“用户”对象没有属性“ _committed”

Question

我正在制作一个简单的应用程序，用于对用户进行身份验证并允许他们上传文件。我有一个问题，当我尝试将用户作为外键添加到数据库的模型时，出现此错误：

'User' object has no attribute '_committed'

models.py

fs = FileSystemStorage(location='/media/uploads')

class FileInstance(models.Model):
    file = models.FileField(storage=fs)
    owner = models.ForeignKey(User, on_delete=models.SET_NULL, null=True)

views.py

def upload_file(request):
    if request.method == 'POST':
        file = FileInstance(request.FILES['file'], request.user)
        file.save()
    else:
        form = UploadFileForm()
    return render(request, 'upload.html')

upload.html

{% extends 'commons/base.html' %}
{% block title %} Dodaj plik {% endblock %}
{% block content %}
    <form method="post" enctype="multipart/form-data">
        {% csrf_token %}
        <input type="file" name="file">
        <button type="submit">Upload</button>
    </form>
{% endblock %}

堆栈跟踪：

Internal Server Error: /storage/upload/
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/dist-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/usr/local/lib/python3.6/dist-packages/django/core/handlers/base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/usr/local/lib/python3.6/dist-packages/django/core/handlers/base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/jch/PycharmProjects/2019Z_PAMIW_git_gr4/pamw2/storage/views.py", line 36, in upload_file
    file.save()
  File "/usr/local/lib/python3.6/dist-packages/django/db/models/base.py", line 741, in save
    force_update=force_update, update_fields=update_fields)
  File "/usr/local/lib/python3.6/dist-packages/django/db/models/base.py", line 779, in save_base
    force_update, using, update_fields,
  File "/usr/local/lib/python3.6/dist-packages/django/db/models/base.py", line 848, in _save_table
    for f in non_pks]
  File "/usr/local/lib/python3.6/dist-packages/django/db/models/base.py", line 848, in <listcomp>
    for f in non_pks]
  File "/usr/local/lib/python3.6/dist-packages/django/db/models/fields/files.py", line 286, in pre_save
    if file and not file._committed:
  File "/usr/local/lib/python3.6/dist-packages/django/utils/functional.py", line 257, in inner
    return func(self._wrapped, *args)
AttributeError: 'User' object has no attribute '_committed'

为什么会出现此错误，如何解决呢？我的数据模型是否正确，如果不正确，该如何更改？

修改后

models.py

class FileInstanceForm(ModelForm):
    class Meta:
        model = FileInstance
        fields = ['file']

views.py

def upload_file(request):
    if request.method == 'POST':
        form = FileInstanceForm(request.POST, request.FILES)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect('files.html')
    else:
        form = FileInstanceForm()
    return render(request, 'upload.html', {form: form})

upload.html

<form action="." method="post" enctype="multipart/form-data">
        {% csrf_token %}
        {{ form.as_p }}
        <input type="submit" value="Upload"/>

我的表格显示不正确。我没有办法附加文件，并且html无法渲染。就是这样：