Question

I have a simple article model with pub_date field and a unpublish_date field.

Is there any way to automagically set my is_published field to False when the unpublish_date is in the past?

class Article(models.Model):
    title = models.CharField(max_length=500)
    post = models.TextField(blank=True, null=True,)

    pub_date = models.DateTimeField(default=datetime.datetime.now)
    unpublish_date = models.DateTimeField(blank=True, null=True)
    is_published = models.BooleanField(default=True,)

Answer 1

You can simply factor this unpublish_date into your queries, for example:

articles_to_show = Articles.objects.filter(is_published=True,
                                        unpublish_date__gt=datetime.date.today())

This is likely to make your code more complicated, though. You’d have to rewrite all your queries to be aware of the unpublish_date.

Cron works for this sort of thing but is only good for changing things in large batches once or a few times a day. It doesn’t scale well when you have a large batch of tasks to do or want more fine-grained scheduling.

If running a task via cron once per day is sufficient, do that. It might be worth investigating more advanced options such as message queues, though.

To make a scheduled task which will run at a precise time (provided a worker is available), I would use Celery.

from celery.decorators import task

@task
def unpublish(article_pk):
    article = Article.objects.get(pk=article_pk)
    article.is_published = False
    article.save()

# Unpublish article in exactly 7 days from now
from datetime import datetime, timedelta
unpublish.apply_async([article.pk], eta=datetime.now() + datetime.timedelta(7))