django-rest-framework-tricks

Collection of various tricks for Django REST framework.

Prerequisites

• Django 2.2, 3.0, 3.1, 3.2, 4.0 and 4.1.
• Python 3.7, 3.8, 3.9, 3.10 and 3.11.

Dependencies

• djangorestframework: Initially written with 3.6.3, but nowadays tested with >=3.10,<3.14. May (still) work on earlier- or (even) support later- versions, although not guaranteed.

Installation

1. Install latest stable version from PyPI:

   pip install django-rest-framework-tricks

   or latest development version from GitHub:

   pip install https://github.com/barseghyanartur/django-rest-framework-tricks/archive/master.tar.gz

2. Add rest_framework and rest_framework_tricks to INSTALLED_APPS:

   INSTALLED_APPS = (
       # ...
       # REST framework
       'rest_framework',
   
       # REST framework tricks (this package)
       'rest_framework_tricks',
   
       # ...
   )

Documentation

Documentation is available on Read the Docs.

Main features and highlights

• Nested serializers: Nested (writable) serializers for non-relational fields.
• Ordering filter: Developer friendly names for ordering options (for instance, for related field names).
• File field with restrictions: Restrict the file field (in size).

Usage examples

Nested serializers

Nested serializers for non-relational fields.

Our imaginary Book model consists of the following (non-relational) Django model fields:

• title: CharField
• description: TextField
• summary: TextField
• publication_date: DateTimeField
• state: CharField (with choices)
• isbn: CharField
• price: DecimalField
• pages: IntegerField
• stock_count: IntegerField

In our REST API, we want to split the Book serializer into parts using nested serializers to have the following structure:

{
    "id": "",
    "title": "",
    "description": "",
    "summary": "",
    "publishing_information": {
        "publication_date": "",
        "isbn": "",
        "pages": ""
    },
    "stock_information": {
        "stock_count": "",
        "price": "",
        "state": ""
    }
}

Sample model

The only variation from standard implementation here is that we declare two NestedProxyField fields on the Book model level for to be used in BookSerializer serializer.

Note, that the change does not cause model change (no migrations or whatsoever).

Required imports

from django.db import models

from rest_framework_tricks.models.fields import NestedProxyField

Model definition

BOOK_PUBLISHING_STATUS_PUBLISHED = 'published'
BOOK_PUBLISHING_STATUS_NOT_PUBLISHED = 'not_published'
BOOK_PUBLISHING_STATUS_IN_PROGRESS = 'in_progress'
BOOK_PUBLISHING_STATUS_CHOICES = (
    (BOOK_PUBLISHING_STATUS_PUBLISHED, "Published"),
    (BOOK_PUBLISHING_STATUS_NOT_PUBLISHED, "Not published"),
    (BOOK_PUBLISHING_STATUS_IN_PROGRESS, "In progress"),
)
BOOK_PUBLISHING_STATUS_DEFAULT = BOOK_PUBLISHING_STATUS_PUBLISHED


class Book(models.Model):
    """Book."""

    title = models.CharField(max_length=100)
    description = models.TextField(null=True, blank=True)
    summary = models.TextField(null=True, blank=True)
    publication_date = models.DateField()
    state = models.CharField(max_length=100,
                             choices=BOOK_PUBLISHING_STATUS_CHOICES,
                             default=BOOK_PUBLISHING_STATUS_DEFAULT)
    isbn = models.CharField(max_length=100, unique=True)
    price = models.DecimalField(max_digits=10, decimal_places=2)
    pages = models.PositiveIntegerField(default=200)
    stock_count = models.PositiveIntegerField(default=30)

    # List the fields for `PublishingInformationSerializer` nested
    # serializer. This does not cause a model change.
    publishing_information = NestedProxyField(
        'publication_date',
        'isbn',
        'pages',
    )

    # List the fields for `StockInformationSerializer` nested serializer.
    # This does not cause a model change.
    stock_information = NestedProxyField(
        'stock_count',
        'price',
        'state',
    )

    class Meta:
        """Meta options."""

        ordering = ["isbn"]

    def __str__(self):
        return self.title

Sample serializers

At first, we add nested_proxy_field property to the Meta class definitions of PublishingInformationSerializer and StockInformationSerializer nested serializers.

Then we define our (main) BookSerializer class, which is going to be used as a serializer_class of the BookViewSet. We inherit the BookSerializer from rest_framework_tricks.serializers.HyperlinkedModelSerializer instead of the one of the Django REST framework. There's also a rest_framework_tricks.serializers.ModelSerializer available.

Required imports

from rest_framework import serializers
from rest_framework_tricks.serializers import (
    HyperlinkedModelSerializer,
)

from .models import Book

Defining the serializers

Note

If you get validation errors about null-values, add allow_null=True next to the required=False for serializer field definitions.

