The DJA package implements a custom renderer, parser, exception handler, query filter backends, and
pagination. To get started enable the pieces in settings.py that you want to use.
Many features of the JSON:API format standard have been implemented using
Mixin classes in serializers.py.
The easiest way to make use of those features is to import ModelSerializer variants
from rest_framework_json_api instead of the usual rest_framework
We suggest that you copy the settings block below and modify it if necessary.
REST_FRAMEWORK = {
'PAGE_SIZE': 10,
'EXCEPTION_HANDLER': 'rest_framework_json_api.exceptions.exception_handler',
'DEFAULT_PAGINATION_CLASS':
'rest_framework_json_api.pagination.JsonApiPageNumberPagination',
'DEFAULT_PARSER_CLASSES': (
'rest_framework_json_api.parsers.JSONParser',
'rest_framework.parsers.FormParser',
'rest_framework.parsers.MultiPartParser'
),
'DEFAULT_RENDERER_CLASSES': (
'rest_framework_json_api.renderers.JSONRenderer',
# If you're performance testing, you will want to use the browseable API
# without forms, as the forms can generate their own queries.
# If performance testing, enable:
# 'example.utils.BrowsableAPIRendererWithoutForms',
# Otherwise, to play around with the browseable API, enable:
'rest_framework_json_api.renderers.BrowsableAPIRenderer'
),
'DEFAULT_METADATA_CLASS': 'rest_framework_json_api.metadata.JSONAPIMetadata',
'DEFAULT_FILTER_BACKENDS': (
'rest_framework_json_api.filters.QueryParameterValidationFilter',
'rest_framework_json_api.filters.OrderingFilter',
'rest_framework_json_api.django_filters.DjangoFilterBackend',
'rest_framework.filters.SearchFilter',
),
'SEARCH_PARAM': 'filter[search]',
'TEST_REQUEST_RENDERER_CLASSES': (
'rest_framework_json_api.renderers.JSONRenderer',
),
'TEST_REQUEST_DEFAULT_FORMAT': 'vnd.api+json'
}DJA pagination is based on DRF pagination.
When pagination is enabled, the renderer will return a meta object with
record count and a links object with the next, previous, first, and last links.
Optional query parameters can also be provided to customize the page size or offset limit.
Pagination style can be set on a particular viewset with the pagination_class attribute or by default for all viewsets
by setting REST_FRAMEWORK['DEFAULT_PAGINATION_CLASS'] and by setting REST_FRAMEWORK['PAGE_SIZE'].
You can configure fixed values for the page size or limit -- or allow the client to choose the size or limit via query parameters.
Two pagination classes are available:
-
JsonApiPageNumberPaginationbreaks a response up into pages that start at a given page number with a given size (number of items per page). It can be configured with the following attributes:page_query_param(defaultpage[number])page_size_query_param(defaultpage[size]) Set this toNoneif you don't want to allow the client to specify the size.page_size(defaultREST_FRAMEWORK['PAGE_SIZE']) default number of items per page unless overridden bypage_size_query_param.max_page_size(default100) enforces an upper bound on thepage_size_query_param. Set it toNoneif you don't want to enforce an upper bound.
-
JsonApiLimitOffsetPaginationbreaks a response up into pages that start from an item's offset in the viewset for a given number of items (the limit). It can be configured with the following attributes:offset_query_param(defaultpage[offset]).limit_query_param(defaultpage[limit]).default_limit(defaultREST_FRAMEWORK['PAGE_SIZE']) is the default number of items per page unless overridden bylimit_query_param.max_limit(default100) enforces an upper bound on the limit. Set it toNoneif you don't want to enforce an upper bound.
