GitLocker: The Coding Marketplace

Description:

drfsideloading 2.0.1

:warning: Note that there are major API changes since version 0.1.1 that have to be taken into account when upgrading!
:warning: Python 2 and Django 1.11 are no longer supported from version 1.4.0!
Django rest framework sideloading
DRF-sideloading is an extension to provide side-loading functionality of related resources. Side-loading allows related resources to be optionally included in a single API response minimizing requests to the API.
Quickstart

Install drf-sideloading:
pip install drf-sideloading

Import SideloadableRelationsMixin:
from drf_sideloading.mixins import SideloadableRelationsMixin

Write your SideLoadableSerializer:
You need to define the primary serializer in the Meta data and can define prefetching rules.
Also notice the many=True on the sideloadable relationships.
from drf_sideloading.serializers import SideLoadableSerializer

class ProductSideloadableSerializer(SideLoadableSerializer):
products = ProductSerializer(many=True)
categories = CategorySerializer(source="category", many=True)
primary_suppliers = SupplierSerializer(source="primary_supplier", many=True)
secondary_suppliers = SupplierSerializer(many=True)
suppliers = SupplierSerializer(many=True)
partners = PartnerSerializer(many=True)

class Meta:
primary = "products"
prefetches = {
"categories": "category",
"primary_suppliers": "primary_supplier",
"secondary_suppliers": "secondary_suppliers",
"suppliers": {
"primary_suppliers": "primary_supplier",
"secondary_suppliers": "secondary_suppliers",
},
"partners": "partners",
}

Prefetches
For fields where the source is provided or where the source matches the field name, prefetches are not strictly required
Multiple prefetches can be added to a single sideloadable field, but when using Prefetch object check that they don't clash with prefetches made in the get_queryset() method
from django.db.models import Prefetch

prefetches = {
"categories": "category",
"primary_suppliers": ["primary_supplier", "primary_supplier__some_related_object"],
"secondary_suppliers": Prefetch(
lookup="secondary_suppliers",
queryset=Supplier.objects.prefetch_related("some_related_object")
),
"partners": Prefetch(
lookup="partners",
queryset=Partner.objects.select_related("some_related_object")
)
}

Multiple sources can be added to a field using a dict.
Each key is a source_key that can be used to filter what sources should be sideloaded.
The values set the source and prefetches for this source.
Note that this prefetch reuses primary_supplier and secondary_suppliers if suppliers and primary_supplier or secondary_suppliers are sideloaded
prefetches = {
"primary_suppliers": "primary_supplier",
"secondary_suppliers": "secondary_suppliers",
"suppliers": {
"primary_suppliers": "primary_supplier",
"secondary_suppliers": "secondary_suppliers"
}
}

Usage of Prefetch() objects is supported.
Prefetch() objects can be used to filter a subset of some relations or just to prefetch or select complicated related objects
In case there are prefetch conflicts, to_attr can be set but be aware that this prefetch will now be a duplicate of similar prefetches.
prefetch conflicts can also come from prefetched made in the ViewSet.get_queryset() method.
Note that this prefetch noes not reuse primary_supplier and secondary_suppliers if suppliers and primary_supplier or secondary_suppliers are sideloaded at the same time.
from django.db.models import Prefetch

prefetches = {
"categories": "category",
"primary_suppliers": "primary_supplier",
"secondary_suppliers": "secondary_suppliers",
"suppliers": {
"primary_suppliers": Prefetch(
lookup="secondary_suppliers",
queryset=Supplier.objects.select_related("some_related_object"),
to_attr="secondary_suppliers_with_preselected_relation"
),
"secondary_suppliers": Prefetch(
lookup="secondary_suppliers",
queryset=Supplier.objects.filter(created_at__gt=pendulum.now().subtract(days=10)).order_by("created_at"),
to_attr="latest_secondary_suppliers"
)
},
}

