Django Rest Framework provides some incredible tools for serializing data, but sometimes you need to combine many serializers and/or models into a single API call. drf-multiple-model is an app designed to do just that.
Install the package from pip:
pip install django-rest-multiple-models
Make sure to add 'drf_multiple_model' to your INSTALLED_APPS:
INSTALLED_APPS = (
....
'drf_multiple_model',
)
Then simply import the view into any views.py in which you'd want to use it:
from drf_multiple_model.views import MultipleModelAPIView
Note: This package is built on top of Django Rest Framework's generic views and serializers, so it presupposes that Django Rest Framework is installed and added to your project as well.
drf-multiple-model comes with the MultipleModelAPIView generic class-based-view for serializing multiple models. MultipleModelAPIView requires a queryList attribute, which is a list or tutple of queryset/serializer pairs (in that order). For example, let's say you have the following models and serializers:
# Models
class Play(models.Model):
genre = models.CharField(max_length=100)
title = models.CharField(max_length=200)
pages = models.IntegerField()
class Poem(models.Model):
title = models.CharField(max_length=200)
style = models.CharField(max_length=100)
lines = models.IntegerField()
stanzas = models.IntegerField()
# Serializers
class PlaySerializer(serializers.ModelSerializer):
class Meta:
model = Play
fields = ('genre','title','pages')
class PoemSerializer(serializers.ModelSerializer):
class Meta:
model = Poem
fields = ('title','stanzas')
Then you might use the MultipleModelAPIView as follows:
from drf_multiple_model.views import MultipleModelAPIView
class TextAPIView(MultipleModelAPIView):
queryList = [
(Play.objects.all(),PlaySerializer),
(Poem.objects.filter(style='Sonnet'),PoemSerializer),
....
]
which would return:
[
{
'play' : [
{'genre': 'Comedy', 'title': "A Midsummer Night's Dream", 'pages': 350},
{'genre': 'Tragedy', 'title': "Romeo and Juliet", 'pages': 300},
....
],
},
{
'poem' : [
{'title': 'Shall I compare thee to a summer's day?', 'stanzas': 1},
{'title': 'As a decrepit father takes delight', 'stanzas': 1},
....
],
}
]
By default, MultipleModelAPIView uses the model name as a label. If you want to use a custome label, you can add a third attribute, a string, to the queryList tuples, like so:
from drf_multiple_model.views import MultipleModelAPIView
class TextAPIView(MultipleModelAPIView):
queryList = [
(Play.objects.all(),PlaySerializer,'plays'),
(Poem.objects.filter(style='Sonnet'),PoemSerializer,'sonnets'),
....
]
which would return:
[
{
'plays': [
{'genre': 'Comedy', 'title': "A Midsummer Night's Dream", 'pages': 350},
{'genre': 'Tragedy', 'title': "Romeo and Juliet", 'pages': 300},
....
]
},
{
'sonnets':[
{'title': 'Shall I compare thee to a summer's day?', 'stanzas': 1},
{'title': 'As a decrepit father takes delight', 'stanzas': 1},
....
],
}
]
Add the attribute flat = True to return a single JSON array with all of the objects mixed together. For example:
class TextAPIView(MultipleModelAPIView):
flat = True
queryList = [
(Play.objects.all(),PlaySerializer,'plays'),
(Poem.objects.filter(style='Sonnet'),PoemSerializer,'sonnets'),
....
]
would return:
[
{'genre': 'Comedy', 'title': "A Midsummer Night's Dream", 'pages': 350},
{'genre': 'Tragedy', 'title': "Romeo and Juliet", 'pages': 300},
....
{'title': 'Shall I compare thee to a summer's day?', 'stanzas': 1},
{'title': 'As a decrepit father takes delight', 'stanzas': 1},
....
]
When using flat=True, by default the objects will be arranged by the order in which the querysets were listed in your queryList attribute. However, you can specify a different ordering by adding the sorting_field to your view:
class TextAPIView(MultipleModelAPIView):
flat = True
sorting_field = 'title'
queryList = [
(Play.objects.all(),PlaySerializer,'plays'),
(Poem.objects.filter(style='Sonnet'),PoemSerializer,'sonnets'),
....
