Allow non-field attributes to be serialized

[valankar@…]

It seems if I create a request set with extra(), the fields are not in the output generated by serialize().

[wnielson]

I added a quick patch to allow extra attributes to be serialized. Here's an example:

serialize(Blog.objects.all(), fields=('title',), attrs=('entry_count',))

where 'entry_count' is an attribute (not a Django field) of Blog.

[wnielson]

I added another patch which I think is better because it works directly with extra. If a QuerySet passed to serialize contains something in _select and the kwargs extra=True is passed, then those fields will be included in the output. Example:

serialize(Entry.objects.extra(select={'is_recent': "pub_date > '2006-01-01'"}), extra=True)

[Jacob]

In general the serializer framework needs ways of adding arbitrary extra fields onto serialized data. This patch is a bit too specialized, but I'm leaving it open so we can keep an eye on this use case.

[Oroku Saki]

(Moved example from duplicate ticket# 12862 to here)

Let's say I have this class:

class Cart(models.Model):
    account = models.ForeignKey(Account)
    
    @property
    def total(self):
        total = 0
        for item in self.item_set:
            total += item.price
        return total

Obviously if I were to serialize this model, I would want the total to be serialized. I wouldn't mind having to include it in fields=() argument of serialize().

[Aymeric Augustin]

Change UI/UX from NULL to False.

[senko]

Here's a pull request adding an extra keyword argument to serialize() method that allows the user to specify non-field attributes on the model that they wish to serialize. Also added a note in the docs that deserialization of models serialized with extra won't work as deserializer wants all the fields to actually be model fields.

PR: ​https://github.com/django/django/pull/1176

[Tim Graham]

Patch no longer merges cleanly.

[Dan F]

Not sure if we still want this, but I filed an updated PR at ​https://github.com/django/django/pull/16004, just to try out contributing.

[Dan F]

I would prefer to close this over submitting code, unless someone who is still around is actually requesting this feature.

[Dan F]

Given what I see (last changes were 13 years ago), I am closing this.

I'm fine if someone wants to re-open it who actually wants the feature. Then we can talk about what they want, to help with the discussion on ​https://github.com/django/django/pull/16004.