CODEWITHSUNDEEP
pythondjangodjango-modelsdjango-forms
Riyad ELberkawy
Riyad ELberkawy

Reputation: 33

How to call the function in the class model when the field changes?

In this class when I add post I want to call category_change when the category field changes.

How can I do that?

class Post(models.Model):
    title = models.CharField(max_length=100)
    category = models.ForeignKey('Category', on_delete=models.CASCADE,null=True,blank=True,)
    image = models.ImageField(default='default.jpg', null=True, blank=True,editable=False)
    series = models.ForeignKey('Series', on_delete=models.CASCADE,null=True,blank=True,editable=False)
    tags = models.ManyToManyField('FilmTags', related_name='post')
    content = models.TextField()
    watch = models.TextField(null=True, default='')
    download_url = models.CharField(max_length=300, null=True, default="#")
    created = models.DateTimeField(default=timezone.now)
    updated = models.DateTimeField(auto_now=True)
    publish = models.BooleanField(default=True)
    views = models.IntegerField(default=0)

    def category_change(self):
        if category.title == "series":
            self.image.editable = True
            self.series.editable = True
            self.image = self.series.image
        else:
            self.image.editable = True

Upvotes: 2

Views: 728

Answers (3)

Ykh
Ykh

Reputation: 7717

Django signals is what you need. Signals will notify you instance changed, is something like database trigger. Demo is here:

signals.py:

from django.db.models.signals import post_save
from django.dispatch import receiver

from .model import Post


@receiver(post_save, sender=Post)
def is_category_changed(sender, instance=None, created=False, **kwargs):
    instance.category_change()

apps.py:

from django.apps import AppConfig


class PostConfig(AppConfig):
    name = 'Post'
    verbose_name = 'Post'

    def ready(self):
        import post.signals # post is your app name

Upvotes: 2

John
John

Reputation: 1

You need to build up the services you were into again so you can recovered you're in formation again

cmodels.TextField(null=True)

Upvotes: 0

Karam Mohamed
Karam Mohamed

Reputation: 881

You can add a method of creation , which takes the fields that you want to fill as arguments and create an instance , the method category_change() will be run withing this declaration

class Post(models.Model):
title = models.CharField(max_length=100)
category = models.ForeignKey('Category', 
           on_delete=models.CASCADE,null=True,blank=True,editable=False)
...
   def createPost(self,arg1,arg2,...) :
       post = self(title=arg1,category=arg2...)
       category_change()
       return post

# here is how you can call it
post = Post.createPost(title,category,...)

Upvotes: 0

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