forum/models/tag.py

   1 import datetime
   2 from base import *
   3
   4 from django.conf import settings as django_settings
   5 from django.core.cache.backends.base import BaseCache
   6 from django.utils.translation import ugettext as _
   7 from django.utils.encoding import smart_unicode, force_unicode
   8
   9 from forum import modules
  10
  11 class ActiveTagManager(CachedManager):
  12     use_for_related_fields = True
  13
  14     def get_query_set(self):
  15         return super(ActiveTagManager, self).get_query_set().exclude(used_count__lt=1)
  16
  17 class Tag(BaseModel):
  18     name            = models.CharField(max_length=255, unique=True)
  19     created_by      = models.ForeignKey(User, related_name='created_tags')
  20     created_at      = models.DateTimeField(default=datetime.datetime.now, blank=True, null=True)
  21     marked_by       = models.ManyToManyField(User, related_name="marked_tags", through="MarkedTag")
  22     # Denormalised data
  23     used_count = models.PositiveIntegerField(default=0)
  24
  25     active = ActiveTagManager()
  26
  27     class Meta:
  28         ordering = ('-used_count', 'name')
  29         app_label = 'forum'
  30
  31     def __unicode__(self):
  32         return force_unicode(self.name)
  33
  34     def add_to_usage_count(self, value):
  35         if int(self.used_count + value) < 0:
  36             self.used_count = 0
  37         else:
  38             self.used_count += value
  39
  40         self.save()
  41
  42     def cache_key(self):
  43         return self._generate_cache_key(Tag.safe_cache_name(self.name))
  44
  45     @classmethod
  46     def safe_cache_name(cls, name):
  47         return "".join([str(ord(c)) for c in name])
  48
  49     @classmethod
  50     def infer_cache_key(cls, querydict):
  51         if 'name' in querydict:
  52             cache_key = cls._generate_cache_key(cls.safe_cache_name(querydict['name']))
  53
  54             if len(cache_key) > django_settings.CACHE_MAX_KEY_LENGTH:
  55                 cache_key = cache_key[:django_settings.CACHE_MAX_KEY_LENGTH]
  56
  57             return cache_key
  58
  59         return None
  60
  61     @classmethod
  62     def value_to_list_on_cache_query(cls):
  63         return 'name'
  64
  65     @models.permalink
  66     def get_absolute_url(self):
  67         return ('tag_questions', (), {'tag': self.name})
  68
  69 class MarkedTag(models.Model):
  70     TAG_MARK_REASONS = (('good', _('interesting')), ('bad', _('ignored')))
  71     tag = models.ForeignKey(Tag, related_name='user_selections')
  72     user = models.ForeignKey(User, related_name='tag_selections')
  73     reason = models.CharField(max_length=16, choices=TAG_MARK_REASONS)
  74
  75     class Meta:
  76         app_label = 'forum'
  77