Implement get_public_url for some slide types

aleksis/apps/buelleten/models/base.py

@@ -44,3 +44,6 @@ class Slide(PolymorphicModel, PureDjangoModel):
     @classmethod
     def display_supported(cls, display):
         return display.profile in cls._supported_profiles
+
+    def get_public_url(self, display=None):
+        raise NotImplementedError("Slide types need to implement the get_public_url method.")

aleksis/apps/buelleten/models/slides.py

@@ -13,6 +13,9 @@ class ForeignURLSlide(Slide):
 
     url = models.URLField(max_length=255, verbose_name=_("URL"))
 
+    def get_public_url(self, display=None):
+        return self.url
+
 
 class UploadedFileSlide(Slide):
 
@@ -43,6 +46,9 @@ class UploadedFileSlide(Slide):
         validators=[FileExtensionValidator(allowed_extensions=TYPES)],
     )
 
+    def get_public_url(self, display=None):
+        return self.file.url
+
 
 class StaticContentSlide(Slide):