Support to_field_name for related filters (#294)

Author: ferrants

rest_framework_filters/filterset.py

@@ -1,7 +1,6 @@
 import copy
 from collections import OrderedDict
 
-from django.db.models import Subquery
 from django.db.models.constants import LOOKUP_SEP
 from django_filters import filterset, rest_framework
 from django_filters.utils import get_model_field
@@ -300,9 +299,13 @@ def filter_related_filtersets(self, queryset):
             if not any(value.startswith(prefix) for value in self.data):
                 continue
 
+            field = self.filters[related_name].field
+            to_field_name = getattr(field, 'to_field_name', 'pk') or 'pk'
+
             field_name = self.filters[related_name].field_name
             lookup_expr = LOOKUP_SEP.join([field_name, 'in'])
-            subquery = Subquery(related_filterset.qs.values('pk'))
+
+            subquery = related_filterset.qs.values(to_field_name)
             queryset = queryset.filter(**{lookup_expr: subquery})
 
         return queryset

tests/test_filtering.py

@@ -4,10 +4,12 @@
 from rest_framework_filters import FilterSet, filters
 
 from .testapp.filters import (
-    CFilter, CoverFilter, NoteFilter, NoteFilterWithAlias, NoteFilterWithRelatedAlias,
-    PageFilter, PersonFilter, PostFilter, UserFilter,
+    AccountFilter, CFilter, CoverFilter, CustomerFilter, NoteFilter, NoteFilterWithAlias,
+    NoteFilterWithRelatedAlias, PageFilter, PersonFilter, PostFilter, UserFilter,
+)
+from .testapp.models import (
+    A, Account, B, C, Cover, Customer, Note, Page, Person, Post, Tag, User,
 )
-from .testapp.models import A, B, C, Cover, Note, Page, Person, Post, Tag, User
 
 
 class LocalTagFilter(FilterSet):
@@ -81,54 +83,47 @@ class RelatedFilterTests(TestCase):
 
     @classmethod
     def setUpTestData(cls):
-        #######################
-        # Create users
-        #######################
+        ########################################################################
+        # Create users #########################################################
         user1 = User.objects.create(username="user1", email="user1@example.org")
         user2 = User.objects.create(username="user2", email="user2@example.org")
 
-        #######################
-        # Create notes
-        #######################
+        ########################################################################
+        # Create notes #########################################################
         note1 = Note.objects.create(title="Test 1", content="Test content 1", author=user1)
         note2 = Note.objects.create(title="Test 2", content="Test content 2", author=user1)
         Note.objects.create(title="Hello Test 3", content="Test content 3", author=user1)
         note4 = Note.objects.create(title="Hello Test 4", content="Test content 4", author=user2)
 
-        #######################
-        # Create posts
-        #######################
+        ########################################################################
+        # Create posts #########################################################
         post1 = Post.objects.create(note=note1, content="Test content in post 1")
         Post.objects.create(note=note2, content="Test content in post 2")
         post3 = Post.objects.create(note=note4, content="Test content in post 3")
 
-        #######################
-        # Create covers
-        #######################
+        ########################################################################
+        # Create covers ########################################################
         Cover.objects.create(post=post1, comment="Cover 1")
         Cover.objects.create(post=post3, comment="Cover 2")
 
-        #######################
-        # Create pages
-        #######################
+        ########################################################################
+        # Create pages #########################################################
         Page.objects.create(title="First page", content="First first.")
         Page.objects.create(title="Second page", content="Second second.", previous_page_id=1)
         Page.objects.create(title="Third page", content="Third third.", previous_page_id=2)
         Page.objects.create(title="Fourth page", content="Fourth fourth.", previous_page_id=3)
 
-        ################################
-        # ManyToMany
-        ################################
+        ########################################################################
+        # ManyToMany ###########################################################
         t1 = Tag.objects.create(name="park")
         Tag.objects.create(name="lake")
         t3 = Tag.objects.create(name="house")
 
         post1.tags.set([t1, t3])
         post3.tags.set([t3])
 
-        ################################
-        # Recursive relations
-        ################################
+        ########################################################################
+        # Recursive relations ##################################################
         a = A.objects.create(title="A1")
         b = B.objects.create(name="B1")
         c = C.objects.create(title="C1")
@@ -146,6 +141,17 @@ def setUpTestData(cls):
         john = Person.objects.create(name="John")
         Person.objects.create(name="Mark", best_friend=john)
 
+        ########################################################################
+        # to_field relations ###################################################
+        c1 = Customer.objects.create(name='Bob Jones', ssn='111111111', dob='1990-01-01')
+        c2 = Customer.objects.create(name='Sue Jones', ssn='222222222', dob='1990-01-01')
+
+        Account.objects.create(customer=c1, type='c', name='Bank 1 checking')
+        Account.objects.create(customer=c1, type='s', name='Bank 1 savings')
+        Account.objects.create(customer=c2, type='c', name='Bank 1 checking 1')
+        Account.objects.create(customer=c2, type='c', name='Bank 1 checking 2')
+        Account.objects.create(customer=c2, type='s', name='Bank 2 savings')
+
     def test_relatedfilter(self):
         # Test that the default exact filter works
         GET = {'author': User.objects.get(username='user2').pk}
@@ -399,6 +405,17 @@ def test_empty_param_name(self):
         f = NoteFilter(GET, queryset=Note.objects.all())
         self.assertEqual(len(list(f.qs)), 1)
 
