Can't set ImageField url attribute

问题

I want to change my ImageField's attribute, however I'm constantly getting the Can't set attribute error.

My model is

class Society(models.Model):
     name = models.CharField(max_length=200)
     slug = models.SlugField(unique=True)
     summary = models.TextField(blank=True,null=True)
     members = models.ManyToManyField(User,null=True,blank=True)
     gallery = models.ForeignKey(Gallery,null=True,blank=True)
     avatar = models.ImageField(upload_to=get_society_path)

     def save(self,*args,**kwargs):
          super(Society, self).save(*args,**kwargs)
          fix_avatar_path(self)

     def clean(self):
          if self.id:
               self.avatar.path = get_society_path(self,self.avatar.path)
               save_thumb(self.avatar.path)

And my helper functions are :

def get_society_path(instance,filename):
     seperator_val = instance.id
     if seperator_val is None:
          seperator_val = get_time()
     return '%s/society_%s/%s' % (settings.UPLOAD_ROOT,seperator_val,time_to_name(filename))

def fix_avatar_path(instance):
     org_society_path = get_society_path(instance,instance.avatar.name)
     make_upload_dir(org_society_path)
     move(instance.avatar.path,org_society_path)
     os.rmdir(os.path.dirname(instance.avatar.path))
     instance.clean()

The problem is :

I want to save my society directories as society_society_id. But normally, I can't assign any id before the model is saved. So i'm creating a tmp file whose name is a time value.Then to reach societies folder, I want to rename this file. So, my fix_avatar simply moves the tmp file's content to society_(society_id) folder after the society is saved. So far so good everything works well. However, my society's ImageField still holds the previously created folder. In order to change it's value, I found that i can use clean method.(from this SO question) But still i'm getting the same result, the path doesn't change, and gives the "can't set attribute" response.

Any idea ??

回答1:

Not sure, if this was ever changed in Django since this question was asked. A ticket about this not being possible still exists: https://code.djangoproject.com/ticket/15590

However, you actually can change the path by doing it like this:

self.avatar = 'uploads/example/path/'

What also does the job:

self.avatar.name = 'uploads/example/path/'

It has worked for us in several occasions.

回答2:

The problem is here:

self.avatar.path = get_society_path(self,self.avatar.path)

You cannot change the value of the path attribute in FileField/ImageField instances, it's readonly. There is a proposal to change this in Django 1.4

来源：https://stackoverflow.com/questions/5189114/cant-set-imagefield-url-attribute

标签

django

attributes

imagefield