These examples show how to configure the parameters to use non-standard names and different limits:
from rest_framework_json_api.pagination import JsonApiPageNumberPagination, JsonApiLimitOffsetPagination
class MyPagePagination(JsonApiPageNumberPagination):
page_query_param = 'page_number'
page_size_query_param = 'page_length'
page_size = 3
max_page_size = 1000
class MyLimitPagination(JsonApiLimitOffsetPagination):
offset_query_param = 'offset'
limit_query_param = 'limit'
default_limit = 3
max_limit = NoneFollowing are descriptions of JSON:API-specific filter backends and documentation on suggested usage for a standard DRF keyword-search filter backend that makes it consistent with JSON:API.
QueryParameterValidationFilter validates query parameters to be one of the defined JSON:API query parameters
(sort, include, filter, fields, page) and returns a 400 Bad Request if a non-matching query parameter
is used. This can help the client identify misspelled query parameters, for example.
If you want to change the list of valid query parameters, override the .query_regex attribute:
# compiled regex that matches the allowed https://jsonapi.org/format/#query-parameters
# `sort` and `include` stand alone; `filter`, `fields`, and `page` have []'s
query_regex = re.compile(r"^(sort|include)$|^(?P<type>filter|fields|page)(\[[\w\.\-]+\])?$")For example:
import re
from rest_framework_json_api.filters import QueryParameterValidationFilter
class MyQPValidator(QueryParameterValidationFilter):
query_regex = re.compile(r"^(sort|include|page|page_size)$|^(?P<type>filter|fields|page)(\[[\w\.\-]+\])?$")If you don't care if non-JSON:API query parameters are allowed (and potentially silently ignored), simply don't use this filter backend.
OrderingFilter implements the JSON:API sort and uses
DRF's ordering filter.
Per the JSON:API specification, "If the server does not support sorting as specified in the query parameter sort,
it MUST return 400 Bad Request." For example, for ?sort=abc,foo,def where foo is a valid
field name and the other two are not valid:
{
"errors": [
{
"detail": "invalid sort parameters: abc,def",
"source": {
"pointer": "/data"
},
"status": "400"
}
]
}If you want to silently ignore bad sort fields, just use rest_framework.filters.OrderingFilter and set
ordering_param to sort.
DjangoFilterBackend implements a Django ORM-style JSON:API filter
using the django-filter package.
This filter is not part of the JSON:API standard per-se, other than the requirement
to use the filter keyword: It is an optional implementation of a style of
filtering in which each filter is an ORM expression as implemented by
DjangoFilterBackend and seems to be in alignment with an interpretation of the
JSON:API recommendations, including relationship
chaining.
Filters can be:
- A resource field equality test:
?filter[qty]=123 - Apply other field lookup operators:
?filter[name.icontains]=baror?filter[name.isnull]=true - Membership in a list of values:
?filter[name.in]=abc,123,zzz (name in ['abc','123','zzz']) - Filters can be combined for intersection (AND):
?filter[qty]=123&filter[name.in]=abc,123,zzz&filter[...]or?filter[authors.id]=1&filter[authors.id]=2 - A related resource path can be used:
?filter[inventory.item.partNum]=123456(whereinventory.itemis the relationship path)
The filter returns a 400 Bad Request error for invalid filter query parameters as in this example
for GET http://127.0.0.1:8000/nopage-entries?filter[bad]=1:
{
"errors": [
{
"detail": "invalid filter[bad]",
"source": {
"pointer": "/data"
},
"status": "400"
}
]
}As this feature depends on django-filter you need to run
pip install djangorestframework-jsonapi['django-filter']
To comply with JSON:API query parameter naming standards, DRF's
SearchFilter should
be configured to use a filter[_something_] query parameter. This can be done by default by adding the
SearchFilter to REST_FRAMEWORK['DEFAULT_FILTER_BACKENDS'] and setting REST_FRAMEWORK['SEARCH_PARAM'] or
adding the .search_param attribute to a custom class derived from SearchFilter. If you do this and also
use DjangoFilterBackend, make sure you set the same values for both classes.
