Question

I am trying to create a system that enables the admin to upload a zipfile, then the script will automatically, using signals, unzip it, search for all the files in jpg,png. create a list of them and generate a database record according to it.

In models, i have Project and Photo table, Photo has Many-to-One aka Foreign Key relationship with Project.

The script below is with the signal i am working. I can get instance.file_zip.path without errors, and the script works well when run manually.

Long-time debugging and I assume that there is something wrong with belongs_to=instance but I do not know how to fix it as I didn’t actually understand why it gaves an error.
The extraction part works fine, I just put them here for reference, most likely you will not need to read and understand it.

@receiver(post_save, sender=Project)
def unzip_and_process(sender, instance, **kwargs):
    #project_zip = FieldFile.open(file_zip, mode='rb')
    file_path = instance.file_zip.path
    file_list = []
    with zipfile.ZipFile(file_path, 'r') as project_zip:
        project_zip.extractall(re.search('[^\s]+(?=\.zip)', file_path).group(0))
        project_zip.close()
    for root, dirs, files in os.walk(file_path):
        for filename in files:
            file_list.append(os.path.join(root, filename))
    photo_list = filter(filter_photos, file_list)
    for photo in photo_list:
        print 'Processing %s'%photo
        p = Photo.objects.create(belongs_to=instance, img=photo, desc='Processed from zipfile')
        p.save()

update

class Project(models.Model):
    project_name=models.CharField(max_length=150)
    date_taken=models.DateField()
    date_deadline=models.DateField()
    price=models.FloatField()
    price_paid=models.BooleanField()
    owner=models.ForeignKey(User)
    file_zip=models.FileField(upload_to='projects/%Y/%m/%d')

    def __unicode__(self):
        return self.project_name

    def file_path(self):
        return re.search('[^\s]+(?=\.zip)', self.file_zip.name).group(0)

class Photo(models.Model):

    def project_path(instance, filename):
        return '%s/%s'%(instance.belongs_to.file_path(),filename)

    belongs_to=models.ForeignKey(Project, verbose_name="related_project")
    img=models.ImageField(upload_to=project_path, max_length=255)
    desc=models.CharField(max_length=255)

    def __unicode__(self):
        return '%s FROM [%s]'%(self.img.name,self.belongs_to)

Answer 1

for root, dirs, files in os.walk(file_path):

file_path refers to a zip file. not a directory hence os.walk returns nothing