在django管理区域中抛出ValidationError之后，无法更改模型实例 [英] Cannot change model instance after a ValidationError is thrown in django admin area

问题描述

想象一下这样的模式：

class CFile(models.Model):
   filepath   = models.FileField(upload_to=...)
   collection = models.ForeignKey("FileCollection",null=True)
   ... # other attributes that are not relevant

   def clean(self):
     bname = os.path.basename
     if self.collection:
       cfiles = self.baseline.attachment_set.all()
       with_same_basename = filter(lambda e: bname(e.filepath.path) == bname(self.filepath.path),cfiles)
       if len(with_same_basename) > 0:
         raise ValidationError("There already exists a file with the same name in this collection")   

class FileCollection(models.Model):
  name = models.CharField(max_length=255)
  files= models.ManyToManyField("CFile")

如果已经存在具有相同基本名称的CFile，则禁止上传CFile，这就是为什么我添加了 clean 。问题是：

I want to disallow the upload of a CFile if there already exists a CFile with the same basename, that's why I added the clean. The problem is:

• 我上传了一个CFile，名称为 file1.png - >上传，因为没有其他具有此名称的文件存在


• 我上传另一个CFile，名称为 file1.png - > I得到我已经有这个名称的文件的预期错误。所以，我尝试更改文件，并上传不同名称的文件（ file2.png ）。问题是，我通过pdb在clean中停止，模型实例仍然是 file1.png 。我想象这是因为我的ValidationError和django允许我纠正我的错误。问题是，如果我无法上传另一个文件，我无法纠正。如何处理这个？

• I upload a CFile, with the name file1.png -> gets uploaded because no other files with this name exist
• I upload another CFile, with the name file1.png -> I get the expected error that I already have a file with this name. So, I try to change the file, and upload a file with a different name ( file2.png ). The problem is, I stopped via pdb in the clean, and the model instance is still file1.png. I imagine this happens because of my ValidationError and django allows me to "correct my mistake". The problem is I cannot correct it if I cannot upload another file. How can I handle this?

编辑：这在管理区域发生，不幸的是忘记提到这一点。我没有任何定制（除了 inlines = [FileInline] ）。

This happens in the admin area, sorry for forgetting to mention this before. I don't have anything custom ( besides inlines = [ FileInline ] ).

推荐答案

我认为最简单的方法是在你的模型中声明另一个字段的文件名，并使其对于每个集合都是唯一的。像这样：

I think the clearest way is to declare another field in your model for filename and make it unique for every collection. Like this:

class CFile(models.Model):
   filepath   = models.FileField(upload_to=...)
   collection = models.ForeignKey("FileCollection",null=True, related_name='files')
   filename = models.CharField(max_length=255)
   ... # other attributes that are not relevant

    class Meta:
        unique_together = (('filename', 'collection'),)

    def save(self, *args, **kwargs):
        self.filename = bname(self.filepath.path)
        super(CFile, self).save(args, kwargs)

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