Overriding get() method in models

Question

Am trying to override get() method in my view as :

broadcast = Broadcast.objects.get(request, pk = broadcast_id)

In my model am overriding method as :

class Broadcast(models.Model):      
    person = models.ForeignKey(User)
    post = models.CharField(max_length=300 , verbose_name = 'Say it out loud !')
    .
    .

    def get(self, *args, **kwargs):
        if request.user == self.person :
            super(Broadcast, self).get(*args, **kwargs)
        else :
            return none

Two questions ->
Where am I going wrong with the overriding?
How do I access the "request" argument passed into get?

score 22 · Answer 1 · answered Dec 14 '16 at 16:22

Given the poll app example in the Django tutorial. You can perform a get operation to fetch poll questions from the database.

In : Question.objects.get(pk=1)
Out: <Question: Question object>

This blog post shows how to override that method. It is not on the model itself. Question.objects gives you the manager.

In : Question.objects
Out: <django.db.models.manager.Manager at 0x10d3b8860>

You can drop in a custom manager in your models.py.

class QuestionManager(models.Manager):
    pass

class Question(models.Model):
    objects = QuestionManager()

which results in...

In : Question.objects
Out: <app.models.QuestionManager at 0x107456e48>

But we are not quite there yet. Question.objects.get is doing some delegation magic and actually calling get on an instance of QuerySet. We can replace

class QuestionQuerySet(models.query.QuerySet):
    def get(self, **kwargs):
        print('hello world')
        return super().get(**kwargs)

class QuestionManager(models.Manager.from_queryset(QuestionQuerySet)):
    pass

Voilà!

In : Question.objects.get(pk=1)
hello world
Out: <Question: Question object>

References:

score 10 · Accepted Answer · edited Apr 17 '15 at 14:35

10

get isn't a method on the model - you access it via objects, so it's a method on the Manager. See the official Manager documentation.

The way you have defined the method signature, the request is available as args[0].

edited Apr 17 '15 at 14:35

djds23

91
1
7

answered Jun 29 '11 at 12:29

Daniel Roseman

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So how do I override the Manager's method get ? – D_D Jun 29 '11 at 12:48
1

Er, by defining a custom Manager subclass with an overridden get method, as shown in that documentation... – Daniel Roseman Jun 29 '11 at 12:52
6

Unfortunately, the documentation you refer to does not have an explicit example of an overridden `get` method. – physicalattraction Dec 12 '16 at 09:49

score 1 · Answer 3 · answered Feb 19 '19 at 13:28

1

Note that more modern Django versions (since 1.7), provide an easier way to do this. Check out the as_manager() QuerySet method.

https://docs.djangoproject.com/en/2.2/topics/db/managers/#creating-a-manager-with-queryset-methods

answered Feb 19 '19 at 13:28

Owen

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Overriding get() method in models

3 Answers3

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