Configure sideloading in ViewSet:
Include SideloadableRelationsMixin mixin in ViewSet and define sideloading_serializer_class as shown in example below.
Everything else stays just like a regular ViewSet.
Since version 2.0.0 there are 3 new methods that allow to overwrite the serializer used based on the request version for example
from drf_sideloading.mixins import SideloadableRelationsMixin

class ProductViewSet(SideloadableRelationsMixin, viewsets.ModelViewSet):
"""
A simple ViewSet for viewing and editing products.
"""

queryset = Product.objects.all()
serializer_class = ProductSerializer
sideloading_serializer_class = ProductSideloadableSerializer

def get_queryset(self):
# Add prefetches for the viewset as normal
return super().get_queryset().prefetch_related("created_by")

def get_sideloading_serializer_class(self):
# use a different sideloadable serializer for older version
if self.request.version < "1.0.0":
return OldProductSideloadableSerializer
return super().get_sideloading_serializer_class()

def get_sideloading_serializer(self, *args, **kwargs):
# if modifications are required to the serializer initialization this method can be used.
return super().get_sideloading_serializer(*args, **kwargs)

def get_sideloading_serializer_context(self):
# Extra context provided to the serializer class.
return {"request": self.request, "format": self.format_kwarg, "view": self}

Enjoy your API with sideloading support
Example request and response when fetching all possible values
GET /api/products/?sideload=categories,partners,primary_suppliers,secondary_suppliers,suppliers,products

{
"products": [
{
"id": 1,
"name": "Product 1",
"category": 1,
"primary_supplier": 1,
"secondary_suppliers": [2, 3],
"partners": [1, 2, 3]
}
],
"categories": [
{
"id": 1,
"name": "Category1"
}
],
"primary_suppliers": [
{
"id": 1,
"name": "Supplier1"
}
],
"secondary_suppliers": [
{
"id": 2,
"name": "Supplier2"
},
{
"id": 3,
"name": "Supplier3"
}
],
"suppliers": [
{
"id": 1,
"name": "Supplier1"
},
{
"id": 2,
"name": "Supplier2"
},
{
"id": 3,
"name": "Supplier3"
}
],
"partners": [
{
"id": 1,
"name": "Partner1"
},
{
"id": 2,
"name": "Partner1"
},
{
"id": 3,
"name": "Partner3"
}
]
}

The user can also select what sources to load to Multi source fields.
Leaving the selections empty or omitting the brackets will load all the prefetched sources.
Example:
GET /api/products/?sideload=suppliers[primary_suppliers]

{
"products": [
{
"id": 1,
"name": "Product 1",
"category": 1,
"primary_supplier": 1,
"secondary_suppliers": [2, 3],
"partners": [1, 2, 3]
}
],
"suppliers": [
{
"id": 1,
"name": "Supplier1"
}
]
}

Example Project
Directory example contains an example project using django rest framework sideloading library. You can set it up and run it locally using following commands:
cd example
sh scripts/devsetup.sh
sh scripts/dev.sh

Contributing
Contributions are welcome, and they are greatly appreciated! Every little bit helps, and credit will always be given.
Setup for contribution
source <YOURVIRTUALENV>/bin/activate
(myenv) $ pip install -r requirements_dev.txt

Test
$ make test

Run tests with environment matrix
$ make tox

Run tests with specific environment
$ tox --listenvs
py37-django22-drf39
py38-django31-drf311
py39-django32-drf312
# ...
$ tox -e py39-django32-drf312

Test coverage
$ make coverage

Use pyenv for testing using different python versions locally.
License
MIT
Credits

Demur Nodia
Tõnis Väin
Madis Väin
Lenno Nagel

Changelog
2.0.1 (2021-12-16)

Ensure that only allowed methods are sideloaded

2.0.0 (2021-12-10)
Major refactoring to allow for multi source fields.

Add support for multi source fields
Add support for detail view sideloading
Dropped formless BrowsableAPIRenderer enforcement
Raises error in case invalid fields are requested for sideloading

1.4.2 (2021-04-12)

Add support for lists in filter_related_objects

1.4.1 (2021-04-09)

Fix sideloadable prefetches

1.4.0 (2021-04-07)

Python supported versions 3.6 -> 3.9
Django supported versions 2.2, 3.1, 3.2
Django-rest-framework supported versions. 3.9 -> 3.12

1.3.1 (2021-04-07)
Added support for django.db.models.Prefetch
1.3.0 (2019-04-23)
Fix empty related fields sideloading bug

Support for Django 2.2

1.2.0 (2018-10-29)
Completely refactored sideloading configuration via a custom serializer.

Support for Django 2.1
Support for Django-rest-framework 3.9

0.1.10 (2017-07-20)

Support for Django 2.0

0.1.8 (2017-07-20)

change sideloadable_relations dict
always required to define 'serializer'
key is referenced to url and serialized in as rendered json
add source which specifies original model field name

0.1.0 (2017-07-20)

First release on PyPI.