Django Value Error "seek of closed file" using PIL for image resize when updating a record

Question

I have the following model:

class Players(models.Model):
    team = models.ForeignKey(Teams, verbose_name=_('Team'), on_delete=models.CASCADE)
    player_name = models.CharField(_('Player Name'),max_length=200)
    player_description = models.TextField(_('Player Description'))
    player_image = models.ImageField(_('Profile Pic'),upload_to='upload/player_image', null=True, blank=True)
    player_social = models.CharField(_('Social Media Tag'),max_length=200)

    class Meta:
        verbose_name = _("Players")
        verbose_name_plural = _("Players")

    def __str__(self):
        return self.team.team_name + ' - ' + self.player_name
    
    def save(self, *args, **kwargs):
        super().save(*args, **kwargs)
        if self.player_image:
            image_resize(self.player_image, 250)

The last function will call another for image resizing taking the file and an expected max width:

# Use PIL to resize images; set target width on each
def image_resize(image, tgt_width):
        img = PIL.Image.open(image)
        img.load()
        width, height = img.size
        target_width = tgt_width
        h_coefficient = width/tgt_width
        target_height = height/h_coefficient
        img = img.resize((int(target_width), int(target_height)), PIL.Image.ANTIALIAS)
        img.save(image.path, quality=100)
        img.close()
        image.close()

My view for updating is as follows:

@method_decorator(superuser_required, name='dispatch')
class PlayerUpdateView(UpdateView):
    model = Players
    template_name = 'scoreboard/players/player_update.html'
    form_class = PlayersForm
    context_object_name: str = 'player'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        team_id = Players.objects.get(pk=self.kwargs['pk']).team.id
        context["team"] = Teams.objects.get(pk=team_id)
        return context
    
    def form_valid(self, form):
        form.save()
        return super().form_valid(form)

    def get_success_url(self):
        team_id = Players.objects.get(pk=self.kwargs['pk']).team.id
        return reverse_lazy('team_detail', kwargs={'pk': team_id})

It doesn’t matter if I provide a new image file or not, I get the same "seek of closed file" error:

  File "D:0_wwwhts-scoreoverlayscoreboardmodels.py", line 62, in save
    image_resize(self.player_image, 250)
  File "D:0_wwwhts-scoreoverlayscoreboardmodels.py", line 15, in image_resize
    img = PIL.Image.open(image)
  File "D:0_wwwhts-scorevenvlibsite-packagesPILImage.py", line 3096, in open
    fp.seek(0)
ValueError: seek of closed file

How can I get the image to be processed anyway? What am I missing?

I tried adding the if method so in case there is no file, it won’t trigger the resize function. I was expecting the function to check for the presence of an image file, then process it. Adding img.load() doesn’t help.

Asked By: Victor Donoso

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Source

Answer 1

So, after a few tries I found this answer. I’m not very sure why it works, but it seems like the with method opens and closes the file correctly. Found this on PIL Documentation. The image_resize() function will look like this:

def image_resize(image, tgt_width):
    with Image.open(image) as img:
        width, height = img.size
        ratio = width / height
        tgt_height = int(tgt_width / ratio)
        img = img.resize((tgt_width, tgt_height), Image.ANTIALIAS)
        img.save(image.path)

With the if condition at the save method, it works every time.

Answered By: Victor Donoso

Django Value Error "seek of closed file" using PIL for image resize when updating a record

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