Properly support formatting of link segments in related urls

CHANGELOG.md

@@ -19,6 +19,13 @@ any parts of the framework not mentioned in the documentation should generally b
 
 * Allow `get_serializer_class` to be overwritten when using related urls without defining `serializer_class` fallback
 * Preserve field names when no formatting is configured.
+* Properly support `JSON_API_FORMAT_RELATED_LINKS` setting in related urls. In case you want to use `dasherize` for formatting links make sure that your url pattern matches dashes as well like following example:
+  ```
+  url(r'^orders/(?P<pk>[^/.]+)/(?P<related_field>[-\w]+)/$',
+      OrderViewSet.as_view({'get': 'retrieve_related'}),
+      name='order-related'),
+  ```
+
 
 ### Deprecated
 

docs/usage.md

@@ -515,6 +515,11 @@ For example, with a serializer property `created_by` and with `'dasherize'` form
 
 The relationship name is formatted by the `JSON_API_FORMAT_FIELD_NAMES` setting, but the URL segments are formatted by the `JSON_API_FORMAT_RELATED_LINKS` setting.
 
+<div class="warning">
+    <strong>Note:</strong>
+    When using this setting make sure that your url pattern matches the formatted url segement.
+</div>
+
 ### Related fields
 
 #### ResourceRelatedField
@@ -702,7 +707,7 @@ All you need is just add to `urls.py`:
 url(r'^orders/(?P<pk>[^/.]+)/$',
         OrderViewSet.as_view({'get': 'retrieve'}),
         name='order-detail'),
-url(r'^orders/(?P<pk>[^/.]+)/(?P<related_field>\w+)/$',
+url(r'^orders/(?P<pk>[^/.]+)/(?P<related_field>[-\w]+)/$',
         OrderViewSet.as_view({'get': 'retrieve_related'}),
         name='order-related'),
 ```
@@ -775,7 +780,7 @@ The urlconf would need to contain a route like the following:
 
 ```python
 url(
-    regex=r'^orders/(?P<pk>[^/.]+)/relationships/(?P<related_field>[^/.]+)$',
+    regex=r'^orders/(?P<pk>[^/.]+)/relationships/(?P<related_field>[-/w]+)$',
     view=OrderRelationshipView.as_view(),
     name='order-relationships'
 )

example/tests/test_views.py

@@ -1,7 +1,7 @@
 import json
 from datetime import datetime
 
-from django.test import RequestFactory
+from django.test import RequestFactory, override_settings
 from django.utils import timezone
 from rest_framework import status
 from rest_framework.decorators import action
@@ -92,6 +92,18 @@ def test_get_blog_relationship_entry_set(self):
 
         assert response.data == expected_data
 
+    @override_settings(JSON_API_FORMAT_RELATED_LINKS="dasherize")
+    def test_get_blog_relationship_entry_set_with_formatted_link(self):
+        response = self.client.get(
+            "/blogs/{}/relationships/entry-set".format(self.blog.id)
+        )
+        expected_data = [
+            {"type": format_resource_type("Entry"), "id": str(self.first_entry.id)},
+            {"type": format_resource_type("Entry"), "id": str(self.second_entry.id)},
+        ]
+
+        assert response.data == expected_data
+
     def test_put_entry_relationship_blog_returns_405(self):
         url = "/entries/{}/relationships/blog".format(self.first_entry.id)
         response = self.client.put(url, data={})
@@ -507,6 +519,17 @@ def test_retrieve_related_None(self):
         self.assertEqual(resp.status_code, 200)
         self.assertEqual(resp.json(), {"data": None})
 
+    @override_settings(JSON_API_FORMAT_RELATED_LINKS="dasherize")
+    def test_retrieve_related_with_formatted_link(self):
+        first_entry = EntryFactory(authors=(self.author,))
+
+        kwargs = {"pk": self.author.pk, "related_field": "first-entry"}
+        url = reverse("author-related", kwargs=kwargs)
+        resp = self.client.get(url)
+
+        self.assertEqual(resp.status_code, 200)
+        self.assertEqual(resp.json()["data"]["id"], str(first_entry.id))
+
 
 class TestValidationErrorResponses(TestBase):
     def test_if_returns_error_on_empty_post(self):

example/urls_test.py

@@ -78,17 +78,17 @@
         name="entry-featured",
     ),
     re_path(
-        r"^authors/(?P<pk>[^/.]+)/(?P<related_field>\w+)/$",
+        r"^authors/(?P<pk>[^/.]+)/(?P<related_field>[-\w]+)/$",
         AuthorViewSet.as_view({"get": "retrieve_related"}),
         name="author-related",
     ),
     re_path(
-        r"^entries/(?P<pk>[^/.]+)/relationships/(?P<related_field>\w+)$",
+        r"^entries/(?P<pk>[^/.]+)/relationships/(?P<related_field>[\-\w]+)$",
         EntryRelationshipView.as_view(),
         name="entry-relationships",
     ),
     re_path(
-        r"^blogs/(?P<pk>[^/.]+)/relationships/(?P<related_field>\w+)$",
+        r"^blogs/(?P<pk>[^/.]+)/relationships/(?P<related_field>[^/.]+)$",
         BlogRelationshipView.as_view(),
         name="blog-relationships",
     ),

rest_framework_json_api/views.py

@@ -157,7 +157,7 @@ def get_related_serializer_class(self):
         parent_serializer_class = self.get_serializer_class()
 
         if "related_field" in self.kwargs:
-            field_name = self.kwargs["related_field"]
+            field_name = self.get_related_field_name()
 
             # Try get the class from related_serializers
             if hasattr(parent_serializer_class, "related_serializers"):
@@ -402,6 +402,8 @@ def get_related_instance(self):
 
     def get_related_field_name(self):
         field_name = self.kwargs["related_field"]
+        field_name = undo_format_link_segment(field_name)
+
         if field_name in self.field_name_mapping:
             return self.field_name_mapping[field_name]
         return field_name