Add __in filter

Adding a filter capable of handling __in queries for integer fields like
for object id.

Author: manuelnaranjo

rest_framework_filters/fields.py

@@ -0,0 +1,8 @@
+from django import forms
+
+class ArrayDecimalField(forms.DecimalField):
+    def clean(self, value):
+        out = []
+        for val in value.split(','):
+            out.append(super(ArrayDecimalField, self).clean(val))
+        return out

rest_framework_filters/filters.py

@@ -8,6 +8,7 @@
 import django_filters
 from django_filters.filters import *
 
+from . import fields
 
 def subsitute_iso8601(date_type):
     from rest_framework import ISO_8601
@@ -80,3 +81,16 @@ class TimeFilter(django_filters.DateTimeFilter):
     def __init__(self, *args, **kwargs):
         super(TimeFilter, self).__init__(*args, **kwargs)
         self.extra.update({'input_formats': TIME_INPUT_FORMATS})
+
+
+class InSetNumberFilter(NumberFilter):
+    field_class = fields.ArrayDecimalField
+
+    def filter(self, qs, value):
+        if value in ([], (), {}, None, ''):
+            return qs
+        method = qs.exclude if self.exclude else qs.filter
+        qs = method(**{self.name: value})
+        if self.distinct:
+            qs = qs.distinct()
+        return qs

rest_framework_filters/filterset.py

@@ -73,6 +73,8 @@ def fix_filter_field(self, f):
         lookup_type = f.lookup_type
         if lookup_type == 'isnull':
             return filters.BooleanFilter(name=("%s%sisnull" % (f.name, LOOKUP_SEP)))
+        if lookup_type == 'in' and type(f) in [filters.NumberFilter]:
+            return filters.InSetNumberFilter(name=("%s%sin" % (f.name, LOOKUP_SEP)))
         return f
 
     def populate_from_filterset(self, filterset, filter_, name):