尝试在 Django 中删除图像或创建新用户时 ImageField 上的 ValueError

Question

我已经在我的 Django 模型上放置了一个 ImageField，并且它可以使用预先存在的配置文件（图像上传），但是我无法从管理面板中删除图像，也无法创建新用户。
抛出的错误是：

/admin/custom_user/customuser/1/ 处的值错误
'avatar' 属性没有与之关联的文件。
请求方式：POST
请求地址： http://localhost:8000/admin/custom_user/customuser/1/
Django 版本：1.8
异常类型：值错误
异常值：“头像”属性没有与之关联的文件。
异常位置：/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/db/models/fields/files.py in _require_file, line 46
Python 可执行文件：/home/stefano/projects/blog-project/blogprojectenv/bin/python
Python 版本：2.7.6
蟒蛇路径：
['/home/stefano/projects/blog-project',
'/home/stefano/projects/blog-project/blogprojectenv/lib/python2.7',
'/home/stefano/projects/blog-project/blogprojectenv/lib/python2.7/plat-x86_64-linux-gnu',
'/home/stefano/projects/blog-project/blogprojectenv/lib/python2.7/lib-tk',
'/home/stefano/projects/blog-project/blogprojectenv/lib/python2.7/lib-old',
'/home/stefano/projects/blog-project/blogprojectenv/lib/python2.7/lib-dynload',
'/usr/lib/python2.7',
'/usr/lib/python2.7/plat-x86_64-linux-gnu',
'/usr/lib/python2.7/lib-tk',
'/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages'] 服务器时间：2016 年 3 月 24 日星期四 13:12:38 +0000

这是模型

class CustomUser(AbstractBaseUser, PermissionsMixin):
    first_name   = models.CharField(max_length=254, blank=True)
    second_name  = models.CharField(max_length=254, blank=True)
    email        = models.EmailField(blank=True, unique=True)
    date_joined  = models.DateTimeField(_('date joined'), default=datetime.now())
    avatar       = models.ImageField('profile picture', upload_to='images/avatars/', null=True, blank=True)
    is_active    = models.BooleanField(default=True)
    is_admin     = models.BooleanField(default=False)
    is_staff     = models.BooleanField(default=False)

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = ['first_name', 'second_name']

    objects = CustomUserManager()

    class Meta:
        verbose_name = _('user')
        verbose_name_plural = _('users')

    def save(self, *args, **kwargs):
        pil_image_obj = Image.open(self.avatar)
        new_image = resizeimage.resize_width(pil_image_obj, 300)

        new_image_io = BytesIO()
        new_image.save(new_image_io, format='JPEG')

        temp_name = self.avatar.name
        self.avatar.delete(save=False)

        self.avatar.save(
            temp_name,
            content=ContentFile(new_image_io.getvalue()),
            save=False
        )

        super(CustomUser, self).save(*args, **kwargs)

我试图在模型上放置 null=True 和 blank=True ，但错误仍然存​​在。 我试图将 required=False 放在 forms.py 中的“ init ”方法上

class CustomUserChangeForm(forms.ModelForm):
    email = forms.EmailField(label='', required=True, widget = forms.TextInput(
        attrs = {
            'placeholder': 'E-Mail',
            'class': 'form-control'
        }
    ))

    first_name = forms.CharField(label='', required=True, widget=forms.TextInput(
        attrs = {
            'placeholder': 'First name',
            'class': 'form-control'
        }
    ))

    second_name = forms.CharField(label='', required=True, widget=forms.TextInput(
        attrs = {
            'placeholder': 'Second name',
            'class': 'form-control'
        }
    ))

    avatar = forms.ImageField(label='', required=False, widget=forms.FileInput(
        attrs = {
            'class': 'form-control',
            'label': 'Profile pic'
        }
    ))

    class Meta:
        model = CustomUser
        fields = ('email', 'first_name', 'second_name', 'avatar')

