Django classes to make your models, managers, and querysets serializable, with built-in support for related objects in ~100 LoC (shorter than this README!)
I. Installation
II. Usage
III. How it Works
IV. Related Libraries
V. Backstory
pip install django-serializable-modelIt is expected that you already have Django installed
Tested on Django 2.2, 1.11, 1.9, and 1.5 as well as Python 3.5, 3.4, and 2.7
- Should work with Django 1.4-2.x and Python 2.7-3.x
- Has several Django backward & forward compatibility fixes built-in
- Likely works with Django 0.95-1.3 as well
- Pre 1.3 does not support the
on_deleteargument on relations. This only affects the usage and examples below; the internals are unaffected. - Pre 0.95, the Manager API didn't exist, so some functionality may be limited in those versions, or it may just error on import
- Pre 1.3 does not support the
- Have not confirmed if this works with earlier versions of Python.
Please submit a PR or file an issue if you have a compatibility problem or have confirmed compatibility on versions.
Simplest use case, just implements the .serialize() function on a model:
from django.db import models
from django_serializable_model import SerializableModel
class User(SerializableModel):
email = models.CharField(max_length=765, blank=True)
name = models.CharField(max_length=100)
new_user = User.objects.create(
name='John Doe',
email='john@doe.com',
)
print new_user.serialize()
# {'id': 1, 'email': 'john@doe.com', 'name': 'John Doe'}With an override of the default .serialize() function to only include whitelisted fields in the serialized dictionary:
from django.db import models
from django_serializable_model import SerializableModel
class User(SerializableModel):
email = models.CharField(max_length=765, blank=True)
name = models.CharField(max_length=100)
# whitelisted fields that are allowed to be seen
WHITELISTED_FIELDS = set([
'name',
])
def serialize(self, *args, **kwargs):
"""Override serialize method to only serialize whitelisted fields"""
fields = kwargs.pop('fields', self.WHITELISTED_FIELDS)
return super(User, self).serialize(*args, fields=fields)
new_user = User.objects.create(
name='John Doe',
email='john@doe.com',
)
print new_user.serialize()
# {'name': 'John Doe'}With a simple, one-to-one relation:
from django.db import models
from django_serializable_model import SerializableModel
class User(SerializableModel):
email = models.CharField(max_length=765, blank=True)
name = models.CharField(max_length=100)
class Settings(SerializableModel):
user = models.OneToOneField(User, primary_key=True,
on_delete=models.CASCADE)
email_notifications = models.BooleanField(default=False)
def serialize(self, *args):
"""Override serialize method to not serialize the user field"""
return super(Settings, self).serialize(*args, exclude=['user'])
new_user = User.objects.create(
name='John Doe',
email='john@doe.com',
)
Settings.objects.create(user=new_user)
new_user_refreshed = User.objects.select_related('settings').get(pk=new_user.pk)
print new_user_refreshed.serialize()
# {'id': 1, 'email': 'john@doe.com', 'name': 'John Doe'}
# recursively serialize Settings object by passing the join in
print new_user_refreshed.serialize('settings')
# {'id': 1, 'email': 'john@doe.com', 'settings': {'email_notifications': False}, 'name': 'John Doe'}With a foreign key relation:
from django.db import models
from django_serializable_model import SerializableModel
class User(SerializableModel):
email = models.CharField(max_length=765, blank=True)
name = models.CharField(max_length=100)
class Post(SerializableModel):
user = models.ForeignKey(User, on_delete=models.CASCADE)
text = models.TextField()
new_user = User.objects.create(
name='John Doe',
email='john@doe.com',
)
Post.objects.create(user=new_user, text='wat a nice post')
Post.objects.create(user=new_user, text='another nice post')
# called on QuerySet
print Post.objects.all().serialize()
# [{'id': 1, 'text': 'wat a nice post', 'user_id': 1}, {'id': 2, 'text': 'another nice post', 'user_id': 1}]
# adds an _id to the foreign key name, just like when using `.values()`
# called on Manager
user1 = User.objects.get(pk=new_user.pk)
print user1.post_set.serialize()
# [{'id': 1, 'text': 'wat a nice post', 'user_id': 1}, {'id': 2, 'text': 'another nice post', 'user_id': 1}]
# recursively serialize Post objects by passing the join in
print User.objects.prefetch_related('post_set').get(pk=new_user.pk).serialize('post_set')
"""
{
'id': 1,
'email': 'john@doe.com',
'name': 'John Doe',
'post_set': [{'id': 1, 'text': 'wat a nice post', 'user_id': 1}, {'id': 2, 'text': 'another nice post', 'user_id': 1}]
}
""".serialize takes in any number of joins as its *args and they can be of any depth, using the same __ syntax as prefetch_related. This means if your Post object also had Comment objects, you could write:
User.objects.prefetch_related('post_set__comment_set').serialize('post_set__comment_set')and get an array of Comment dictionaries within each Post dictionary. If your Post object also had Like objects:
joins = ['post_set__comment_set', 'post_set__like_set']
User.objects.prefetch_related(*joins).serialize(*joins)Since .serialize outputs a dictionary, one can turn it into JSON simply by using json.dumps on the dictionary.
If you're building an API, you can use JSONResponse on the dictionary as well.
Implementing a .serialize method on Models, Managers, and QuerySets allows for easily customizable whitelists and blacklists (among other things) on a per Model basis.
This type of behavior was not possible a simple recursive version of model_to_dict, but is often necessary for various security measures and overrides.
In order to recurse over relations / joins, it accepts the same arguments as the familiar prefetch_related, which, in my use cases, often immediately precedes the .serialize calls.
.serialize also uses a custom model_to_dict function that behaves a bit differently than the built-in one in a variety of ways that are more expected when building an API (see the docstring).
I'd encourage you to read the source code, since it's shorter than this README :)
- django-api-decorators
Tiny decorator functions to make it easier to build an API using Django in ~100 LoC
This library was built while I was working on Yorango's ad-hoc API. Writing code to serialize various models was complex and quite tedious, resulting in messy spaghetti code for many of our API methods. The only solutions I could find online were the Django Full Serializers from wadofstuff as well as some recursive model_to_dict snippets online -- none of which gave the option for customizable whitelists and blacklists on a per Model basis.
Later on, I found that Django REST Framework's ModelSerializers do offer similar functionality to what I was looking for (and without requiring buy-in to the rest of the framework), albeit with some added complexity and robustness.
I ended up writing my own solution in ~100 LoC that handled basically all of my needs and replaced a ton of messy serialiazation code from all around the codebase. It was used in production with fantastic results, including on queries with quite the complexity and depth, such as:
joins = ['unit_set', 'unit_set__listing_set',
'unit_set__listing_set__tenants', 'unit_set__listing_set__bill_set',
'unit_set__listing_set__payment_set__payer',
'unit_set__listing_set__contract']
s_props = (user.property_set.all().prefetch_related(*joins)
.serialize(*joins))Had been meaning to extract and open source this as well as other various useful utility libraries I had made at Yorango and finally got the chance!