How can I create a partial search filter in Django REST framework?

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I'm working with the Django REST framework library and I am trying to make a filter that can filter by first_name, last_name, or by both of them. This is my ContactViewSet.py:

class ContactViewSet(viewsets.ModelViewSet):
    queryset = Contact.objects.all()
    serializer_class = ContactSerializer
    filter_backends = (DjangoFilterBackend, )
    filter_fields = ('first_name', 'last_name')
    lookup_field = 'idContact'

My DRF's settings.py:

REST_FRAMEWORK = {
    'DEFAULT_FILTER_BACKENDS': ('django_filters.rest_framework.DjangoFilterBackend',),
}

My current request URL looks like:

http://localhost:8000/api/v1/contacts/?first_name=Clair&last_name=Test

But I'm looking for something like this:

http://localhost:8000/api/v1/contacts/?first_name=Cl**&last_name=Tes**
django-rest-swagger django-rest-framework django python
5 Answers

What I do, is write custom FilterBackend. Something like this:

# views.py
from rest_framework import filters

class ObjektFilterBackend(filters.BaseFilterBackend):
    allowed_fields = ['objekt', 'naziv', 'kategorija', 'zadnja_sprememba']

    def filter_queryset(self, request, queryset, view):
        flt = {}
        for param in request.query_params:
            for fld in self.allowed_fields:
                if param.startswith(fld):
                    flt[param] = request.query_params[param]

        return queryset.filter(**flt)


class ObjektiViewSet(mixins.ListModelMixin,
                 mixins.RetrieveModelMixin,
                 viewsets.GenericViewSet):
    authentication_classes = (
        authentication.TokenAuthentication,
        authentication.SessionAuthentication)
    permission_classes = (IsAuthenticated,)
    queryset = models.Objekt.objects.all()
    serializer_class = serializers.ObjektSerializer
    filter_backends = (ObjektFilterBackend, ObjektOrderBackend,)
    ....

Besides basic filtering (fieldname=value pairs) I can use any Django queryset Field Lookups (__gt, __gte, __startswith,...) in my URLs like this:

http://localhost:8000/api/v2/objekti/?naziv__startswith=Apartma&zadnja_sprememba__gte=2018-01-01

And ObjektFilterBackend class could be easily adapted to support searching by pattern.

Just a little warning - this approach is potentially dangerous, because it allows end user to filter also by foreign key field. Something like this also works:

http://localhost:8000/api/v2/objekti/?kategorija__naziv__icontains=sobe

So restrict allowed_fields carefully and not include foreign keys that could lead to related User model.

user_51724960

For fuzzy search lookups I recommend using this approach:

filters.py

from django_filters import rest_framework as filters
from django.db.models import Q
from . import models

def filter_name(queryset, name, value):
    """
    Split the filter value into separate search terms and construct a set of queries from this. The set of queries
    includes an icontains lookup for the lookup fields for each of the search terms. The set of queries is then joined
    with the OR operator.
    """
    lookups = [name + '__icontains', ]

    or_queries = []

    search_terms = value.split()

    for search_term in search_terms:
        or_queries += [Q(**{lookup: search_term}) for lookup in lookups]

    return queryset.filter(reduce(operator.or_, or_queries))


class ContactFilter(filters.FilterSet):
    first_name = filters.CharFilter(method=filter_name, name='first_name')
    last_name = filters.CharFilter(method=filter_name, name='last_name')

    class Meta:
        model = models.Contact
        fields = [
            'first_name',
            'last_name',
        ]

api.py

class ContactViewSet(viewsets.ModelViewSet):
    queryset = Contact.objects.all()
    serializer_class = ContactSerializer
    filter_class = ContactFilter
    ...
user_35204040
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