从FileSystemStorage访问模型

Question

I have custom FileSystemStorage.
The idea is to pass optional filename parameter.
My custome storge code:

class SalesMapFileStores(FileSystemStorage):
    def __init__(self, location=None, base_url=None, filename=None):
        if filename:
            self.filename = filename
        super(SalesMapFileStores, self).__init__(location=location, base_url=base_url)

    def get_available_name(self, name):
        return name

    def get_valid_name(self, name):
        if self.filename:
            return self.filename
        return name

    def _save(self, name, content):
        if self.exists(name):
            self.delete(name)
        return super(SalesMapFileStores, self)._save(name, conten

What i whant is to pass this filename parameter from model.
Somethin like this:

class SalesMapImage(models.Model):
    name = models.CharField(max_length=254, verbose_name='Filename')
    image = SalesMapImageField(upload_to='SalesMap/Test', storage=SalesMapFileStores(filename=name), verbose_name='Test Image',
                               content_types=('image/jpeg', 'image/png'))

But in this case, Django passes as a parameter itself model.CharField (it's obvious :)).
The question is: how can I get access to my model instance from Storage?

Thanks in advance!

Answer 1

Well, it is a bit crazy idea but you can try to override the assignment to that field in that class so the SalesMapFileStores instance always keep in sync with the name field like this:

class SalesMapImage(models.Model):
    name = models.CharField(max_length=254, verbose_name='Filename')
    image = SalesMapImageField(upload_to='SalesMap/Test', storage=SalesMapFileStores(), verbose_name='Test Image',
                               content_types=('image/jpeg', 'image/png'))

    def __setattr__(self, key, value):
        self.__dict__[key]=value
        if key=='name':
            self.image.storage.filename = value

And the general idea is to hook the assignment of the value to the update of the filename field.

This is supposing that you don't want to update it manually from within your view. Because it wouldn't take much effort to do model_instance.storage.filename = self.name or even add a method to your custom storage class to update the filename.

UPDATE: Heads up for the storage=SalesMapFileStores() . There you are passing a instance of SalesMapFileStores . Not the class, so it might be possible you'll be using the same instace for storing all files and this my bring conflicts with filename . You can try it like this: storage=SalesMapFileStores

Hope this helps!