support read_only fields in ModelsTranslateSerializer

fix CourseSerializer thumbs related fields

courses/serializers.py

@@ -41,6 +41,27 @@ class TranslatableModelSerializerMixin(object):
                 fields += tuple(get_translation_fields(field))
         return fields
 
+    def get_extra_kwargs(self):
+        """
+        Return a dictionary mapping field names to a dictionary of
+        additional keyword arguments.
+        This class extends the original method to add tranlated fields
+        to read_only_fields if the original field is read_only
+        """
+        extra_kwargs = super().get_extra_kwargs()
+
+        read_only_fields = getattr(self.Meta, 'read_only_fields', None)
+
+        if read_only_fields is not None:
+            model_translatable_fields = get_translatable_fields_for_model(self.Meta.model)
+            for field_name in read_only_fields:
+                if field_name in model_translatable_fields:
+                    for translation_field_name in get_translation_fields(field_name):
+                        kwargs = extra_kwargs.get(translation_field_name, {})
+                        kwargs['read_only'] = True
+                        extra_kwargs[translation_field_name] = kwargs
+
+        return extra_kwargs
 
 class SimpleUserSerializer(serializers.ModelSerializer):
 
@@ -83,19 +104,24 @@ class CourseSerializer(TranslatableModelSerializerMixin, serializers.ModelSerial
 
     class Meta:
         model = Course
-        fields = ('id', 'slug', 'name', 'intro_video', 'application', 'requirement',
+        fields = ['id', 'slug', 'name', 'intro_video', 'application', 'requirement',
                   'abstract', 'structure', 'workload', 'status', 'is_public',
+                  'home_position',
+                  'thumbnail',
+                  'thumbnail_url',
                   'home_thumbnail',
-                  'home_thumbnail_url', 'home_position',
+                  'home_thumbnail_url',
                   'start_date', 'home_published', 'authors_names', 'has_started',
                   'min_percent_to_complete', 'is_user_assistant', 'is_user_coordinator',
                   'is_assistant_or_coordinator', 'professors', 'track', 'forum_id',
                   'informations', 'description', 'lang', 'course_load', 'ct_id',
                   'has_certification',
-        )
+        ]
         read_only_fields = [
             'thumbnail',
             'thumbnail_url',
+            'home_thumbnail',
+            'home_thumbnail_url',
         ]
 
     @staticmethod