feat: add TypedFilter which allow to explicitly give a filter input GraphQL type (#1142)

Co-authored-by: Thomas Leonard <thomas@loftorbital.com>

docs/filtering.rst

@@ -271,3 +271,41 @@ with this set up, you can now filter events by tags:
         name
       }
     }
+
+
+`TypedFilter`
+-------------
+
+Sometimes the automatic detection of the filter input type is not satisfactory for what you are trying to achieve.
+You can then explicitly specify the input type you want for your filter by using a `TypedFilter`:
+
+.. code:: python
+
+    from django.db import models
+    from django_filters import FilterSet, OrderingFilter
+    import graphene
+    from graphene_django.filter import TypedFilter
+
+    class Event(models.Model):
+        name = models.CharField(max_length=50)
+
+    class EventFilterSet(FilterSet):
+        class Meta:
+            model = Event
+            fields = {
+                "name": ["exact", "contains"],
+            }
+
+        only_first = TypedFilter(input_type=graphene.Boolean, method="only_first_filter")
+
+        def only_first_filter(self, queryset, _name, value):
+            if value:
+                return queryset[:1]
+            else:
+                return queryset
+
+    class EventType(DjangoObjectType):
+        class Meta:
+            model = Event
+            interfaces = (Node,)
+            filterset_class = EventFilterSet

graphene_django/filter/__init__.py

@@ -15,6 +15,7 @@ else:
         GlobalIDMultipleChoiceFilter,
         ListFilter,
         RangeFilter,
+        TypedFilter,
     )
 
     __all__ = [
@@ -24,4 +25,5 @@ else:
         "ArrayFilter",
         "ListFilter",
         "RangeFilter",
+        "TypedFilter",
     ]

graphene_django/filter/filters.py

@@ -1,101 +0,0 @@
-from django.core.exceptions import ValidationError
-from django.forms import Field
-
-from django_filters import Filter, MultipleChoiceFilter
-from django_filters.constants import EMPTY_VALUES
-
-from graphql_relay.node.node import from_global_id
-
-from ..forms import GlobalIDFormField, GlobalIDMultipleChoiceField
-
-
-class GlobalIDFilter(Filter):
-    """
-    Filter for Relay global ID.
-    """
-
-    field_class = GlobalIDFormField
-
-    def filter(self, qs, value):
-        """ Convert the filter value to a primary key before filtering """
-        _id = None
-        if value is not None:
-            _, _id = from_global_id(value)
-        return super(GlobalIDFilter, self).filter(qs, _id)
-
-
-class GlobalIDMultipleChoiceFilter(MultipleChoiceFilter):
-    field_class = GlobalIDMultipleChoiceField
-
-    def filter(self, qs, value):
-        gids = [from_global_id(v)[1] for v in value]
-        return super(GlobalIDMultipleChoiceFilter, self).filter(qs, gids)
-
-
-class ListFilter(Filter):
-    """
-    Filter that takes a list of value as input.
-    It is for example used for `__in` filters.
-    """
-
-    def filter(self, qs, value):
-        """
-        Override the default filter class to check first whether the list is
-        empty or not.
-        This needs to be done as in this case we expect to get an empty output
-        (if not an exclude filter) but django_filter consider an empty list
-        to be an empty input value (see `EMPTY_VALUES`) meaning that
-        the filter does not need to be applied (hence returning the original
-        queryset).
-        """
-        if value is not None and len(value) == 0:
-            if self.exclude:
-                return qs
-            else:
-                return qs.none()
-        else:
-            return super(ListFilter, self).filter(qs, value)
-
-
-def validate_range(value):
-    """
-    Validator for range filter input: the list of value must be of length 2.
-    Note that validators are only run if the value is not empty.
-    """
-    if len(value) != 2:
-        raise ValidationError(
-            "Invalid range specified: it needs to contain 2 values.", code="invalid"
-        )
-
-
-class RangeField(Field):
-    default_validators = [validate_range]
-    empty_values = [None]
-
-
-class RangeFilter(Filter):
-    field_class = RangeField
-
-
-class ArrayFilter(Filter):
-    """
-    Filter made for PostgreSQL ArrayField.
-    """
-
-    def filter(self, qs, value):
-        """
-        Override the default filter class to check first whether the list is
-        empty or not.
-        This needs to be done as in this case we expect to get the filter applied with
-        an empty list since it's a valid value but django_filter consider an empty list
-        to be an empty input value (see `EMPTY_VALUES`) meaning that
-        the filter does not need to be applied (hence returning the original
-        queryset).
-        """
-        if value in EMPTY_VALUES and value != []:
-            return qs
-        if self.distinct:
-            qs = qs.distinct()
-        lookup = "%s__%s" % (self.field_name, self.lookup_expr)
-        qs = self.get_method(qs)(**{lookup: value})
-        return qs

