Django-filters: multiple IDs in a single query string

Question

Using django-filters, I see various solutions for how to submit multiple arguments of the same type in a single query string, for example for multiple IDs. They all suggest using a separate field that contains a comma-separated list of values, e.g.:

http://example.com/api/cities?ids=1,2,3

Is there a general solution for using a single parameter but submitted one or more times? E.g.:

http://example.com/api/cities?id=1&id=2&id=3

I tried using MultipleChoiceFilter, but it expects actual choices to be defined whereas I want to pass arbitrary IDs (some of which may not even exist in the DB).

What do you mean with some not even exist in the db? What should happen then? — willeM_ Van Onsem
– willeM_ Van Onsem, Commented Jun 11, 2018 at 13:56
@WillemVanOnsem A standard IN lookup should be used. If you request id=1&id=2 and resource with ID 2 does not exist, only the first one would be returned in the list of results. If neither exist, an empty list would be returned. — mart1n
– mart1n, Commented Jun 11, 2018 at 14:04
Does this answer your question? How do you use the django-filter package with a list of parameters? — Josh Correia
– Josh Correia, Commented Jun 30, 2021 at 18:00

Benoit Blanchon · Accepted Answer · 2020-10-27 09:55:16Z

9

Here is a reusable solution using a custom Filter and a custom Field.

The custom Field reuses Django's MultipleChoiceField but replaces the validation functions. Instead, it validates using another Field class that we pass to the constructor.

from django.forms.fields import MultipleChoiceField

class MultipleValueField(MultipleChoiceField):
    def __init__(self, *args, field_class, **kwargs):
        self.inner_field = field_class()
        super().__init__(*args, **kwargs)

    def valid_value(self, value):
        return self.inner_field.validate(value)

    def clean(self, values):
        return values and [self.inner_field.clean(value) for value in values]

The custom Filter uses MultipleValueField and forwards the field_class argument. It also sets the default value of lookup_expr to in.

from django_filters.filters import Filter

class MultipleValueFilter(Filter):
    field_class = MultipleValueField

    def __init__(self, *args, field_class, **kwargs):
        kwargs.setdefault('lookup_expr', 'in')
        super().__init__(*args, field_class=field_class, **kwargs)

To use this filter, simply create a MultipleValueFilter with the appropriate field_class. For example, to filter City by id, we can use a IntegerField, like so:

from django.forms.fields import IntegerField

class CityFilterSet(FilterSet):
    id = MultipleValueFilter(field_class=IntegerField)
    name = filters.CharFilter(lookup_expr='icontains')

    class Meta:
        model = City
        fields = ['name']

answered Oct 27, 2020 at 9:55

Benoit Blanchon

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1 Comment

sanchaz Over a year ago

thanks for this. I've posted an improvement to allow for lookup_exprs such as iexact. stackoverflow.com/a/68162262/1321009

Sergey Telminov · Accepted Answer · 2019-08-21 07:53:40Z

7

As option

class CityFilterSet(django_filters.FilterSet):
    id = django_filters.NumberFilter(method='filter_id')

    def filter_id(self, qs, name, value):
        return qs.filter(id__in=self.request.GET.getlist('id'))

answered Aug 21, 2019 at 7:53

Sergey Telminov

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Comments

mart1n · Accepted Answer · 2018-06-12 06:47:58Z

4

Solved using a custom filter, inspired by Jerin's answer:

class ListFilter(Filter):
    def filter(self, queryset, value):
        try:
            request = self.parent.request
        except AttributeError:
            return None

        values = request.GET.getlist(self.name)
        values = {int(item) for item in values if item.isdigit()}

        return super(ListFilter, self).filter(queryset, Lookup(values, 'in'))

If the values were to be non-digit, e.g. color=blue&color=red then the isdigit() validation is of course not necessary.

answered Jun 12, 2018 at 6:47

mart1n

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1 Comment

Leogout Over a year ago

Seems weird to me that this is not default behavior in django-filters yet... It is a common use case.