You can configure the filter backends either by setting the REST_FRAMEWORK['DEFAULT_FILTER_BACKENDS'] as shown
in the example settings or individually add them as .filter_backends View attributes:
from rest_framework_json_api import filters
from rest_framework_json_api import django_filters
from rest_framework import SearchFilter
from models import MyModel
class MyViewset(ModelViewSet):
queryset = MyModel.objects.all()
serializer_class = MyModelSerializer
filter_backends = (filters.QueryParameterValidationFilter, filters.OrderingFilter,
django_filters.DjangoFilterBackend, SearchFilter)
filterset_fields = {
'id': ('exact', 'lt', 'gt', 'gte', 'lte', 'in'),
'descriptuon': ('icontains', 'iexact', 'contains'),
'tagline': ('icontains', 'iexact', 'contains'),
}
search_fields = ('id', 'description', 'tagline',)For the exception_handler class, if the optional JSON_API_UNIFORM_EXCEPTIONS is set to True,
all exceptions will respond with the JSON:API error format.
When JSON_API_UNIFORM_EXCEPTIONS is False (the default), non-JSON:API views will respond
with the normal DRF error format.
In case you need a custom error object you can simply raise an rest_framework.serializers.ValidationError like the following:
raise serializers.ValidationError(
{
"id": "your-id",
"detail": "your detail message",
"source": {
"pointer": "/data/attributes/your-pointer",
}
}
)If you are trying to see if your viewsets are configured properly to optimize performance,
it is preferable to use example.utils.BrowsableAPIRendererWithoutForms instead of the default BrowsableAPIRenderer
to remove queries introduced by the forms themselves.
It is recommended to import the base serializer classes from this package rather than from vanilla DRF. For example,
from rest_framework_json_api import serializers
class MyModelSerializer(serializers.ModelSerializer):
# ...Per default the primary key property pk on the instance is used as the resource identifier.
It is possible to overwrite the resource id by defining an id field on the serializer like:
class UserSerializer(serializers.ModelSerializer):
id = serializers.CharField(source='email')
name = serializers.CharField()
class Meta:
model = UserThis also works on generic serializers.
In case you also use a model as a resource related field make sure to overwrite get_resource_id by creating a custom ResourceRelatedField class:
class UserResourceRelatedField(ResourceRelatedField):
def get_resource_id(self, value):
return value.email
class GroupSerializer(serializers.ModelSerializer):
user = UserResourceRelatedField(queryset=User.objects)
name = serializers.CharField()
class Meta:
model = GroupYou may manually set resource identifier object type by using resource_name property on views, serializers, or
models. In case of setting the resource_name property for models you must include the property inside a
JSONAPIMeta class on the model. It is usually automatically set for you as the plural of the view or model name except
on resources that do not subclass rest_framework.viewsets.ModelViewSet:
Example - resource_name on View:
class Me(generics.GenericAPIView):
"""
Current user's identity endpoint.
GET /me
"""
resource_name = 'users'
serializer_class = identity_serializers.IdentitySerializer
allowed_methods = ['GET']
permission_classes = (permissions.IsAuthenticated, )Example - resource_name on Model:
class Me(models.Model):
"""
A simple model
"""
name = models.CharField(max_length=100)
class JSONAPIMeta:
resource_name = "users"If you set the resource_name on a combination of model, serializer, or view
in the same hierarchy, the name will be resolved as following: view >
serializer > model. (Ex: A view resource_name will always override a
resource_name specified on a serializer or model). Setting the resource_name
on the view should be used sparingly as serializers and models are shared between
multiple endpoints. Setting the resource_name on views may result in a different
type being set depending on which endpoint the resource is fetched from.
If in a view you want to build the output manually, you can set resource_name to False.
Example:
class User(ModelViewSet):
resource_name = False
queryset = User.objects.all()
serializer_class = UserSerializer
def retrieve(self, request, *args, **kwargs):
instance = self.get_object()
data = [{"id": 1, "type": "users", "attributes": {"fullName": "Test User"}}])This package includes the ability (off by default) to automatically convert JSON:API field names of requests and responses from the Django REST framework's preferred underscore to a format of your choice. To hook this up include the following setting in your project settings:
JSON_API_FORMAT_FIELD_NAMES = 'dasherize'Possible values:
- dasherize
- camelize (first letter is lowercase)
- capitalize (camelize but with first letter uppercase)
- underscore
Note: due to the way the inflector works address_1 can camelize to address1
on output but it cannot convert address1 back to address_1 on POST or PATCH. Keep
this in mind when naming fields with numbers in them.
