images')     post = models.foreignkey(post, blank=false, editable=false, related_name='images')      image = models.imagefield(_('image'), blank=true, null=true, upload_to=upload_to)     created = models.datetimefield(editable=false)     updated = models.datetimefield(editable=false)      def __unicode__(self):         return self.name      def save(self, *args, **kwargs):         ''' on save, update timestamps '''         if not self.id:             self.created = timezone.now()         self.updated = timezone.now()         return super(postimage, self).save(*args, **kwargs)   serializers.py class postimageserializer(serializers.hyperlinkedmodelserializer):     author = serializers.hyperlinkedrelatedfield(read_only=true, view_name='author-detail')     post = serializers.hyperlinkedrelatedfield(read_only=true, view_name='post-detail')      class meta:         model = postimage         fields = ('url', 'image', 'author', 'post', 'created', 'updated')  views.py class postimageview(generics.listcreateapiview):     """     list , create post image endpoint     allowed request method: get, post     """     serializer_class = postimageserializer     permission_classes = [permissions.isauthenticated]     parser_classes = (formparser, multipartparser, fileuploadparser,)      def get_queryset(self):         queryset = super(postimageview, self).get_queryset()         return queryset.filter(post__pk=self.kwargs['pk'])      def perform_create(self, serializer):         post = post.objects.get(pk=self.kwargs['pk'])         if 'upload' in self.request.data:             file_obj = self.request.data['upload']             serializer.save(author=self.request.user, post=post, image=file_obj)             return response(status=status.http_201_created)         else:             return response(status=status.http_400_bad_request)   using jwt authentication: rest_framework = {     'default_authentication_classes': (         'rest_framework_jwt.authentication.jsonwebtokenauthentication',     ) , } 

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log error message:

internal server error: /api/v1/post/22/image traceback (most recent call last):   file "/root/rest_drf/env/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 132, in get_response     response = wrapped_callback(request, *callback_args, **callback_kwargs)   file "/root/rest_drf/env/local/lib/python2.7/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view     return view_func(*args, **kwargs)   file "/root/rest_drf/env/local/lib/python2.7/site-packages/django/views/generic/base.py", line 71, in view     return self.dispatch(request, *args, **kwargs)   file "/root/rest_drf/env/local/lib/python2.7/site-packages/rest_framework/views.py", line 452, in dispatch     response = self.handle_exception(exc)   file "/root/rest_drf/env/local/lib/python2.7/site-packages/rest_framework/views.py", line 449, in dispatch     response = handler(request, *args, **kwargs)   file "/root/rest_drf/env/local/lib/python2.7/site-packages/rest_framework/generics.py", line 244, in post     return self.create(request, *args, **kwargs)   file "/root/rest_drf/env/local/lib/python2.7/site-packages/rest_framework/mixins.py", line 21, in create     headers = self.get_success_headers(serializer.data)   file "/root/rest_drf/env/local/lib/python2.7/site-packages/rest_framework/serializers.py", line 466, in data     ret = super(serializer, self).data   file "/root/rest_drf/env/local/lib/python2.7/site-packages/rest_framework/serializers.py", line 215, in data     self._data = self.to_representation(self.validated_data)   file "/root/rest_drf/env/local/lib/python2.7/site-packages/rest_framework/serializers.py", line 435, in to_representation     ret[field.field_name] = field.to_representation(attribute)   file "/root/rest_drf/env/local/lib/python2.7/site-packages/rest_framework/relations.py", line 264, in to_representation     return self.get_url(value, self.view_name, request, format)   file "/root/rest_drf/env/local/lib/python2.7/site-packages/rest_framework/relations.py", line 199, in get_url     if obj.pk none: attributeerror: 'ordereddict' object has no attribute 'pk' [pid: 29484|app: 0|req: 2/4] 76.114.185.25 () {54 vars in 1242 bytes} [sun jan 24 16:41:13 2016] post /api/v1/post/22/image => generated 107983 bytes in 153 msecs (http/1.1 500) 2 headers in 92 bytes (1 switches on core 1)