JPG · Accepted Answer · 2018-06-12 06:19:03Z

2

I would recommend you to use a custom filter, as below

from django_filters.filters import Filter
from rest_framework.serializers import ValidationError
from django_filters.fields import Lookup


class ListFilter(Filter):
    def filter(self, queryset, value):
        list_values = value.split(',')
        if not all(item.isdigit() for item in list_values):
            raise ValidationError('All values in %s the are not integer' % str(list_values))
        return super(ListFilter, self).filter(queryset, Lookup(list_values, 'in'))

answered Jun 12, 2018 at 6:19

JPG

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1 Comment

mart1n Over a year ago

Right, that's the solution for when you want to pass multiple values as ids=1,2,3, but I'm specifically looking for how to handle multiple arguments of the same name, so id=1&id=2&id=3.

Community · Accepted Answer · 2020-06-20 09:12:55Z

I have some problems with this solution

So I changed it a bit:

class ListFilter(Filter):
    def __init__(self, query_param, *args, **kwargs):
        super(ListFilter, self).__init__(*args, **kwargs)
        # url = /api/cities/?id=1&id=2&id=3 or /api/cities/?id=1,2,3
        # or /api/cities/?id=1&id=2&id=3?id=4,5,6
        self.query_param = query_param 
        self.lookup_expr = 'in'

    def filter(self, queryset, value):
        try:
            request = self.parent.request
        except AttributeError:
            return None

        values = set()
        query_list = request.GET.getlist(self.query_param)
        for v in query_list:
            values = values.union(set(v.split(',')))
        values = set(map(int, values))

        return super(ListFilter, self).filter(queryset, values)

class CityFilter(filterset.FilterSet):
    id = ListFilter(field_name='id', query_param='id')
    name = filters.CharFilter(field_name='name', lookup_expr='icontains')

    class Meta:
        model = City
        fields = ['name']

If you want to use custom query param name - change query_param arg.

Nathan · Accepted Answer · 2022-11-03 04:22:44Z

2

On django-filter version 22.1 we can use django_filters.AllValuesMultipleFilter().

import django_filters


class CityFilterSet(django_filters.FilterSet):
    id = django_filters.AllValuesMultipleFilter(label='id')

On browsable API it can show the current id options it can use as values.

answered Nov 3, 2022 at 4:22

Nathan

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1 Comment

Rarity Belle Over a year ago

Love it when there's a native way to do things.

sanchaz · Accepted Answer · 2021-06-28 11:07:35Z

Benoit Blanchon had imo the best

But I've tried to improve on it to allow for more types of lookup_expr's. See his answer for the complete code snippets.

from django.db.models import Q

class MultipleValueFilter(Filter):
    field_class = MultipleValueField

    def __init__(self, *args, field_class, **kwargs):
        kwargs.setdefault('lookup_expr', 'in')
        super().__init__(*args, field_class=field_class, **kwargs)

    def filter(self, qs, value):
        # if it's not a list then let the parent deal with it
        if self.lookup_expr == 'in' or not isinstance(value, list):
            return super().filter(qs, value)

        # empty list
        if not value:
            return qs
        if self.distinct:
            qs = qs.distinct()

        lookup = '%s__%s' % (self.field_name, self.lookup_expr)
        filters = Q()
        for v in value:
            filters |= Q(**{lookup: v})
        qs = self.get_method(qs)(filters)
        return qs

With this change you can now use iexact for example. You can also use gte, etc, but those will probably not make much sense.

Savai Maheshwari · Accepted Answer · 2018-06-14 07:34:39Z

-3

http://example.com/api/cities?ids=1,2,3

get_ids=1,2,3
id_list = list(get_ides]
Mdele_name.objects.filter(id__in= id_list)

answered Jun 14, 2018 at 7:34

Savai Maheshwari

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