CODEWITHSUNDEEP
pythondjangodjango-rest-framework
Stas Mercer
Stas Mercer

Reputation: 89

How to filter objects by slug instead id

I have an Event model, serializer, viewset, and a Tag model, serializer, viewset. I want filter Events by tags_name. But it's only possible to filter it by tag_id

In tag serializer I've set lookup_field in TagSerializer. Option when I 'filter_field = (tags__name)' is not appropriate, because last GET parameter change previous 

class Event(models.Model):


tags = models.ManyToManyField('Tag')

...


class Meta:
    ordering = ['name']

def __str__(self):
    return self.name


class Tag(models.Model):
  name = models.CharField(unique=True, max_length=50)

  def __str__(self):
      return self.name

  def __unicode__(self):
      return '%s'% (self.name)



class EventSerializer(serializers.ModelSerializer):
  from accounts.api.serializers import ShortUserSerializer
  tags = serializers.SlugRelatedField(
      many=True,
      queryset=Tag.objects.all(),
      slug_field='name'
  )

  members_count = serializers.SerializerMethodField()

  author = ShortUserSerializer()

  max_members = serializers.IntegerField(required=False, default=-1)

  class Meta:
      model = Event
      fields = ['id', 'name', 'description', 'time_begins', 'author', 'members_count', 'max_members', 'tags',
              'avatar', 'date_expire', 'city', 'country', 'geo']
 ...

class TagSerializer(serializers.ModelSerializer):
  class Meta:
      model = Tag
      fields = '__all__'
      lookup_field = 'name'
      extra_kwargs = {
          'url': {'lookup_field': 'name'}
      }
...

class EventViewSet(viewsets.ModelViewSet):
  queryset = Event.objects.all()
  serializer_class = EventSerializer
  http_method_names = ['get', 'patch']
  filter_backends = (filters.SearchFilter, DjangoFilterBackend,)
  search_fields = ('name', 'author__username', )
  filter_fields = ('tags')

I receive result with this:

 `localhost:8000/events/?tags=1&tags=2`

And it actually works

But I need:

 `localhost:8000/events/?tags=#fun&tags=#movie`

Upvotes: 1

Views: 1957

Answers (2)

aijogja
aijogja

Reputation: 315

What about if you try to use like this filterset_fields = ['tags__name', ]

and then access by ?tags__name=name

Upvotes: 4

Ken4scholars
Ken4scholars

Reputation: 6296

This case is not taken care of by the default filtersets generated from filter_fields. For foreign relationships it uses the idea.

Therefore, you have to define your custom filterset like this

class EventFilter(filters.FilterSet):
    tags = filters.CharFilter(field_name="tags__name", method='filter_tags')

    class Meta:
        model = Event
        fields = ['tags']

    def filter_tags(self, queryset, name, tags):
        return queryset.filter(tags__name__contains=tags.split(','))

Then you need to remove the filter_fields and add this as your filter_class in EventViewSet

class EventViewSet(viewsets.ModelViewSet):
  queryset = Event.objects.all()
  serializer_class = EventSerializer
  http_method_names = ['get', 'patch']
  filter_backends = (filters.SearchFilter, DjangoFilterBackend,)
  search_fields = ('name', 'author__username', )
  filter_class = EventFilter

Upvotes: 1

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