Example - Without format conversion:
{
"data": [{
"type": "identities",
"id": "3",
"attributes": {
"username": "john",
"first_name": "John",
"last_name": "Coltrane",
"full_name": "John Coltrane"
},
}],
"meta": {
"pagination": {
"count": 20
}
}
}Example - With format conversion set to dasherize:
{
"data": [{
"type": "identities",
"id": "3",
"attributes": {
"username": "john",
"first-name": "John",
"last-name": "Coltrane",
"full-name": "John Coltrane"
},
}],
"meta": {
"pagination": {
"count": 20
}
}
}A similar option to JSON_API_FORMAT_FIELD_NAMES can be set for the types:
JSON_API_FORMAT_TYPES = 'dasherize'Example without format conversion:
{
"data": [{
"type": "blog_identity",
"id": "3",
"attributes": {
...
},
"relationships": {
"home_town": {
"data": [{
"type": "home_town",
"id": 3
}]
}
}
}]
}When set to dasherize:
{
"data": [{
"type": "blog-identity",
"id": "3",
"attributes": {
...
},
"relationships": {
"home_town": {
"data": [{
"type": "home-town",
"id": 3
}]
}
}
}]
}It is also possible to pluralize the types like so:
JSON_API_PLURALIZE_TYPES = TrueExample without pluralization:
{
"data": [{
"type": "identity",
"id": "3",
"attributes": {
...
},
"relationships": {
"home_towns": {
"data": [{
"type": "home_town",
"id": "3"
}]
}
}
}]
}When set to pluralize:
{
"data": [{
"type": "identities",
"id": "3",
"attributes": {
...
},
"relationships": {
"home_towns": {
"data": [{
"type": "home_towns",
"id": "3"
}]
}
}
}]
}Serializer properties in relationship and related resource URLs may be infected using the JSON_API_FORMAT_RELATED_LINKS setting.
JSON_API_FORMAT_RELATED_LINKS = 'dasherize'For example, with a serializer property created_by and with 'dasherize' formatting:
{
"data": {
"type": "comments",
"id": "1",
"attributes": {
"text": "Comments are fun!"
},
"links": {
"self": "/comments/1"
},
"relationships": {
"created_by": {
"links": {
"self": "/comments/1/relationships/created-by",
"related": "/comments/1/created-by"
}
}
}
},
"links": {
"self": "/comments/1"
}
}The relationship name is formatted by the JSON_API_FORMAT_FIELD_NAMES setting, but the URL segments are formatted by the JSON_API_FORMAT_RELATED_LINKS setting.
Because of the additional structure needed to represent relationships in JSON:API, this package provides the ResourceRelatedField for serializers, which
works similarly to PrimaryKeyRelatedField. By default,
rest_framework_json_api.serializers.ModelSerializer will use this for
related fields automatically. It can be instantiated explicitly as in the
following example:
from rest_framework_json_api import serializers
from rest_framework_json_api.relations import ResourceRelatedField
from myapp.models import Order, LineItem, Customer
class OrderSerializer(serializers.ModelSerializer):
class Meta:
model = Order
line_items = ResourceRelatedField(
queryset=LineItem.objects,
many=True # necessary for M2M fields & reverse FK fields
)
customer = ResourceRelatedField(
queryset=Customer.objects # queryset argument is required
) # except when read_only=TrueIn the JSON:API spec,
relationship objects contain links to related objects. To make this work
on a serializer we need to tell the ResourceRelatedField about the
corresponding view. Use the HyperlinkedModelSerializer and instantiate
the ResourceRelatedField with the relevant keyword arguments:
from rest_framework_json_api import serializers
from rest_framework_json_api.relations import ResourceRelatedField
from myapp.models import Order, LineItem, Customer
class OrderSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = Order
line_items = ResourceRelatedField(
queryset=LineItem.objects,
many=True,
related_link_view_name='order-lineitems-list',
related_link_url_kwarg='order_pk',
self_link_view_name='order_relationships'
)
customer = ResourceRelatedField(
queryset=Customer.objects,
related_link_view_name='order-customer-detail',
related_link_url_kwarg='order_pk',
self_link_view_name='order-relationships'
)-
related_link_view_nameis the name of the route for the related view. -
related_link_url_kwargis the keyword argument that will be passed to the view that identifies the 'parent' object, so that the results can be filtered to show only those objects related to the 'parent'. -
self_link_view_nameis the name of the route for theRelationshipView(see below).
