python – Django. Override save for model

python – Django. Override save for model

Some thoughts:

class Model(model.Model):
    _image=models.ImageField(upload_to=folder)
    thumb=models.ImageField(upload_to=folder)
    description=models.CharField()

    def set_image(self, val):
        self._image = val
        self._image_changed = True

        # Or put whole logic in here
        small = rescale_image(self.image,width=100,height=100)
        self.image_small=SimpleUploadedFile(name,small_pic)

    def get_image(self):
        return self._image

    image = property(get_image, set_image)

    # this is not needed if small_image is created at set_image
    def save(self, *args, **kwargs):
        if getattr(self, _image_changed, True):
            small=rescale_image(self.image,width=100,height=100)
            self.image_small=SimpleUploadedFile(name,small_pic)
        super(Model, self).save(*args, **kwargs)

Not sure if it would play nice with all pseudo-auto django tools (Example: ModelForm, contrib.admin etc).

Check the models pk field. If it is None, then it is a new object.

class Model(model.Model):
    image=models.ImageField(upload_to=folder)
    thumb=models.ImageField(upload_to=folder)
    description=models.CharField()


    def save(self, *args, **kwargs):
        if form in kwargs:
            form=kwargs[form]
        else:
            form=None

        if self.pk is None and form is not None and image in form.changed_data:
            small=rescale_image(self.image,width=100,height=100)
            self.image_small=SimpleUploadedFile(name,small_pic)
        super(Model, self).save(*args, **kwargs)

Edit: Ive added a check for image in form.changed_data. This assumes that youre using the admin site to update your images. Youll also have to override the default save_model method as indicated below.

class ModelAdmin(admin.ModelAdmin):
    def save_model(self, request, obj, form, change):
        obj.save(form=form)

python – Django. Override save for model

You may supply extra argument for confirming a new image is posted.
Something like:

def save(self, new_image=False, *args, **kwargs):
    if new_image:
        small=rescale_image(self.image,width=100,height=100)
        self.image_small=SimpleUploadedFile(name,small_pic)
    super(Model, self).save(*args, **kwargs)

or pass request variable

def save(self, request=False, *args, **kwargs):
    if request and request.FILES.get(image,False):
        small=rescale_image(self.image,width=100,height=100)
        self.image_small=SimpleUploadedFile(name,small_pic)
    super(Model, self).save(*args, **kwargs)

I think these wont break your save when called simply.

You may put this in your admin.py so that this work with admin site too (for second of above solutions):

class ModelAdmin(admin.ModelAdmin):

    ....
    def save_model(self, request, obj, form, change): 
        instance = form.save(commit=False)
        instance.save(request=request)
        return instance

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