Use aggregation to get tags popularity

boards/models/tag.py

@@ -1,99 +1,103 b''
 from boards.models import Thread, Post
 from django.db import models
-from django.db.models import Count
+from django.db.models import Count, Sum
 
 __author__ = 'neko259'
 
 MAX_TAG_FONT = 1
 MIN_TAG_FONT = 0.2
 
 TAG_POPULARITY_MULTIPLIER = 20
 
 ARCHIVE_POPULARITY_MODIFIER = 0.5
 
 
 class TagManager(models.Manager):
 
     def get_not_empty_tags(self):
         tags = self.annotate(Count('threads')) \
             .filter(threads__count__gt=0).order_by('name')
 
         return tags
 
 
 class Tag(models.Model):
     """
     A tag is a text node assigned to the thread. The tag serves as a board
     section. There can be multiple tags for each thread
     """
 
     objects = TagManager()
 
     class Meta:
         app_label = 'boards'
 
     name = models.CharField(max_length=100)
     threads = models.ManyToManyField(Thread, null=True,
                                      blank=True, related_name='tag+')
     linked = models.ForeignKey('Tag', null=True, blank=True)
 
     def __unicode__(self):
         return self.name
 
     def is_empty(self):
         return self.get_thread_count() == 0
 
     def get_thread_count(self):
         return self.threads.count()
 
     def get_popularity(self):
         all_post_count = Post.objects.all().count()
 
         tag_reply_count = 0.0
 
         tag_reply_count += self.get_post_count()
         tag_reply_count +=\
             self.get_post_count(archived=True) * ARCHIVE_POPULARITY_MODIFIER
 
         popularity = tag_reply_count / all_post_count
 
         return popularity
 
     def get_linked_tags(self):
         tag_list = []
         self.get_linked_tags_list(tag_list)
 
         return tag_list
 
     def get_linked_tags_list(self, tag_list=[]):
         """
         Returns the list of tags linked to current. The list can be got
         through returned value or tag_list parameter
         """
 
         linked_tag = self.linked
 
         if linked_tag and not (linked_tag in tag_list):
             tag_list.append(linked_tag)
 
             linked_tag.get_linked_tags_list(tag_list)
 
     def get_font_value(self):
         """Get tag font value to differ most popular tags in the list"""
 
         popularity = self.get_popularity()
 
         font_value = popularity * Tag.objects.get_not_empty_tags().count()
         font_value = max(font_value, MIN_TAG_FONT)
         font_value = min(font_value, MAX_TAG_FONT)
 
         return str(font_value)
 
     def get_post_count(self, archived=False):
         posts_count = 0
 
-        for thread in self.threads.annotate(Count('replies')).filter(
-                archived=archived):
-            posts_count += thread.replies__count
+        threads = self.threads.filter(archived=archived)
+        if threads.exists():
+            posts_count = threads.annotate(posts_count=Count('replies')).aggregate(
+                posts_sum=Sum('posts_count'))['posts_sum']
+
+        if not posts_count:
+            posts_count = 0
 
         return posts_count