In this example, reverse('order-lineitems-list', kwargs={'order_pk': 3}
should resolve to something like /orders/3/lineitems, and that route
should instantiate a view or viewset for LineItem objects that accepts
a keyword argument order_pk. The
drf-nested-routers package
is useful for defining such nested routes in your urlconf.
The corresponding viewset for the line-items-list route in the above example
might look like the following. Note that in the typical use case this would be
the same viewset used for the /lineitems endpoints; when accessed through
the nested route /orders/<order_pk>/lineitems the queryset is filtered using
the order_pk keyword argument to include only the lineitems related to the
specified order.
from rest_framework import viewsets
from myapp.models import LineItem
from myapp.serializers import LineItemSerializer
class LineItemViewSet(viewsets.ModelViewSet):
queryset = LineItem.objects
serializer_class = LineItemSerializer
def get_queryset(self):
queryset = super().get_queryset()
# if this viewset is accessed via the 'order-lineitems-list' route,
# it wll have been passed the `order_pk` kwarg and the queryset
# needs to be filtered accordingly; if it was accessed via the
# unnested '/lineitems' route, the queryset should include all LineItems
order_pk = self.kwargs.get('order_pk')
if order_pk is not None:
queryset = queryset.filter(order__pk=order_pk)
return querysetrelations.HyperlinkedRelatedField has same functionality as ResourceRelatedField but does
not render data. Use this in case you only need links of relationships and want to lower payload
and increase performance.
relations.SerializerMethodResourceRelatedField combines behaviour of DRF SerializerMethodField and
ResourceRelatedField, so it accepts method_name together with model and links-related arguments.
data is rendered in ResourceRelatedField manner.
from rest_framework_json_api import serializers
from rest_framework_json_api.relations import SerializerMethodResourceRelatedField
from myapp.models import Order, LineItem
class OrderSerializer(serializers.ModelSerializer):
class Meta:
model = Order
line_items = SerializerMethodResourceRelatedField(
model=LineItem,
many=True,
method_name='get_big_line_items'
)
small_line_items = SerializerMethodResourceRelatedField(
model=LineItem,
many=True,
# default to method_name='get_small_line_items'
)
def get_big_line_items(self, instance):
return LineItem.objects.filter(order=instance).filter(amount__gt=1000)
def get_small_line_items(self, instance):
return LineItem.objects.filter(order=instance).filter(amount__lte=1000)or using related_link_* with HyperlinkedModelSerializer
class OrderSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = Order
line_items = SerializerMethodResourceRelatedField(
model=LineItem,
many=True,
method_name='get_big_line_items',
related_link_view_name='order-lineitems-list',
related_link_url_kwarg='order_pk',
)
def get_big_line_items(self, instance):
return LineItem.objects.filter(order=instance).filter(amount__gt=1000)There is a nice way to handle "related" urls like /orders/3/lineitems/ or /orders/3/customer/.
