Merge pull request #2 from udacity/update_django

[osqa.git] / forum / models / tag.py

diff --git a/forum/models/tag.py b/forum/models/tag.py
index 3d3b8e870180f5af00aa51223e5bdb777d0dae96..eca23e468ae8d186605b5989831191284a8fed77 100644 (file)
--- a/forum/models/tag.py
+++ b/forum/models/tag.py
@@ -1,36 +1,71 @@
+import datetime
 from base import *
 
+from django.conf import settings as django_settings
+from django.core.cache.backends.base import BaseCache
 from django.utils.translation import ugettext as _
-import django.dispatch
+from django.utils.encoding import smart_unicode, force_unicode
 
-class ActiveTagManager(models.Manager):
-    def get_query_set(self):
-        return super(ActiveTagManager, self).get_query_set().exclude(used_count__lt=1)
+from forum import modules
 
+class ActiveTagManager(CachedManager):
+    use_for_related_fields = True
+
+    def get_queryset(self):
+        return super(ActiveTagManager, self).get_queryset().exclude(used_count__lt=1)
 
 class Tag(BaseModel):
     name            = models.CharField(max_length=255, unique=True)
     created_by      = models.ForeignKey(User, related_name='created_tags')
+    created_at      = models.DateTimeField(default=datetime.datetime.now, blank=True, null=True)
     marked_by       = models.ManyToManyField(User, related_name="marked_tags", through="MarkedTag")
     # Denormalised data
     used_count = models.PositiveIntegerField(default=0)
 
     active = ActiveTagManager()
 
-
     class Meta:
         ordering = ('-used_count', 'name')
         app_label = 'forum'
 
     def __unicode__(self):
-        return self.name
+        return force_unicode(self.name)
+
+    def add_to_usage_count(self, value):
+        if self.used_count + value < 0:
+            self.used_count = 0
+        else:
+            self.used_count = models.F('used_count') + value
+
+    def cache_key(self):
+        return self._generate_cache_key(Tag.safe_cache_name(self.name))
+
+    @classmethod
+    def safe_cache_name(cls, name):
+        return "".join([str(ord(c)) for c in name])
+
+    @classmethod
+    def infer_cache_key(cls, querydict):
+        if 'name' in querydict:
+            cache_key = cls._generate_cache_key(cls.safe_cache_name(querydict['name']))
+
+            if len(cache_key) > django_settings.CACHE_MAX_KEY_LENGTH:
+                cache_key = cache_key[:django_settings.CACHE_MAX_KEY_LENGTH]
+
+            return cache_key
+
+        return None
+
+    @classmethod
+    def value_to_list_on_cache_query(cls):
+        return 'name'
 
     @models.permalink
     def get_absolute_url(self):
         return ('tag_questions', (), {'tag': self.name})
 
 class MarkedTag(models.Model):
-    TAG_MARK_REASONS = (('good',_('interesting')),('bad',_('ignored')))
+    TAG_MARK_REASONS = (('good', _('interesting')), ('bad', _('ignored')))
     tag = models.ForeignKey(Tag, related_name='user_selections')
     user = models.ForeignKey(User, related_name='tag_selections')
     reason = models.CharField(max_length=16, choices=TAG_MARK_REASONS)