    def __init__(self, *args, **kwargs):
        self.user = kwargs.pop('user', None)
        super(CustomUserChangeForm, self).__init__(*args, **kwargs)
        self.fields['avatar'].required = False

    def clean_email_address(self):
        email = self.cleaned_data.get('email')
        if self.user and self.user.email == email:
            return email
        if CustomUser.objects.filter(email=email).count():
            raise forms.ValidationError(u'That email address already exists.')
        return email

    def save(self, commit=True):
        user = super(CustomUserChangeForm, self).save(commit=False)
        user.email = self.cleaned_data['email']

        if commit:
            user.save()

        return user

还在那儿。

可以做什么？

编辑：这是完整的追溯

Environment:


Request Method: POST
Request URL: http://localhost:8000/admin/custom_user/customuser/1/

Django Version: 1.8
Python Version: 2.7.6
Installed Applications:
('django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'blog',
 'custom_user',
 'django_markdown',
 'parsley')
Installed Middleware:
('django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware',
 'django.middleware.security.SecurityMiddleware')


Traceback:
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  132.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/contrib/admin/options.py" in wrapper
  616.                 return self.admin_site.admin_view(view)(*args, **kwargs)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  110.                     response = view_func(request, *args, **kwargs)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func
  57.         response = view_func(request, *args, **kwargs)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/contrib/admin/sites.py" in inner
  233.             return view(request, *args, **kwargs)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/contrib/admin/options.py" in change_view
  1519.         return self.changeform_view(request, object_id, form_url, extra_context)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapper
  34.             return bound_func(*args, **kwargs)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  110.                     response = view_func(request, *args, **kwargs)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/utils/decorators.py" in bound_func
  30.                 return func.__get__(self, type(self))(*args2, **kwargs2)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/utils/decorators.py" in inner
  145.                     return func(*args, **kwargs)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/contrib/admin/options.py" in changeform_view
  1467.                 self.save_model(request, new_object, form, not add)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/contrib/admin/options.py" in save_model
  1078.         obj.save()
File "/home/stefano/projects/blog-project/custom_user/models.py" in save
  66.       pil_image_obj = Image.open(self.avatar)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/PIL/Image.py" in open
  2261.         fp.seek(0)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/core/files/utils.py" in <lambda>
  20.     seek = property(lambda self: self.file.seek)
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/db/models/fields/files.py" in _get_file
  49.         self._require_file()
File "/home/stefano/projects/blog-project/blogprojectenv/local/lib/python2.7/site-packages/django/db/models/fields/files.py" in _require_file
  46.             raise ValueError("The '%s' attribute has no file associated with it." % self.field.name)

Exception Type: ValueError at /admin/custom_user/customuser/1/
Exception Value: The 'avatar' attribute has no file associated with it.

Answer 1

我认为在打开头像图像之前询问self.avatar是否self.avatar ，因为从我的角度来看，如果没有头像，则没有理由删除它。 像这样的东西：

def save(self, *args, **kwargs):
    if self.avatar:
        pil_image_obj = Image.open(self.avatar)
        new_image = resizeimage.resize_width(pil_image_obj, 300)

        new_image_io = BytesIO()
        new_image.save(new_image_io, format='JPEG')

        temp_name = self.avatar.name
        self.avatar.delete(save=False)

        self.avatar.save(
            temp_name,
            content=ContentFile(new_image_io.getvalue()),
            save=False
        )

    super(CustomUser, self).save(*args, **kwargs)

我希望这可以帮助您找到解决方案。 谢谢 ：）

Answer 2

创建实例时，磁盘上没有存储头像文件。 所以你尝试打开不存在的文件。

我看到你想在更新后删除旧文件？

所以你不需要覆盖save方法。 您应该做的是使用pre_save 、 post_save和post_delete方法。

在pre_save你存储当前的头像，在post_save更新后你应该用旧的检查新实例的文件路径。 如果不同，则通过os.remove删除它

在post_delete只删除文件。

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