All you need is just add to urls.py:
url(r'^orders/(?P<pk>[^/.]+)/$',
OrderViewSet.as_view({'get': 'retrieve'}),
name='order-detail'),
url(r'^orders/(?P<pk>[^/.]+)/(?P<related_field>[-\w]+)/$',
OrderViewSet.as_view({'get': 'retrieve_related'}),
name='order-related'),Make sure that RelatedField declaration has related_link_url_kwarg='pk' or simply skipped (will be set by default):
line_items = ResourceRelatedField(
queryset=LineItem.objects,
many=True,
related_link_view_name='order-related',
related_link_url_kwarg='pk',
self_link_view_name='order-relationships'
)
customer = ResourceRelatedField(
queryset=Customer.objects,
related_link_view_name='order-related',
self_link_view_name='order-relationships'
)And, the most important part - declare serializer for each related entity:
class OrderSerializer(serializers.HyperlinkedModelSerializer):
...
related_serializers = {
'customer': 'example.serializers.CustomerSerializer',
'line_items': 'example.serializers.LineItemSerializer'
}Or, if you already have included_serializers declared and your related_serializers look the same, just skip it:
class OrderSerializer(serializers.HyperlinkedModelSerializer):
...
included_serializers = {
'customer': 'example.serializers.CustomerSerializer',
'line_items': 'example.serializers.LineItemSerializer'
}rest_framework_json_api.views.RelationshipView is used to build
relationship views (see the
JSON:API spec).
The self link on a relationship object should point to the corresponding
relationship view.
The relationship view is fairly simple because it only serializes Resource Identifier Objects rather than full resource objects. In most cases the following is sufficient:
from rest_framework_json_api.views import RelationshipView
from myapp.models import Order
class OrderRelationshipView(RelationshipView):
queryset = Order.objectsThe urlconf would need to contain a route like the following:
url(
regex=r'^orders/(?P<pk>[^/.]+)/relationships/(?P<related_field>[-/w]+)$',
view=OrderRelationshipView.as_view(),
name='order-relationships'
)The related_field kwarg specifies which relationship to use, so
if we are interested in the relationship represented by the related
model field Order.line_items on the Order with pk 3, the url would be
/orders/3/relationships/line_items. On HyperlinkedModelSerializer, the
ResourceRelatedField will construct the url based on the provided
self_link_view_name keyword argument, which should match the name=
provided in the urlconf, and will use the name of the field for the
related_field kwarg.
Also we can override related_field in the url. Let's say we want the url to be:
/order/3/relationships/order_items - all we need to do is just add field_name_mapping
dict to the class:
field_name_mapping = {
'order_items': 'line_items'
}Polymorphic resources allow you to use specialized subclasses without requiring
special endpoints to expose the specialized versions. For example, if you had a
Project that could be either an ArtProject or a ResearchProject, you can
have both kinds at the same URL.
DJA tests its polymorphic support against django-polymorphic. The polymorphic feature should also work with other popular libraries like django-polymodels or django-typed-models.
As this feature depends on django-polymorphic you need to run
pip install djangorestframework-jsonapi['django-polymorphic']
A polymorphic endpoint can be set up if associated with a polymorphic serializer. A polymorphic serializer takes care of (de)serializing the correct instances types and can be defined like this:
class ProjectSerializer(serializers.PolymorphicModelSerializer):
polymorphic_serializers = [ArtProjectSerializer, ResearchProjectSerializer]
class Meta:
model = models.ProjectIt must inherit from serializers.PolymorphicModelSerializer and define the polymorphic_serializers list.
This attribute defines the accepted resource types.
Polymorphic relations can also be handled with relations.PolymorphicResourceRelatedField like this:
class CompanySerializer(serializers.ModelSerializer):
current_project = relations.PolymorphicResourceRelatedField(
ProjectSerializer, queryset=models.Project.objects.all())
future_projects = relations.PolymorphicResourceRelatedField(
ProjectSerializer, queryset=models.Project.objects.all(), many=True)
class Meta:
model = models.CompanyThey must be explicitly declared with the polymorphic_serializer (first positional argument) correctly defined.
It must be a subclass of serializers.PolymorphicModelSerializer.
resource_name
defined on the view.