Nested serializer

class PublishingInformationSerializer(serializers.ModelSerializer):
    """Publishing information serializer."""

    publication_date = serializers.DateField(required=False)
    isbn = serializers.CharField(required=False)
    pages = serializers.IntegerField(required=False)

    class Meta:
        """Meta options."""

        model = Book
        fields = (
            'publication_date',
            'isbn',
            'pages',
        )
        # Note, that this should be set to True to identify that
        # this serializer is going to be used as `NestedProxyField`.
        nested_proxy_field = True

Nested serializer

class StockInformationSerializer(serializers.ModelSerializer):
    """Stock information serializer."""

    class Meta:
        """Meta options."""

        model = Book
        fields = (
            'stock_count',
            'price',
            'state',
        )
        # Note, that this should be set to True to identify that
        # this serializer is going to be used as `NestedProxyField`.
        nested_proxy_field = True

Main serializer to be used in the ViewSet

# Note, that we are importing the ``HyperlinkedModelSerializer`` from
# the `rest_framework_tricks.serializers`. Names of the serializers
# should match the names of model properties set with ``NestedProxyField``
# fields.
class BookSerializer(HyperlinkedModelSerializer):
    """Book serializer."""

    publishing_information = PublishingInformationSerializer(required=False)
    stock_information = StockInformationSerializer(required=False)

    class Meta:
        """Meta options."""

        model = Book
        fields = (
            'url',
            'id',
            'title',
            'description',
            'summary',
            'publishing_information',
            'stock_information',
        )

Sample ViewSet

Absolutely no variations from standard implementation here.

Required imports

from rest_framework.viewsets import ModelViewSet
from rest_framework.permissions import AllowAny

from .models import Book
from .serializers import BookSerializer

ViewSet definition

class BookViewSet(ModelViewSet):
    """Book ViewSet."""

    queryset = Book.objects.all()
    serializer_class = BookSerializer
    permission_classes = [AllowAny]

Sample OPTIONS call

OPTIONS /books/api/books/
HTTP 200 OK
Allow: GET, POST, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "name": "Book List",
    "description": "Book ViewSet.",
    "renders": [
        "application/json",
        "text/html"
    ],
    "parses": [
        "application/json",
        "application/x-www-form-urlencoded",
        "multipart/form-data"
    ],
    "actions": {
        "POST": {
            "id": {
                "type": "integer",
                "required": false,
                "read_only": true,
                "label": "ID"
            },
            "title": {
                "type": "string",
                "required": true,
                "read_only": false,
                "label": "Title",
                "max_length": 100
            },
            "description": {
                "type": "string",
                "required": false,
                "read_only": false,
                "label": "Description"
            },
            "summary": {
                "type": "string",
                "required": false,
                "read_only": false,
                "label": "Summary"
            },
            "publishing_information": {
                "type": "nested object",
                "required": false,
                "read_only": false,
                "label": "Publishing information",
                "children": {
                    "publication_date": {
                        "type": "date",
                        "required": false,
                        "read_only": false,
                        "label": "Publication date"
                    },
                    "isbn": {
                        "type": "string",
                        "required": false,
                        "read_only": false,
                        "label": "Isbn"
                    },
                    "pages": {
                        "type": "integer",
                        "required": false,
                        "read_only": false,
                        "label": "Pages"
                    }
                }
            },
            "stock_information": {
                "type": "nested object",
                "required": false,
                "read_only": false,
                "label": "Stock information",
                "children": {
                    "stock_count": {
                        "type": "integer",
                        "required": false,
                        "read_only": false,
                        "label": "Stock count"
                    },
                    "price": {
                        "type": "decimal",
                        "required": true,
                        "read_only": false,
                        "label": "Price"
                    },
                    "state": {
                        "type": "choice",
                        "required": false,
                        "read_only": false,
                        "label": "State",
                        "choices": [
                            {
                                "value": "published",
                                "display_name": "Published"
                            },
                            {
                                "value": "not_published",
                                "display_name": "Not published"
                            },
                            {
                                "value": "in_progress",
                                "display_name": "In progress"
                            }
                        ]
                    }
                }
            }
        }
    }
}

Unlimited nesting depth

Unlimited nesting depth is supported.

Our imaginary Author model could consist of the following (non-relational) Django model fields:

• salutation: CharField
• name: CharField
• email: EmailField
• birth_date: DateField
• biography: TextField
• phone_number: CharField
• website: URLField
• company: CharField
• company_phone_number: CharField
• company_email: EmailField
• company_website: URLField

In our REST API, we could split the Author serializer into parts using nested serializers to have the following structure:

{
    "id": "",
    "salutation": "",
    "name": "",
    "birth_date": "",
    "biography": "",
    "contact_information": {
        "personal_contact_information": {
            "email": "",
            "phone_number": "",
            "website": ""
        },
        "business_contact_information": {
            "company": "",
            "company_email": "",
            "company_phone_number": "",
            "company_website": ""
        }
    }
}

Our model would have to be defined as follows (see Advanced usage examples for complete model definition):

class Author(models.Model):
    """Author."""

