Convert Django Model object to dict with all of the fields intact

There are many ways to convert an instance to a dictionary, with varying degrees of corner case handling and closeness to the desired result.

1. instance.__dict__

instance.__dict__

which returns

{'_foreign_key_cache': <OtherModel: OtherModel object>, '_state': <django.db.models.base.ModelState at 0x7ff0993f6908>, 'auto_now_add': datetime.datetime(2018, 12, 20, 21, 34, 29, 494827, tzinfo=<UTC>), 'foreign_key_id': 2, 'id': 1, 'normal_value': 1, 'readonly_value': 2}

This is by far the simplest, but is missing many_to_many, foreign_key is misnamed, and it has two unwanted extra things in it.

2. model_to_dict

from django.forms.models import model_to_dictmodel_to_dict(instance)

which returns

{'foreign_key': 2, 'id': 1, 'many_to_many': [<OtherModel: OtherModel object>], 'normal_value': 1}

This is the only one with many_to_many, but is missing the uneditable fields.

3. model_to_dict(..., fields=...)

from django.forms.models import model_to_dictmodel_to_dict(instance, fields=[field.name for field in instance._meta.fields])

which returns

{'foreign_key': 2, 'id': 1, 'normal_value': 1}

This is strictly worse than the standard model_to_dict invocation.

4. query_set.values()

SomeModel.objects.filter(id=instance.id).values()[0]

which returns

{'auto_now_add': datetime.datetime(2018, 12, 20, 21, 34, 29, 494827, tzinfo=<UTC>), 'foreign_key_id': 2, 'id': 1, 'normal_value': 1, 'readonly_value': 2}

This is the same output as instance.__dict__ but without the extra fields.foreign_key_id is still wrong and many_to_many is still missing.

5. Custom Function

The code for django's model_to_dict had most of the answer. It explicitly removed non-editable fields, so removing that check and getting the ids of foreign keys for many to many fields results in the following code which behaves as desired:

from itertools import chaindef to_dict(instance):    opts = instance._meta    data = {}    for f in chain(opts.concrete_fields, opts.private_fields):        data[f.name] = f.value_from_object(instance)    for f in opts.many_to_many:        data[f.name] = [i.id for i in f.value_from_object(instance)]    return data

While this is the most complicated option, calling to_dict(instance) gives us exactly the desired result:

{'auto_now_add': datetime.datetime(2018, 12, 20, 21, 34, 29, 494827, tzinfo=<UTC>), 'foreign_key': 2, 'id': 1, 'many_to_many': [2], 'normal_value': 1, 'readonly_value': 2}

6. Use Serializers

Django Rest Framework's ModelSerialzer allows you to build a serializer automatically from a model.

from rest_framework import serializersclass SomeModelSerializer(serializers.ModelSerializer):    class Meta:        model = SomeModel        fields = "__all__"SomeModelSerializer(instance).data

returns

{'auto_now_add': '2018-12-20T21:34:29.494827Z', 'foreign_key': 2, 'id': 1, 'many_to_many': [2], 'normal_value': 1, 'readonly_value': 2}

This is almost as good as the custom function, but auto_now_add is a string instead of a datetime object.

Bonus Round: better model printing

If you want a django model that has a better python command-line display, have your models child-class the following:

from django.db import modelsfrom itertools import chainclass PrintableModel(models.Model):    def __repr__(self):        return str(self.to_dict())    def to_dict(instance):        opts = instance._meta        data = {}        for f in chain(opts.concrete_fields, opts.private_fields):            data[f.name] = f.value_from_object(instance)        for f in opts.many_to_many:            data[f.name] = [i.id for i in f.value_from_object(instance)]        return data    class Meta:        abstract = True

So, for example, if we define our models as such:

class OtherModel(PrintableModel): passclass SomeModel(PrintableModel):    normal_value = models.IntegerField()    readonly_value = models.IntegerField(editable=False)    auto_now_add = models.DateTimeField(auto_now_add=True)    foreign_key = models.ForeignKey(OtherModel, related_name="ref1")    many_to_many = models.ManyToManyField(OtherModel, related_name="ref2")

Calling SomeModel.objects.first() now gives output like this:

{'auto_now_add': datetime.datetime(2018, 12, 20, 21, 34, 29, 494827, tzinfo=<UTC>), 'foreign_key': 2, 'id': 1, 'many_to_many': [2], 'normal_value': 1, 'readonly_value': 2}

I found a neat solution to get to result:

Suppose you have an model object o:

Just call:

type(o).objects.filter(pk=o.pk).values().first()

just vars(obj) , it will state the whole values of the object

>>> obj_attrs = vars(obj)>>> obj_attrs {'_file_data_cache': <FileData: Data>,  '_state': <django.db.models.base.ModelState at 0x7f5c6733bad0>,  'aggregator_id': 24,  'amount': 5.0,  'biller_id': 23,  'datetime': datetime.datetime(2018, 1, 31, 18, 43, 58, 933277, tzinfo=<UTC>),  'file_data_id': 797719, }

You can add this also

>>> keys = obj_attrs.keys()>>> temp = [obj_attrs.pop(key) if key.startswith('_') else None for key in keys]>>> del temp>>> obj_attrs   {    'aggregator_id': 24,    'amount': 5.0,    'biller_id': 23,    'datetime': datetime.datetime(2018, 1, 31, 18, 43, 58, 933277, tzinfo=<UTC>),    'file_data_id': 797719,   }