Simplify some expressions

boards/models/tag.py

@@ -11,9 +11,11 from boards.models.base import Viewable
 from boards.models.thread import STATUS_ACTIVE, STATUS_BUMPLIMIT, STATUS_ARCHIVE
 from boards.utils import cached_result
 
+
 __author__ = 'neko259'
 
 
+TAG_DELIMITER = ', '
 RELATED_TAGS_COUNT = 5
 DEFAULT_LOCALE = 'default'
 
@@ -42,30 +44,18 class TagAlias(models.Model, Viewable):
 
 
 class TagManager(models.Manager):
-    def get_not_empty_tags(self):
-        """
-        Gets tags that have non-archived threads.
-        """
-
-        return self.annotate(num_threads=Count('thread_tags'))\
-                .filter(num_threads__gt=0)\
-                .filter(aliases__in=TagAlias.objects.filter_localized())\
-                .order_by('aliases__name')
-
     def get_tag_url_list(self, tags: list) -> str:
         """
         Gets a comma-separated list of tag links.
         """
 
-        return ', '.join([tag.get_view() for tag in tags])
+        return TAG_DELIMITER.join([tag.get_view() for tag in tags])
 
     def get_by_alias(self, alias):
-        tag = None
-        aliases = TagAlias.objects.filter(name=alias).all()
-        if aliases:
-            tag = aliases[0].parent
-
-        return tag
+        try:
+            return self.get(aliases__name__in=alias)
+        except Tag.DoesNotExist:
+            pass
 
     def get_or_create_with_alias(self, name, required=False):
         tag = self.get_by_alias(name)
@@ -150,7 +140,7 class Tag(models.Model, Viewable):
             elif alias.locale == DEFAULT_LOCALE:
                 default_tag_name = alias.name
 
-        return localized_tag_name if localized_tag_name else default_tag_name
+        return localized_tag_name or default_tag_name
 
     def get_view(self):
         name = self.get_localized_name()
@@ -175,10 +165,6 class Tag(models.Model, Viewable):
             posts = posts.filter(thread__status__in=status)
         return posts.order_by('?').first()
 
-    def get_first_letter(self):
-        name = self.get_localized_name()
-        return name and name[0] or ''
-
     def get_related_tags(self):
         return set(Tag.objects.filter(thread_tags__in=self.get_threads()).exclude(
             id=self.id).order_by('?')[:RELATED_TAGS_COUNT])
@@ -209,4 +195,3 class Tag(models.Model, Viewable):
         return Attachment.objects.filter(
             attachment_posts__thread__tags__in=[self]).filter(
             mimetype__in=FILE_TYPES_IMAGE).order_by('-attachment_posts__pub_time')
-