graphene_django/filter/filters/__init__.py

@@ -0,0 +1,25 @@
+import warnings
+from ...utils import DJANGO_FILTER_INSTALLED
+
+if not DJANGO_FILTER_INSTALLED:
+    warnings.warn(
+        "Use of django filtering requires the django-filter package "
+        "be installed. You can do so using `pip install django-filter`",
+        ImportWarning,
+    )
+else:
+    from .array_filter import ArrayFilter
+    from .global_id_filter import GlobalIDFilter, GlobalIDMultipleChoiceFilter
+    from .list_filter import ListFilter
+    from .range_filter import RangeFilter
+    from .typed_filter import TypedFilter
+
+    __all__ = [
+        "DjangoFilterConnectionField",
+        "GlobalIDFilter",
+        "GlobalIDMultipleChoiceFilter",
+        "ArrayFilter",
+        "ListFilter",
+        "RangeFilter",
+        "TypedFilter",
+    ]

graphene_django/filter/filters/array_filter.py

@@ -0,0 +1,27 @@
+from django_filters.constants import EMPTY_VALUES
+
+from .typed_filter import TypedFilter
+
+
+class ArrayFilter(TypedFilter):
+    """
+    Filter made for PostgreSQL ArrayField.
+    """
+
+    def filter(self, qs, value):
+        """
+        Override the default filter class to check first whether the list is
+        empty or not.
+        This needs to be done as in this case we expect to get the filter applied with
+        an empty list since it's a valid value but django_filter consider an empty list
+        to be an empty input value (see `EMPTY_VALUES`) meaning that
+        the filter does not need to be applied (hence returning the original
+        queryset).
+        """
+        if value in EMPTY_VALUES and value != []:
+            return qs
+        if self.distinct:
+            qs = qs.distinct()
+        lookup = "%s__%s" % (self.field_name, self.lookup_expr)
+        qs = self.get_method(qs)(**{lookup: value})
+        return qs

graphene_django/filter/filters/global_id_filter.py

@@ -0,0 +1,28 @@
+from django_filters import Filter, MultipleChoiceFilter
+
+from graphql_relay.node.node import from_global_id
+
+from ...forms import GlobalIDFormField, GlobalIDMultipleChoiceField
+
+
+class GlobalIDFilter(Filter):
+    """
+    Filter for Relay global ID.
+    """
+
+    field_class = GlobalIDFormField
+
+    def filter(self, qs, value):
+        """ Convert the filter value to a primary key before filtering """
+        _id = None
+        if value is not None:
+            _, _id = from_global_id(value)
+        return super(GlobalIDFilter, self).filter(qs, _id)
+
+
+class GlobalIDMultipleChoiceFilter(MultipleChoiceFilter):
+    field_class = GlobalIDMultipleChoiceField
+
+    def filter(self, qs, value):
+        gids = [from_global_id(v)[1] for v in value]
+        return super(GlobalIDMultipleChoiceFilter, self).filter(qs, gids)

graphene_django/filter/filters/list_filter.py

@@ -0,0 +1,26 @@
+from .typed_filter import TypedFilter
+
+
+class ListFilter(TypedFilter):
+    """
+    Filter that takes a list of value as input.
+    It is for example used for `__in` filters.
+    """
+
+    def filter(self, qs, value):
+        """
+        Override the default filter class to check first whether the list is
+        empty or not.
+        This needs to be done as in this case we expect to get an empty output
+        (if not an exclude filter) but django_filter consider an empty list
+        to be an empty input value (see `EMPTY_VALUES`) meaning that
+        the filter does not need to be applied (hence returning the original
+        queryset).
+        """
+        if value is not None and len(value) == 0:
+            if self.exclude:
+                return qs
+            else:
+                return qs.none()
+        else:
+            return super(ListFilter, self).filter(qs, value)

