python - 当我提交时，图像字段在 django 中被清除

Question

我正在尝试创建一个类似于 Instagram 的社交媒体应用程序，但是出于某种原因，当我将图片加载到图像字段并提交时，图像被清除，并说该字段是必需的。
Before submission
After submission
在 Django 中，代码为
View .py

@login_required
def new_post(request):
    if request.method == 'POST':
        form = CreateNewPost(request.POST)
        if form.is_valid():
            messages.success(request, "Post has been created")
            form.save()
            return redirect('home')
    else:
        form = CreateNewPost()
    return render (request, "posts/post_form.html", {"form":form})

我暂时将默认用户保留为无，因为它坚持让我在最初创建模型时选择一个。这是这个问题的原因吗？如果是这样，我该如何摆脱它。
html代码...

    <form method="POST" enctype="multipart/form-data">
        {% csrf_token %}
        <fieldset class="form-group">
            <legend class="border-bottom mb-4">Add a Post!</legend>
            {{ form | crispy }}
        </fieldset>
        <div class="form-group">
            <button class="btn btn-outline-info" type="submit">Post</button>                
        </div>
    </form>

模型.py

class Post(models.Model):
    image = models.ImageField(upload_to='post_images')
    caption = models.CharField(blank=True, max_length=254)
    date_posted = models.DateTimeField(auto_now_add=timezone.now)
    author = models.ForeignKey(User, on_delete = models.CASCADE)

    def save(self):
        super().save()
        img = Image.open(self.image.path)
        width, height = img.size
        ratio = width/height
        if img.height > 500:
            outputsize = (500, (height/ratio))
            img.thumbnail(outputsize)
            img.save(self.image.path)

表格.py

class CreateNewPost(forms.ModelForm):
    class Meta:
        model = Post
        fields = ["image","caption"]

以防万一，urls.py

urlpatterns = [
    path('', views.home, name='home'),
    path('new_post/', views.new_post, name="new_post"),
]

我也尝试过使用基于类的 View ，这给了我同样的错误

Answer 1

您需要通过 request.FILES [Django-doc]对于表单，这是一个类似字典的对象，其中包含 UploadedFile上传文件的对象:

@login_required
def new_post(request):
    if request.method == 'POST':
        form = CreateNewPost(request.POST, request.FILES)
        if form.is_valid():
            form.instance.author = request.user
            form.save()
            messages.success(request, 'Post has been created')
            return redirect('home')
    else:
        form = CreateNewPost()
    return render (request, 'posts/post_form.html', {'form':form})

Note: It is normally better to make use of the settings.AUTH_USER_MODEL [Django-doc] to refer to the user model, than to use the User model [Django-doc] directly. For more information you can see the referencing the User model section of the documentation.