You may add metadata to the rendered json in two different ways: meta_fields and get_root_meta.
On any rest_framework_json_api.serializers.ModelSerializer you may add a meta_fields
property to the Meta class. This behaves in the same manner as the default
fields property and will cause SerializerMethodFields or model values to be
added to the meta object within the same data as the serializer.
To add metadata to the top level meta object add:
def get_root_meta(self, resource, many):
if many:
# Dealing with a list request
return {
'size': len(resource)
}
else:
# Dealing with a detail request
return {
'foo': 'bar'
}to the serializer. It must return a dict and will be merged with the existing top level meta.
To access metadata in incoming requests, the JSONParser will add the metadata under a top level _meta key in the parsed data dictionary. For instance, to access meta data from a serializer object, you may use serializer.initial_data.get("_meta"). To customize the _meta key, see here.
Adding url to fields on a serializer will add a self link to the links key.
Related links will be created automatically when using the Relationship View.
JSON:API can include additional resources in a single network request.
The specification refers to this feature as
Compound Documents.
Compound Documents can reduce the number of network requests
which can lead to a better performing web application.
To accomplish this,
the specification permits a top level included key.
The list of content within this key are the extra resources
that are related to the primary resource.
To make a Compound Document,
you need to modify your ModelSerializer.
included_serializers is required to inform DJA of what and how you would like
to include.
included_resources tells DJA what you want to include by default.
For example, suppose you are making an app to go on quests, and you would like to fetch your chosen knight along with the quest. You could accomplish that with:
class KnightSerializer(serializers.ModelSerializer):
class Meta:
model = Knight
fields = ('id', 'name', 'strength', 'dexterity', 'charisma')
class QuestSerializer(serializers.ModelSerializer):
included_serializers = {
'knight': KnightSerializer,
}
class Meta:
model = Quest
fields = ('id', 'title', 'reward', 'knight')
class JSONAPIMeta:
included_resources = ['knight']Be aware that using included resources without any form of prefetching WILL HURT PERFORMANCE as it will introduce m*(n+1) queries.
A viewset helper was therefore designed to automatically preload data when possible. Such is automatically available when subclassing ModelViewSet or ReadOnlyModelViewSet.
It also allows to define custom select_related and prefetch_related for each requested include when needed in special cases:
rest_framework_json_api.views.ModelViewSet:
from rest_framework_json_api import views
# When MyViewSet is called with ?include=author it will dynamically prefetch author and author.bio
class MyViewSet(views.ModelViewSet):
queryset = Book.objects.all()
select_for_includes = {
'author': ['author__bio'],
}
prefetch_for_includes = {
'__all__': [],
'all_authors': [Prefetch('all_authors', queryset=Author.objects.select_related('bio'))],
'category.section': ['category']
}An additional convenience DJA class exists for read-only views, just as it does in DRF.
from rest_framework_json_api import views
class MyReadOnlyViewSet(views.ReadOnlyModelViewSet):
# ...The special keyword __all__ can be used to specify a prefetch which should be done regardless of the include, similar to making the prefetch yourself on the QuerySet.
Using the helper to prefetch, rather than attempting to minimise queries via select_related might give you better performance depending on the characteristics of your data and database.
For example:
If you have a single model, e.g. Book, which has four relations e.g. Author, Publisher, CopyrightHolder, Category.
To display 25 books and related models, you would need to either do:
a) 1 query via selected_related, e.g. SELECT * FROM books LEFT JOIN author LEFT JOIN publisher LEFT JOIN CopyrightHolder LEFT JOIN Category
b) 4 small queries via prefetch_related.
If you have 1M books, 50k authors, 10k categories, 10k copyrightholders
in the select_related scenario, you've just created a in-memory table
with 1e18 rows which will likely exhaust any available memory and
slow your database to crawl.
The prefetch_related case will issue 4 queries, but they will be small and fast queries.
DRF has a OAS schema functionality to generate an OAS 3.0 schema as a YAML or JSON file.
