我在 Django 模型中将字符串保存为文件时遇到问题,因为每当我尝试取回数据时,它都会给我一个 ValueError (“属性没有关联的文件”)。详细信息如下:
MODEL:
class GeojsonData(models.Model):
dname = models.CharField(max_length=200, unique=True)
gdata = models.FileField(upload_to='data')
def __str__(self):
return self.dname
保存数据的代码:
cf = ContentFile(stringToBeSaved)
gj = GeojsonDatua(dname = namevar, gdata = cf)
gj.save()
尝试读取数据的代码:
def readGeo(data):
f = GeojsonData.objects.all().get(id=data.id).gdata
f.open(mode ='rb')
geo = f.read()
return geo
追溯:
File "C:\Python\Python36-32\lib\site-packages\django\core\handlers\exception.py" in inner
41. response = get_response(request)
File "C:\Python\Python36-32\lib\site-packages\django\core\handlers\base.py" in _get_response
187. response = self.process_exception_by_middleware(e, request)
File "C:\Python\Python36-32\lib\site-packages\django\core\handlers\base.py" in _get_response
185. response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\Python\Python36-32\lib\site-packages\django\contrib\auth\decorators.py" in _wrapped_view
23. return view_func(request, *args, **kwargs)
File "C:\app\views.py" in mapa
80. geostr = app.readGeo.readGeo(d)
File "C:\app\readGeo.py" in readGeo
6. f.open(mode ='rb')
File "C:\Python\Python36-32\lib\site-packages\django\db\models\fields\files.py" in open
80. self._require_file()
File "C:Python\Python36-32\lib\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 /app/map/1
Exception Value: The 'gdata' attribute has no file associated with it.
您需要将 ContentFile 保存为实际文件。您应该调用字段的,而不是直接将其分配给字段save
方法并将其传入:
gj = GeojsonDatua(dname = namevar)
gj.gdata.save('myfilename', cf)
See the docs.
另请注意,如果您总是创建自己的gdata
像这样的字段,您可能根本不需要 FileField;或许可以使用 TextField 来代替。
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