graphene_django/filter/filters/range_filter.py

@@ -0,0 +1,24 @@
+from django.core.exceptions import ValidationError
+from django.forms import Field
+
+from .typed_filter import TypedFilter
+
+
+def validate_range(value):
+    """
+    Validator for range filter input: the list of value must be of length 2.
+    Note that validators are only run if the value is not empty.
+    """
+    if len(value) != 2:
+        raise ValidationError(
+            "Invalid range specified: it needs to contain 2 values.", code="invalid"
+        )
+
+
+class RangeField(Field):
+    default_validators = [validate_range]
+    empty_values = [None]
+
+
+class RangeFilter(TypedFilter):
+    field_class = RangeField

graphene_django/filter/filters/typed_filter.py

@@ -0,0 +1,27 @@
+from django_filters import Filter
+
+from graphene.types.utils import get_type
+
+
+class TypedFilter(Filter):
+    """
+    Filter class for which the input GraphQL type can explicitly be provided.
+    If it is not provided, when building the schema, it will try to guess
+    it from the field.
+    """
+
+    def __init__(self, input_type=None, *args, **kwargs):
+        self._input_type = input_type
+        super(TypedFilter, self).__init__(*args, **kwargs)
+
+    @property
+    def input_type(self):
+        input_type = get_type(self._input_type)
+        if input_type is not None:
+            if not callable(getattr(input_type, "get_type", None)):
+                raise ValueError(
+                    "Wrong `input_type` for {}: it only accepts graphene types, got {}".format(
+                        self.__class__.__name__, input_type
+                    )
+                )
+        return input_type

graphene_django/filter/tests/test_typed_filter.py

@@ -0,0 +1,156 @@
+import pytest
+
+from django_filters import FilterSet
+
+import graphene
+from graphene.relay import Node
+
+from graphene_django import DjangoObjectType
+from graphene_django.tests.models import Article, Reporter
+from graphene_django.utils import DJANGO_FILTER_INSTALLED
+
+pytestmark = []
+
+if DJANGO_FILTER_INSTALLED:
+    from graphene_django.filter import (
+        DjangoFilterConnectionField,
+        TypedFilter,
+        ListFilter,
+    )
+else:
+    pytestmark.append(
+        pytest.mark.skipif(
+            True, reason="django_filters not installed or not compatible"
+        )
+    )
+
+
+@pytest.fixture
+def schema():
+    class ArticleFilterSet(FilterSet):
+        class Meta:
+            model = Article
+            fields = {
+                "lang": ["exact", "in"],
+            }
+
+        lang__contains = TypedFilter(
+            field_name="lang", lookup_expr="icontains", input_type=graphene.String
+        )
+        lang__in_str = ListFilter(
+            field_name="lang",
+            lookup_expr="in",
+            input_type=graphene.List(graphene.String),
+        )
+        first_n = TypedFilter(input_type=graphene.Int, method="first_n_filter")
+        only_first = TypedFilter(
+            input_type=graphene.Boolean, method="only_first_filter"
+        )
+
+        def first_n_filter(self, queryset, _name, value):
+            return queryset[:value]
+
+        def only_first_filter(self, queryset, _name, value):
+            if value:
+                return queryset[:1]
+            else:
+                return queryset
+
+    class ArticleType(DjangoObjectType):
+        class Meta:
+            model = Article
+            interfaces = (Node,)
+            filterset_class = ArticleFilterSet
+
+    class Query(graphene.ObjectType):
+        articles = DjangoFilterConnectionField(ArticleType)
+
+    schema = graphene.Schema(query=Query)
+    return schema
+
+
+def test_typed_filter_schema(schema):
+    """
+    Check that the type provided in the filter is reflected in the schema.
+    """
+
+    schema_str = str(schema)
+
+    filters = {
+        "offset": "Int",
+        "before": "String",
+        "after": "String",
+        "first": "Int",
+        "last": "Int",
+        "lang": "ArticleLang",
+        "lang_In": "[ArticleLang]",
+        "lang_Contains": "String",
+        "lang_InStr": "[String]",
+        "firstN": "Int",
+        "onlyFirst": "Boolean",
+    }
+
+    all_articles_filters = (
+        schema_str.split("  articles(")[1]
+        .split("): ArticleTypeConnection\n")[0]
+        .split(", ")
+    )
+
+    for filter_field, gql_type in filters.items():
+        assert "{}: {}".format(filter_field, gql_type) in all_articles_filters
+
+
+def test_typed_filters_work(schema):
+    reporter = Reporter.objects.create(first_name="John", last_name="Doe", email="")
+    Article.objects.create(
+        headline="A", reporter=reporter, editor=reporter, lang="es",
+    )
+    Article.objects.create(
+        headline="B", reporter=reporter, editor=reporter, lang="es",
+    )
+    Article.objects.create(
+        headline="C", reporter=reporter, editor=reporter, lang="en",
+    )
+
+    query = "query { articles (lang_In: [ES]) { edges { node { headline } } } }"
+
+    result = schema.execute(query)
+    assert not result.errors
+    assert result.data["articles"]["edges"] == [
+        {"node": {"headline": "A"}},
+        {"node": {"headline": "B"}},
+    ]
+
+    query = 'query { articles (lang_InStr: ["es"]) { edges { node { headline } } } }'
+
+    result = schema.execute(query)
+    assert not result.errors
+    assert result.data["articles"]["edges"] == [
+        {"node": {"headline": "A"}},
+        {"node": {"headline": "B"}},
+    ]
+
+    query = 'query { articles (lang_Contains: "n") { edges { node { headline } } } }'
+
+    result = schema.execute(query)
+    assert not result.errors
+    assert result.data["articles"]["edges"] == [
+        {"node": {"headline": "C"}},
+    ]
+
+    query = "query { articles (firstN: 2) { edges { node { headline } } } }"
+
+    result = schema.execute(query)
+    assert not result.errors
+    assert result.data["articles"]["edges"] == [
+        {"node": {"headline": "A"}},
+        {"node": {"headline": "B"}},
+    ]
+
+    query = "query { articles (onlyFirst: true) { edges { node { headline } } } }"
+
+    result = schema.execute(query)
+    assert not result.errors
+    assert result.data["articles"]["edges"] == [
+        {"node": {"headline": "A"}},
+    ]

