neither contains or icontains is working

[ericntd-legacy]

My /api/articles/ returns 100 results.
Both /api/articles/title__contains=Hot and /api/articles/title__icontains return 100 results.
Negation is working.
Exact match is working.
My ViewSet is as follows:

import rest_framework_filters as rf_filters
from rest_framework import filters

class ArticleFilterRf(rf_filters.FilterSet):
    category = rf_filters.CharFilter(name="cat__slug")
    category_id = rf_filters.CharFilter(name="cat_id")

    class Meta:
        model = Article
        fields = ['id', 'status', 'category', 'category_id', 'deleted', 'author', 'featured', 'tags', 'title']
class ArticleViewSet(viewsets.ModelViewSet):
    """
    A viewset for viewing and editing user instances.
    """
    permission_classes = (permissions.IsAuthenticatedOrReadOnly,)
    serializer_class = ArticleSerializer
    queryset = Article.objects.all()
    filter_backends = (filters.SearchFilter, filters.DjangoFilterBackend, filters.OrderingFilter,)
    search_fields = ('title', 'tags', 'slug', 'status', 'cat__title', 'cat__slug', 'author')
    filter_class = ArticleFilterRf
    ordering_fields = ('title', 'updated')
    ordering = ('updated',)

[rpkilby]

Hi @ericntd. There is both a list syntax and dict syntax for Meta.fields. The list syntax only creates filters for the exact lookup. You should be using the dict syntax instead.

Also, make sure to use the rest_framework_filters.backends.DjangoFilterBackend backend instead of the default backend.

[jsmedmar]

does the icontains filter works for a related (ForeingKey) relationship? Wondering why it isnt working for me...

[rpkilby]

icontains does not work on a foreign key value, although it will work across relationships on a foreign field.

icontains isn't a registered lookup for FKs:
https://github.com/django/django/blob/master/django/db/models/fields/related_lookups.py

[jsmedmar]

I didn't get this part though:

although it will work across relationships on a foreign field

You are saying that it will work if I'm querying the primary key of the foreign object?

[rpkilby]

For example:

class AuthorFilter(FilterSet):
    class Meta:
        model = Author
        fields = {'username': ['icontains']}

class BookFilter(FilterSet):
    author = RelatedFilter(AuthorFilter)

   class Meta:
        model = Book

You could do /books?author__username__icontains=bob. You can traverse the author FK and do an icontains on a related field.

[jsmedmar]

Is there a way to do a symlink to a field of a RelatedFilter? something like:

class AuthorFilter(FilterSet):
    class Meta:
        model = Author
        fields = {'username': ['icontains']}

class BookFilter(FilterSet):
    username = RelatedFilter(AuthorFilter, name="username")

   class Meta:
        model = Book

I just don't want the client to know that they are actually querying a related model, that is not relevant to them.

[rpkilby]

I'm not sure if it will work, but you might be able to do...

class BookFilter(FilterSet):
    author = RelatedFilter(AuthorFilter, name="author__username")

[jsmedmar]

Ok, it didn't work... and I just realized that this solution does not work... You cannot traverse the author FK and do an icontains on a related field.

[rpkilby]

You should be able to filter on related model fields. See this as an example - it's the same idea.

The name aliasing - not so sure about that. I'll try to look into it further.

[jsmedmar]

I just get empty querysets if I don't put the exact value, for example:

>> len(list(NoteFilter({"author__username__icontains": "u"}, queryset=Note.objects.all())))
0

>>len(list(NoteFilter({"author__username__icontains": "user1"}, queryset=Note.objects.all())))
2

This is my exact setting:

settings.py

REST_FRAMEWORK = {

    'PAGE_SIZE': 10,

    'DEFAULT_PAGINATION_CLASS':
        'rest_framework.pagination.LimitOffsetPagination',

    'DEFAULT_FILTER_BACKENDS': (
        'rest_framework_filters.backends.DjangoFilterBackend',
        'rest_framework.filters.SearchFilter',
         ),

    }

filters.py

class ExtractionFilter(FilterSet):

    """Extraction Filter Class."""

    #: ``analyte`` filter field.
    analyte = AllLookupsFilter(name="analyte")

    #: ``ext_id`` filter field.
    ext_id = AllLookupsFilter(name="ext_id")

    class Meta:
        model = Extraction


class WorkflowFilter(FilterSet):

    """Workflow Filter Class."""

    #: Nested filter for ``extraction`` ForeignKey relation.
    extraction = RelatedFilter(ExtractionFilter, name="extraction")

    class Meta:
        model = Workflow

>> len(list(WorkflowFilter({"extraction__analyte__icontains": "R"}, queryset=Workflow.objects.all())))
0

>> len(list(WorkflowFilter({"extraction__analyte__icontains": "RNA"}, queryset=Workflow.objects.all())))
100

[jsmedmar]

Ok I think I found the problem...

icontains does not work with fields that have choices (analyte) but it does work on fields without choices (ext_id):

class Extraction(Model):

    analyte = models.CharField(
        verbose_name=_("Biological Material"),
        max_length=100,
        choices=CHOICES,
        null=True,
        )

    ext_id = models.CharField(
        verbose_name=_("Extraction External ID"),
        max_length=100,
        blank=True,
        default=None,
        )

Is this an expected behavior?

[rpkilby]

does not work with fields that have choices

Great catch! This if statement has been nagging me for a very long time but decided to just leave it be. The problem is that the value being filtered won't match any of the choices, so it won't validate and returns 0 results. I've submitted a PR (carltongibson/django-filter#447) to only create choice filters for exact lookups (which was probably the original intent anyway).

The following should get around this:

class FilterSet(filters.FilterSet):

    @classmethod
    def filter_for_lookup(cls, f, lookup_type):
        # copy field and remove choices to bypass default behavior
        # See: https://github.com/carltongibson/django-filter/issues/447
        if f.choices and lookup_type != 'exact':
            f = deepcopy(f)
            f.choices = None

        return super(FilterSet, cls).filter_for_lookup(f, lookup_type)

[jsmedmar]

@rpkilby hey! thank you very much, so I saw that django-filters merged your pull request. Thats great. I think I'll create a new "issue" for the field aliasing, I think that would be a nice feature for django-rest-framework-filters