Add option to allow fallback language in post/category URLs (nephila#572)

Add setting BLOG_USE_FALLBACK_LANGUAGE_IN_URL. If enabled, and a blog
post/category doesn't exist in the current language, prefer displaying the URL
in the fallback language.

Author: jasujm

HISTORY.rst

@@ -4,6 +4,12 @@
 History
 =======
 
+**********
+Unreleased
+**********
+
+* Add BLOG_USE_FALLBACK_LANGUAGE_IN_URL setting
+
 *******************
 1.1.1 (2020-05-15)
 *******************

djangocms_blog/models.py

@@ -51,6 +51,23 @@ class KnockerModel:
         pass
 
 
+def _get_language(instance, language):
+    available_languages = instance.get_available_languages()
+    if language and language in available_languages:
+        return language
+    language = get_language()
+    if language and language in available_languages:
+        return language
+    language = instance.get_current_language()
+    if language and language in available_languages:
+        return language
+    if get_setting('USE_FALLBACK_LANGUAGE_IN_URL'):
+        for fallback_language in instance.get_fallback_languages():
+            if fallback_language in available_languages:
+                return fallback_language
+    return language
+
+
 class BlogMetaMixin(ModelMeta):
 
     def get_meta_attribute(self, param):
@@ -142,10 +159,7 @@ def count_all_sites(self):
         return self.linked_posts.published(current_site=False).count()
 
     def get_absolute_url(self, lang=None):
-        if not lang or lang not in self.get_available_languages():
-            lang = get_language()
-        if not lang or lang not in self.get_available_languages():
-            lang = self.get_current_language()
+        lang = _get_language(self, lang)
         if self.has_translation(lang):
             slug = self.safe_translation_getter('slug', language_code=lang)
             return reverse(
@@ -328,10 +342,7 @@ def save_translation(self, translation, *args, **kwargs):
         super(Post, self).save_translation(translation, *args, **kwargs)
 
     def get_absolute_url(self, lang=None):
-        if not lang or lang not in self.get_available_languages():
-            lang = get_language()
-        if not lang or lang not in self.get_available_languages():
-            lang = self.get_current_language()
+        lang = _get_language(self, lang)
         with switch_language(self, lang):
             category = self.categories.first()
             kwargs = {}

djangocms_blog/settings.py

@@ -159,6 +159,8 @@ def get_setting(name):
 
         'BLOG_PLUGIN_TEMPLATE_FOLDERS': getattr(
             settings, 'BLOG_PLUGIN_TEMPLATE_FOLDERS', (('plugins', _('Default template')),)),
+        'BLOG_USE_FALLBACK_LANGUAGE_IN_URL': getattr(
+            settings, 'BLOG_USE_FALLBACK_LANGUAGE_IN_URL', False),
 
     }
     return default['BLOG_%s' % name]

docs/settings.rst

@@ -99,6 +99,7 @@ Global Settings
 * BLOG_META_TITLE_LENGTH: Maximum length for the Meta title field (default: ``70``)
 * BLOG_ABSTRACT_CKEDITOR: Configuration for the CKEditor of the abstract field (as per https://github.com/divio/djangocms-text-ckeditor/#customizing-htmlfield-editor)
 * BLOG_POST_TEXT_CKEDITOR: Configuration for the CKEditor of the post content field
+* BLOG_USE_FALLBACK_LANGUAGE_IN_URL: When displaying URL, prefer URL in the fallback language if an article or category is not available in the current language
 
 ******************
 Read-only settings

tests/test_models.py

@@ -20,6 +20,8 @@
 from django.utils.timezone import now
 from django.utils.translation import get_language, override
 from menus.menu_pool import menu_pool
+from parler.tests.utils import override_parler_settings
+from parler.utils.conf import add_default_language_settings
 from parler.utils.context import smart_override
 from taggit.models import Tag
 
@@ -978,6 +980,32 @@ def test_url_language(self):
             self.assertEqual(post.get_current_language(), 'it')
             self.assertEqual(post.get_absolute_url(), post.get_absolute_url('en'))
 
+    def test_url_language_use_fallback(self):
+        self.get_pages()
+        post = self._get_post(self._post_data[0]['en'])
+
+        PARLER_FALLBACK = {
+            1: (
+                {'code': 'en'},
+                {'code': 'it'},
+            ),
+            'default': {
+                'fallbacks': ['fr', 'en'],
+                'hide_untranslated': False,
+            }
+        }
+        PARLER_FALLBACK = add_default_language_settings(PARLER_FALLBACK)
+
+        with override_parler_settings(PARLER_LANGUAGES=PARLER_FALLBACK):
+            with override('it'):
+                post.set_current_language('it')
+                self.assertEqual(post.get_absolute_url(), post.get_absolute_url('it'))
+
+            with override_settings(BLOG_USE_FALLBACK_LANGUAGE_IN_URL=True):
+                with override('it'):
+                    post.set_current_language('it')
+                    self.assertEqual(post.get_absolute_url(), post.get_absolute_url('en'))
+
     def test_manager(self):
         self.get_pages()
         post1 = self._get_post(self._post_data[0]['en'])