graphene_django/filter/utils.py

@@ -8,7 +8,7 @@ from django_filters.utils import get_model_field, get_field_parts
 from django_filters.filters import Filter, BaseCSVFilter
 
 from .filterset import custom_filterset_factory, setup_filterset
-from .filters import ArrayFilter, ListFilter, RangeFilter
+from .filters import ArrayFilter, ListFilter, RangeFilter, TypedFilter
 from ..forms import GlobalIDFormField, GlobalIDMultipleChoiceField
 
 
@@ -44,10 +44,14 @@ def get_filtering_args_from_filterset(filterset_class, type):
         form_field = None
 
         if (
-            name not in filterset_class.declared_filters
+            isinstance(filter_field, TypedFilter)
-            or isinstance(filter_field, ListFilter)
+            and filter_field.input_type is not None
-            or isinstance(filter_field, RangeFilter)
+        ):
-            or isinstance(filter_field, ArrayFilter)
+            # First check if the filter input type has been explicitely given
+            field_type = filter_field.input_type
+        else:
+            if name not in filterset_class.declared_filters or isinstance(
+                filter_field, TypedFilter
             ):
                 # Get the filter field for filters that are no explicitly declared.
                 if filter_type == "isnull":
@@ -85,19 +89,17 @@ def get_filtering_args_from_filterset(filterset_class, type):
                 #  - it's an explicitly declared filters
                 #  - we did not manage to get the type from the model type
                 form_field = form_field or filter_field.field
-            field_type = convert_form_field(form_field)
+                field_type = convert_form_field(form_field).get_type()
 
             if isinstance(filter_field, ListFilter) or isinstance(
                 filter_field, RangeFilter
             ):
                 # Replace InFilter/RangeFilter filters (`in`, `range`) argument type to be a list of
                 # the same type as the field. See comments in `replace_csv_filters` method for more details.
-            field_type = graphene.List(field_type.get_type())
+                field_type = graphene.List(field_type)
 
         args[name] = graphene.Argument(
-            type=field_type.get_type(),
+            type=field_type, description=filter_field.label, required=required,
-            description=filter_field.label,
-            required=required,
         )
 
     return args