from models import Vote, Score from django.db.models import IntegerField, PositiveIntegerField import forms from django.contrib.contenttypes.models import ContentType from django.conf import settings if 'django.contrib.contenttypes' not in settings.INSTALLED_APPS: raise ImportError("djangoratings requires django.contrib.contenttypes in your INSTALLED_APPS") __all__ = ('Rating', 'RatingField', 'AnonymousRatingField') # The following code is based on the FuzzyDate snippet # http://blog.elsdoerfer.name/2008/01/08/fuzzydates-or-one-django-model-field-multiple-database-columns/ try: from hashlib import md5 except ImportError: from md5 import new as md5 def md5_hexdigest(value): return md5(value).hexdigest() class Rating(object): def __init__(self, score, votes): self.score = score self.votes = votes class RatingManager(object): def __init__(self, instance, field): self.content_type = None self.instance = instance self.field = field self.votes_field_name = "%s_votes" % (self.field.name,) self.score_field_name = "%s_score" % (self.field.name,) def get_percent(self): # hackish return float(self.score)/(self.votes*self.field.choices[-1][0])*100 def get_rating(self, user, ip_address): kwargs = dict( content_type = self.get_content_type(), object_id = self.instance.id, key = self.field.key, ) if user and not user.is_authenticated(): kwargs['user__isnull'] = True kwargs['ip_address'] = ip_address else: kwargs['user'] = user try: rating = Vote.objects.get(**kwargs) return rating.score except Vote.DoesNotExist: pass return def add(self, score, user, ip_address): """Used to add a rating to an object.""" if score not in dict(self.field.choices).keys(): raise ValueError("%s is not a valid choice for %s" % (score, self.field.name)) is_anonymous = (user is None or not user.is_authenticated()) if is_anonymous and not self.field.allow_anonymous: raise TypeError("user must be a user, not '%r'" % (user,)) if is_anonymous: user = None defaults = dict( score = score, ip_address = ip_address, ) kwargs = dict( content_type = self.get_content_type(), object_id = self.instance.id, key = self.field.key, user = user, ) if not user: kwargs['ip_address'] = ip_address try: rating, created = Vote.objects.get(**kwargs), False except Vote.DoesNotExist: kwargs.update(defaults) rating, created = Vote.objects.create(**kwargs), True has_changed = False if not created: if self.field.can_change_vote: has_changed = True self.score -= rating.score rating.score = score rating.save() else: return else: has_changed = True self.votes += 1 if has_changed: self.score += rating.score self.instance.save() #setattr(self.instance, self.field.name, Rating(score=self.score, votes=self.votes)) defaults = dict( score = self.score, votes = self.votes, ) kwargs = dict( content_type = self.get_content_type(), object_id = self.instance.id, key = self.field.key, ) try: score, created = Score.objects.get(**kwargs), False except Score.DoesNotExist: kwargs.update(defaults) score, created = Score.objects.create(**kwargs), True if not created: score.__dict__.update(defaults) score.save() def _get_votes(self, default=None): return getattr(self.instance, self.votes_field_name, default) def _set_votes(self, value): return setattr(self.instance, self.votes_field_name, value) votes = property(_get_votes, _set_votes) def _get_score(self, default=None): return getattr(self.instance, self.score_field_name, default) def _set_score(self, value): return setattr(self.instance, self.score_field_name, value) score = property(_get_score, _set_score) def get_content_type(self): if self.content_type is None: self.content_type = ContentType.objects.get_for_model(self.instance,) return self.content_type def delete(self, user, ip_address): is_anonymous = (user is None or not user.is_authenticated()) if is_anonymous: user = None kwargs = dict( content_type = self.get_content_type(), object_id = self.instance.id, key = self.field.key, user = user, ) if not user: kwargs['ip_address'] = ip_address try: rating = Vote.objects.get(**kwargs) self.score -= rating.score self.votes -= 1 self.instance.save() rating.delete() del kwargs['user'] try: del kwargs['ip_address'] except KeyError: pass score = Score.objects.get(**kwargs) score.__dict__.update({'score': self.score, 'votes': self.votes}) score.save() except (Vote.DoesNotExist, Score.DoesNotExist): raise ValueError("user hasn't voted yet.") class RatingCreator(object): def __init__(self, field): self.field = field self.votes_field_name = "%s_votes" % (self.field.name,) self.score_field_name = "%s_score" % (self.field.name,) # we need a unique key incase there are multiple ratings on a model self._rating_manager = None def __get__(self, instance, type=None): if instance is None: raise AttributeError('Can only be accessed via an instance.') return RatingManager(instance, self.field) def __set__(self, instance, value): if isinstance(value, Rating): setattr(instance, self.votes_field_name, value.votes) setattr(instance, self.score_field_name, value.score) else: raise TypeError("%s value must be a Rating instance, not '%r'" % (self.field.name, value)) class RatingField(IntegerField): """ A rating field contributes two columns to the model instead of the standard single column. """ def __init__(self, *args, **kwargs): if 'choices' not in kwargs: raise TypeError("%s missing required attribute 'choices'" % (self.__class__.__name__,)) self.can_change_vote = kwargs.pop('can_change_vote', False) self.allow_anonymous = kwargs.pop('allow_anonymous', False) kwargs['editable'] = False kwargs['default'] = 0 kwargs['blank'] = True super(RatingField, self).__init__(*args, **kwargs) def contribute_to_class(self, cls, name): self.name = name # Votes tally field votes_field = PositiveIntegerField( editable=False, default=0, blank=True) cls.add_to_class("%s_votes" % (self.name,), votes_field) # Score sum field score_field = IntegerField( editable=False, default=0, blank=True) cls.add_to_class("%s_score" % (self.name,), score_field) self.key = md5_hexdigest(self.name) setattr(cls, name, RatingCreator(self)) def get_db_prep_save(self, value): # XXX: what happens here? pass def get_db_prep_lookup(self, lookup_type, value): # TODO: hack in support for __score and __votes raise NotImplementedError(self.get_db_prep_lookup) if lookup_type == 'exact': return [self.get_db_prep_save(value)] elif lookup_type == 'in': return [self.get_db_prep_save(v) for v in value] else: return super(RatingField, self).get_db_prep_lookup(lookup_type, value) def formfield(self, **kwargs): defaults = {'form_class': forms.RatingField} defaults.update(kwargs) return super(RatingField, self).formfield(**defaults) # TODO: flatten_data method class AnonymousRatingField(RatingField): allow_anonymous = True