django - 尝试将模型转换为 dict 时图像字段上的值错误
问题描述
我有 2 个模型,第一个是车库
class Garage(models.Model):
name = models.CharField(verbose_name=_('Garage'), max_length=200)
@property
def cars(self) -> list:
from django.forms.models import model_to_dict
cars = []
for i in Car.objects.filter(garage=self.id):
cars.append(model_to_dict(i))
return cars
def __str__(self):
return self.name
class Meta:
verbose_name = _('Garage')
我的第二个模型是汽车,
class Car(models.Model):
name = models.CharField(verbose_name=_('Car Name'), max_length=200)
garage = models.ForeignKey(verbose_name=_('Garage'), to=Garage, on_delete=models.PROTECT)
price = models.DecimalField(verbose_name=_('Price'), max_digits=10, decimal_places=2)
image = models.ImageField(verbose_name=_('Select Image'), upload_to='cars/', default=None)
def __str__(self):
return self.name
class Meta:
verbose_name = _("Car")
verbose_name_plural = _("Cars")
现在,当我尝试运行时,车库模型中的属性“汽车”会抛出 ValueError。
ValueError:“图像”属性没有与之关联的文件。
完整的错误日志是:
Traceback (most recent call last):
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner
response = get_response(request)
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/django/core/handlers/base.py", line 145, in _get_response
response = self.process_exception_by_middleware(e, request)
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/django/core/handlers/base.py", line 143, in _get_response
response = response.render()
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/django/template/response.py", line 106, in render
self.content = self.rendered_content
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/rest_framework/response.py", line 72, in rendered_content
ret = renderer.render(self.data, accepted_media_type, context)
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/rest_framework/renderers.py", line 107, in render
allow_nan=not self.strict, separators=separators
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/rest_framework/utils/json.py", line 28, in dumps
return json.dumps(*args, **kwargs)
File "/usr/lib/python3.7/json/__init__.py", line 238, in dumps
**kw).encode(obj)
File "/usr/lib/python3.7/json/encoder.py", line 199, in encode
chunks = self.iterencode(o, _one_shot=True)
File "/usr/lib/python3.7/json/encoder.py", line 257, in iterencode
return _iterencode(o, 0)
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/rest_framework/utils/encoders.py", line 67, in default
return tuple(item for item in obj)
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/rest_framework/utils/encoders.py", line 67, in <genexpr>
return tuple(item for item in obj)
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/django/core/files/base.py", line 78, in __iter__
for chunk in self.chunks():
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/django/core/files/base.py", line 55, in chunks
self.seek(0)
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/django/core/files/utils.py", line 20, in <lambda>
seek = property(lambda self: self.file.seek)
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/django/db/models/fields/files.py", line 41, in _get_file
self._require_file()
File "/home/PycharmProjects/venv/lib/python3.7/site-packages/django/db/models/fields/files.py", line 38, in _require_file
raise ValueError("The '%s' attribute has no file associated with it." % self.field.name)
ValueError: The 'image' attribute has no file associated with it.
我无法解决此错误,我需要对图像字段进行序列化。我该如何解决这个错误?
解决方案
所以,我能够解决我的问题。我刚刚创建了一个属性并为汽车模型生成了图像 url。
汽车模型.py
class Car(models.Model):
name = models.CharField(verbose_name=_('Car Name'), max_length=200)
garage = models.ForeignKey(verbose_name=_('Garage'), to=Garage, on_delete=models.PROTECT)
price = models.DecimalField(verbose_name=_('Price'), max_digits=10, decimal_places=2)
image = models.ImageField(verbose_name=_('Select Image'), upload_to='cars/', default=None)
@property
def image_url(self):
from django.contrib.sites.models import Site
domain = Site.objects.get_current().domain
url = 'http://{domain}'.format(domain=domain)
if self.image and hasattr(self.image, 'url'):
return url + self.image.url
def __str__(self):
return self.name
class Meta:
verbose_name = _("Car")
verbose_name_plural = _("Cars")
并且刚刚在 model_to_dict 字段过滤器中包含了这个 image_url 属性。
model_to_dict(i, fields=[..., 'image_url', ...]
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