]
would return:
[
{'genre': 'Comedy', 'title': "A Midsummer Night's Dream", 'pages': 350},
{'title': 'As a decrepit father takes delight', 'stanzas': 1},
{'genre': 'Tragedy', 'title': "Romeo and Juliet", 'pages': 300},
{'title': 'Shall I compare thee to a summer's day?', 'stanzas': 1},
....
]
As with django field ordering, add '-' to the beginning of the field to enable reverse sorting. Setting sorting_field='-title' would sort the title fields in descending order.
WARNING: the field chosen for ordering must be shared by all models/serializers in your queryList. Any attempt to sort objects along non_shared fields will throw a KeyError.
If no label is explicitly specified in your queryList, MultipleModelAPIView will use the model from each queryset a label. If you don't want any extra labeling and just want your data as is, set add_model_type = False:
class TextAPIView(MultipleModelAPIView):
add_model_type = False
queryList = [
(Play.objects.all(),PlaySerializer,'plays'),
(Poem.objects.filter(style='Sonnet'),PoemSerializer,'sonnets'),
....
]
would return:
[
[
{'genre': 'Comedy', 'title': "A Midsummer Night's Dream", 'pages': 350},
{'genre': 'Tragedy', 'title': "Romeo and Juliet", 'pages': 300},
....
],
[
{'title': 'Shall I compare thee to a summer's day?', 'stanzas': 1},
{'title': 'As a decrepit father takes delight', 'stanzas': 1},
....
]
]
This works with flat = True set as well -- the 'type':'myModel' won't be appended to each data point in that case. Note: adding a custom label to your queryList elements will always override add_model_type. However, labels are taken on an element-by-element basis, so you can add labels for some of your models/querysets, but not others.
drf-multiple-model now supports the creation of dynamic queryLists, by overwriting the get_queryList() function rather than simply specifying the queryList variable. This allows you to do things like construct queries using url kwargs, etc:
class DynamicQueryView(MultipleModelAPIView):
def get_queryList(self):
title = self.kwargs['play'].replace('-',' ')
queryList = ((Play.objects.filter(title=title),PlaySerializer),
(Poem.objects.filter(style="Sonnet"),PoemSerializer))
return queryList
would return:
[
{ 'play': [
{'title':'Julius Caesar','genre':'Tragedy','year':1623},
]
},
{ 'poem': [
{'title':"Shall I compare thee to a summer's day?",'style':'Sonnet'},
{'title':"As a decrepit father takes delight",'style':'Sonnet'}
]}
]
If (and only if) flat = True on your view, drf-multiple-model supports some of Django Rest Framework's built-in pagination classes, including PageNumberPagination and LimitOffsetPagination. Implementatation might look like this:
class BasicPagination(pagination.PageNumberPagination):
page_size = 5
page_size_query_param = 'page_size'
max_page_size = 10
class PageNumberPaginationView(MultipleModelAPIView):
queryList = ((Play.objects.all(),PlaySerializer),
(Poem.objects.filter(style="Sonnet"),PoemSerializer))
flat = True
pagination_class = BasicPagination
which would return:
{
'count': 6,
'next': 'http://yourserver/yourUrl/?page=2',
'previous': None,
'results':
[
{'genre': 'Comedy', 'title': "A Midsummer Night's Dream", 'pages': 350},
{'genre': 'Tragedy', 'title': "Romeo and Juliet", 'pages': 300},
{'genre': 'Comedy', 'title': "The Tempest", 'pages': 250},
{'title': 'Shall I compare thee to a summer's day?', 'stanzas': 1},
{'title': 'As a decrepit father takes delight', 'stanzas': 1}
]
}
If you want to combine MultipleModelAPIView's list() function with other views, you can use the included MultipleModelMixin instead.
-
1.6 -- Incorporated and expanded on reverse sort implemented by @schweickism
-
1.5 -- Added support for Django Rest Framework's pagination classes, custom filter functions (the latter thanks to @Symmetric), and some base refactoring
-
1.3 -- Improper context passing bug fixed by @rbreu
-
1.2 -- Fixed a bug with the Browsable API when using Django Rest Framework >= 3.3
-
1.1 -- Added
get_queryList()function to support creation of dynamic queryLists -
1.0 -- initial release
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