    # ...

    # List the fields for `PersonalContactInformationSerializer` nested
    # serializer. This does not cause a model change.
    personal_contact_information = NestedProxyField(
        'email',
        'phone_number',
        'website',
    )

    # List the fields for `BusinessContactInformationSerializer` nested
    # serializer. This does not cause a model change.
    business_contact_information = NestedProxyField(
        'company',
        'company_email',
        'company_phone_number',
        'company_website',
    )

    # List the fields for `ContactInformationSerializer` nested
    # serializer. This does not cause a model change.
    contact_information = NestedProxyField(
        'personal_contact_information',
        'business_contact_information',
    )

    # ...

See the Advanced usage examples for complete example.

Ordering filter

Developer friendly names for ordering options (for instance, for related field names) for making better APIs.

Sample model

Absolutely no variations from standard implementation here.

Required imports

from django.db import models

Model definition

class Profile(models.Model):
    """Profile."""

    user = models.ForeignKey('auth.User')
    biography = models.TextField()
    hobbies = models.TextField()

Sample serializer

Absolutely no variations from standard implementation here.

Required imports

from rest_framework import serializers

from .models import Profile

Defining the serializers

class ProfileSerializer(serializers.ModelSerializer):
    """Profile serializer."""

    username = serializers.CharField(source='user.username', read_only=True)
    full_name = serializers.SerializerMethodField()
    email = serializers.CharField(source='user.email', read_only=True)

    class Meta(object):

    model = Profile
    fields = (
        'id',
        'username',
        'full_name',
        'email',
        'biography',
        'hobbies',
    )

    def get_full_name(self, obj):
        return obj.user.get_full_name()

Sample ViewSet

The only variation from standard implementation here is that we use rest_frameworks_tricks.filters.OrderingFilter instead of rest_framework.filters.OrderingFilter.

Required imports

from rest_framework.viewsets import ModelViewSet
from rest_framework.permissions import AllowAny
from rest_framework_tricks.filters import OrderingFilter

from .models import Profile
from .serializers import ProfileSerializer

ViewSet definition

class ProfileViewSet(ModelViewSet):
    """Profile ViewSet."""

    queryset = Profile.objects.all()
    serializer_class = ProfileSerializer
    permission_classes = [AllowAny]
    filter_backends = (OrderingFilter,)
    ordering_fields = {
        'id': 'id',
        'username': 'user__username',
        'email': 'user__email',
        'full_name': ['user__first_name', 'user__last_name']
    }
    ordering = ('id',)

Sample GET calls

Note, that our ordering options are now equal to the field names in the serializer (JSON response). API becomes easier to use/understand that way.

GET /api/profile/?ordering=email
GET /api/profile/?ordering=-username
GET /api/profile/?ordering=full_name
GET /api/profile/?ordering=-full_name

File field with restrictions

Sample model

Absolutely no variations from standard implementation here.

Required imports

from django.db import models

Model definition

class Profile(models.Model):
    """Upload."""

    username = models.CharField(max_length=255)
    resume = models.FileField()

Sample serializer

Required imports

from rest_framework import serializers
from rest_framework_tricks.fields import ConstrainedFileField

from .models import Upload

Defining the serializers

class ProfileSerializer(serializers.ModelSerializer):
    """Profile serializer."""

    username = serializers.CharField()
    # Restrict resume to 5Mb
    resume = ConstrainedFileField(max_upload_size=5_242_880)

    class Meta(object):

    model = Profile
    fields = (
        'id',
        'username',
        'resume',
    )

Demo

Run demo locally

In order to be able to quickly evaluate the django-rest-framework-tricks, a demo app (with a quick installer) has been created (works on Ubuntu/Debian, may work on other Linux systems as well, although not guaranteed). Follow the instructions below to have the demo running within a minute.

Grab and run the latest rest_framework_tricks_demo_installer.sh demo installer:

wget -O - https://raw.github.com/barseghyanartur/django-rest-framework-tricks/master/examples/rest_framework_tricks_demo_installer.sh | bash

Open your browser and test the app.

http://127.0.0.1:8001/books/api/

Testing

Project is covered with tests.

To test with all supported Python/Django versions type:

tox

To test against specific environment, type:

tox -e py39-django32

To test just your working environment type:

pytest -vvv

To run a single test in your working environment type:

pytest -vvv src/rest_framework_tricks/tests/test_nested_proxy_field.py

pip install -r examples/requirements/test.txt

Writing documentation

Keep the following hierarchy.

=====
title
=====

header
======

sub-header
----------

sub-sub-header
~~~~~~~~~~~~~~

sub-sub-sub-header
^^^^^^^^^^^^^^^^^^

sub-sub-sub-sub-header
++++++++++++++++++++++

sub-sub-sub-sub-sub-header
**************************

License

GPL-2.0-only OR LGPL-2.1-or-later

Support

For any security issues contact me at the e-mail given in the Author section.

For overall issues, go to GitHub.

Author

Artur Barseghyan <artur.barseghyan@gmail.com>