+    def test_to_field_forwards_relation(self):
+        GET = {'customer__name': 'Bob Jones'}
+        f = AccountFilter(GET)
+        self.assertEqual(len(list(f.qs)), 2)
+
+    def test_to_field_reverse_relation(self):
+        # Note: pending #99, this query should ideally return 2 distinct results
+        GET = {'accounts__type': 'c'}
+        f = CustomerFilter(GET)
+        self.assertEqual(len(list(f.qs)), 3)
+
 
 class AnnotationTests(TestCase):
     # TODO: these tests should somehow assert that the annotation method is

tests/testapp/filters.py

@@ -5,7 +5,9 @@
 from rest_framework_filters.filters import AutoFilter, RelatedFilter
 from rest_framework_filters.filterset import FilterSet
 
-from .models import A, B, Blog, C, Cover, Note, Page, Person, Post, Tag, User
+from .models import (
+    A, Account, B, Blog, C, Cover, Customer, Note, Page, Person, Post, Tag, User,
+)
 
 
 class DFUserFilter(django_filters.FilterSet):
@@ -101,9 +103,8 @@ class Meta:
         fields = []
 
 
-#############################################################
-# Aliased parameter names
-#############################################################
+################################################################################
+# Aliased parameter names ######################################################
 class UserFilterWithAlias(FilterSet):
     name = filters.CharFilter(field_name='username')
 
@@ -129,9 +130,8 @@ class Meta:
         fields = []
 
 
-#############################################################
-# Recursive filtersets
-#############################################################
+################################################################################
+# Recursive filtersets #########################################################
 class AFilter(FilterSet):
     title = filters.CharFilter(field_name='title')
     b = RelatedFilter('BFilter', field_name='b', queryset=B.objects.all())
@@ -170,3 +170,21 @@ class PersonFilter(FilterSet):
     class Meta:
         model = Person
         fields = []
+
+
+################################################################################
+# `to_field` filtersets ########################################################
+class CustomerFilter(FilterSet):
+    accounts = RelatedFilter('AccountFilter', field_name='account', queryset=Account.objects.all())
+
+    class Meta:
+        model = Customer
+        fields = ['name', 'ssn', 'dob', 'accounts']
+
+
+class AccountFilter(FilterSet):
+    customer = RelatedFilter('CustomerFilter', to_field_name='ssn', queryset=Customer.objects.all())
+
+    class Meta:
+        model = Account
+        fields = ['customer', 'type', 'name']

tests/testapp/migrations/0001_initial.py

@@ -1,4 +1,4 @@
-# Generated by Django 2.2.2 on 2019-06-05 21:58
+# Generated by Django 2.2.2 on 2019-08-14 20:04
 
 from django.conf import settings
 from django.db import migrations, models
@@ -28,6 +28,15 @@ class Migration(migrations.Migration):
                 ('name', models.CharField(max_length=100)),
             ],
         ),
+        migrations.CreateModel(
+            name='Customer',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=80)),
+                ('ssn', models.CharField(max_length=9, unique=True)),
+                ('dob', models.DateField()),
+            ],
+        ),
         migrations.CreateModel(
             name='Note',
             fields=[
@@ -101,6 +110,15 @@ class Migration(migrations.Migration):
                 ('c', models.ForeignKey(null=True, on_delete=django.db.models.deletion.CASCADE, to='testapp.C')),
             ],
         ),
+        migrations.CreateModel(
+            name='Account',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('type', models.CharField(choices=[('c', 'Checking'), ('s', 'Savings')], max_length=1)),
+                ('name', models.CharField(max_length=80)),
+                ('customer', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='testapp.Customer', to_field='ssn')),
+            ],
+        ),
         migrations.AddField(
             model_name='a',
             name='b',

tests/testapp/models.py

@@ -73,3 +73,16 @@ class Person(models.Model):
     date_joined = models.DateField(auto_now_add=True)
     time_joined = models.TimeField(auto_now_add=True)
     datetime_joined = models.DateTimeField(auto_now_add=True)
+
+
+# Models using `to_field`
+class Customer(models.Model):
+    name = models.CharField(max_length=80)
+    ssn = models.CharField(max_length=9, unique=True)
+    dob = models.DateField()
+
+
+class Account(models.Model):
+    customer = models.ForeignKey(Customer, to_field='ssn', on_delete=models.CASCADE)
+    type = models.CharField(max_length=1, choices=[('c', 'Checking'), ('s', 'Savings')])
+    name = models.CharField(max_length=80)