Make 'get_filter_name' more robust, add tests

Author: Ryan P Kilby

rest_framework_filters/filterset.py

@@ -134,6 +134,21 @@ def get_filters(self):
     def get_filter_name(cls, param):
         """
         Get the filter name for the request data parameter.
+
+        ex::
+
+            # regular attribute filters
+            name = FilterSet.get_filter_name('email')
+            assert name == 'email'
+
+            # exclusion filters
+            name = FilterSet.get_filter_name('email!')
+            assert name == 'email'
+
+            # related filters
+            name = FilterSet.get_filter_name('author__email')
+            assert name == 'author'
+
         """
         # Attempt to match against filters with lookups first. (username__endswith)
         if param in cls.base_filters:
@@ -143,11 +158,18 @@ def get_filter_name(cls, param):
         if param[-1] == '!' and param[:-1] in cls.base_filters:
             return param[:-1]
 
-        # Fallback to matching against relationships. (author__username__endswith)
-        related_param = param.split(LOOKUP_SEP, 1)[0]
-        f = cls.base_filters.get(related_param, None)
-        if isinstance(f, filters.RelatedFilter):
-            return related_param
+        # Fallback to matching against relationships. (author__username__endswith).
+        related_filters = [
+            name for name, f in six.iteritems(cls.base_filters)
+            if isinstance(f, filters.RelatedFilter)
+        ]
+
+        # preference more specific filters. eg, `note__author` over `note`.
+        for name in sorted(related_filters)[::-1]:
+            # we need to match against '__' to prevent eager matching against
+            # like names. eg, note vs note2. Exact matches are handled above.
+            if param.startswith("%s__" % name):
+                return name
 
     @classmethod
     def get_subset(cls, params):

tests/test_filterset.py

@@ -324,6 +324,84 @@ def test_nonexistent_related_field(self):
         self.assertEqual(len(list(f)), 4)
 
 
+class GetFilterNameTests(TestCase):
+
+    def test_regular_filter(self):
+        name = UserFilter.get_filter_name('email')
+        self.assertEqual('email', name)
+
+    def test_exclusion_filter(self):
+        name = UserFilter.get_filter_name('email!')
+        self.assertEqual('email', name)
+
+    def test_non_filter(self):
+        name = UserFilter.get_filter_name('foobar')
+        self.assertEqual(None, name)
+
+    def test_related_filter(self):
+        # 'exact' matches
+        name = NoteFilterWithRelated.get_filter_name('author')
+        self.assertEqual('author', name)
+
+        # related attribute filters
+        name = NoteFilterWithRelated.get_filter_name('author__email')
+        self.assertEqual('author', name)
+
+        # non-existent related filters should match, as it's the responsibility
+        # of the related filterset to handle non-existent filters
+        name = NoteFilterWithRelated.get_filter_name('author__foobar')
+        self.assertEqual('author', name)
+
+    def test_twice_removed_related_filter(self):
+        class PostFilterWithDirectAuthor(PostFilter):
+            note__author = filters.RelatedFilter(UserFilter)
+            note = filters.RelatedFilter(NoteFilterWithAll)
+
+            class Meta:
+                model = Post
+
+        name = PostFilterWithDirectAuthor.get_filter_name('note__title')
+        self.assertEqual('note', name)
+
+        # 'exact' matches, preference more specific filter name, as less specific
+        # filter may not have related access.
+        name = PostFilterWithDirectAuthor.get_filter_name('note__author')
+        self.assertEqual('note__author', name)
+
+        # related attribute filters
+        name = PostFilterWithDirectAuthor.get_filter_name('note__author__email')
+        self.assertEqual('note__author', name)
+
+        # non-existent related filters should match, as it's the responsibility
+        # of the related filterset to handle non-existent filters
+        name = PostFilterWithDirectAuthor.get_filter_name('note__author__foobar')
+        self.assertEqual('note__author', name)
+
+    def test_name_hiding(self):
+        class PostFilterWithDirectAuthor(PostFilter):
+            note__author = filters.RelatedFilter(UserFilter)
+            note = filters.RelatedFilter(NoteFilterWithAll)
+            note2 = filters.RelatedFilter(NoteFilterWithAll)
+
+            class Meta:
+                model = Post
+
+        name = PostFilterWithDirectAuthor.get_filter_name('note__author')
+        self.assertEqual('note__author', name)
+
+        name = PostFilterWithDirectAuthor.get_filter_name('note__title')
+        self.assertEqual('note', name)
+
+        name = PostFilterWithDirectAuthor.get_filter_name('note')
+        self.assertEqual('note', name)
+
+        name = PostFilterWithDirectAuthor.get_filter_name('note2')
+        self.assertEqual('note2', name)
+
+        name = PostFilterWithDirectAuthor.get_filter_name('note2__author')
+        self.assertEqual('note2', name)
+
+
 class FilterSubsetTests(TestCase):
 
     def test_get_subset(self):