DJA extends DRF's schema support to generate an OAS schema in the JSON:API format.
Deprecation notice:
REST framework's built-in support for generating OpenAPI schemas is deprecated in favor of 3rd party packages that can provide this functionality instead. Therefore we have also deprecated the schema support in Django REST framework JSON:API. The built-in support will be retired over the next releases.
As a full-fledged replacement, we recommend the drf-spectacular-json-api package.
In order to produce an OAS schema that properly represents the JSON:API structure
you have to either add a schema attribute to each view class or set the REST_FRAMEWORK['DEFAULT_SCHEMA_CLASS']
to DJA's version of AutoSchema.
from rest_framework_json_api.schemas.openapi import AutoSchema
class MyViewset(ModelViewSet):
schema = AutoSchema
...REST_FRAMEWORK = {
# ...
'DEFAULT_SCHEMA_CLASS': 'rest_framework_json_api.schemas.openapi.AutoSchema',
}You can extend the OAS schema document by subclassing
SchemaGenerator
and extending get_schema.
Here's an example that adds OAS info and servers objects.
from rest_framework_json_api.schemas.openapi import SchemaGenerator as JSONAPISchemaGenerator
class MySchemaGenerator(JSONAPISchemaGenerator):
"""
Describe my OAS schema info in detail (overriding what DRF put in) and list the servers where it can be found.
"""
def get_schema(self, request, public):
schema = super().get_schema(request, public)
schema['info'] = {
'version': '1.0',
'title': 'my demo API',
'description': 'A demonstration of [OAS 3.0](https://www.openapis.org)',
'contact': {
'name': 'my name'
},
'license': {
'name': 'BSD 2 clause',
'url': 'https://github.com/django-json-api/django-rest-framework-json-api/blob/main/LICENSE',
}
}
schema['servers'] = [
{'url': 'http://localhost/v1', 'description': 'local docker'},
{'url': 'http://localhost:8000/v1', 'description': 'local dev'},
{'url': 'https://api.example.com/v1', 'description': 'demo server'},
{'url': '{serverURL}', 'description': 'provide your server URL',
'variables': {'serverURL': {'default': 'http://localhost:8000/v1'}}}
]
return schemaSee DRF documentation for generateschema
To generate a static OAS schema document, using the generateschema management command, you must override DRF's default generator_class with the DJA-specific version:
$ ./manage.py generateschema --generator_class rest_framework_json_api.schemas.openapi.SchemaGenerator
You can then use any number of OAS tools such as swagger-ui-watcher to render the schema:
$ swagger-ui-watcher myschema.yaml
Note: Swagger-ui-watcher will complain that "DELETE operations cannot have a requestBody" but it will still work. This error in the OAS specification will be fixed when OAS 3.1.0 is published.
(swagger-ui will work silently.)
See DRF documentation for a Dynamic Schema.
from rest_framework.schemas import get_schema_view
urlpatterns = [
...
path('openapi', get_schema_view(
title="Example API",
description="API for all things …",
version="1.0.0",
generator_class=MySchemaGenerator,
), name='openapi-schema'),
path('swagger-ui/', TemplateView.as_view(
template_name='swagger-ui.html',
extra_context={'schema_url': 'openapi-schema'}
), name='swagger-ui'),
...
]Following the example of Django REST framework we also support, encourage and strongly favor the creation of Third Party Packages to encapsulate new behavior rather than adding additional functionality directly to Django REST framework JSON:API especially when it involves adding new dependencies.
We aim to make creating third party packages as easy as possible, whilst keeping a simple and well maintained core API. By promoting third party packages we ensure that the responsibility for a package remains with its author. If a package proves suitably popular it can always be considered for inclusion into the DJA core.
To submit new content, open an issue or create a pull request.
- drf-yasg-json-api - Automated generation of Swagger/OpenAPI 2.0 from Django REST framework JSON:API endpoints.
- drf-spectacular-json-api - OpenAPI 3 schema generator for Django REST framework JSON:API based on drf-spectacular.