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1 """ |
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2 Custom managers for Django models registered with the tagging |
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3 application. |
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4 """ |
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5 from django.contrib.contenttypes.models import ContentType |
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6 from django.db import models |
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7 |
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8 from tagging.models import Tag, TaggedItem |
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9 |
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10 class ModelTagManager(models.Manager): |
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11 """ |
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12 A manager for retrieving tags for a particular model. |
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13 """ |
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14 def get_query_set(self): |
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15 ctype = ContentType.objects.get_for_model(self.model) |
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16 return Tag.objects.filter( |
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17 items__content_type__pk=ctype.pk).distinct() |
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18 |
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19 def cloud(self, *args, **kwargs): |
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20 return Tag.objects.cloud_for_model(self.model, *args, **kwargs) |
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21 |
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22 def related(self, tags, *args, **kwargs): |
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23 return Tag.objects.related_for_model(tags, self.model, *args, **kwargs) |
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24 |
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25 def usage(self, *args, **kwargs): |
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26 return Tag.objects.usage_for_model(self.model, *args, **kwargs) |
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27 |
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28 class ModelTaggedItemManager(models.Manager): |
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29 """ |
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30 A manager for retrieving model instances based on their tags. |
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31 """ |
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32 def related_to(self, obj, queryset=None, num=None): |
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33 if queryset is None: |
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34 return TaggedItem.objects.get_related(obj, self.model, num=num) |
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35 else: |
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36 return TaggedItem.objects.get_related(obj, queryset, num=num) |
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37 |
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38 def with_all(self, tags, queryset=None): |
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39 if queryset is None: |
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40 return TaggedItem.objects.get_by_model(self.model, tags) |
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41 else: |
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42 return TaggedItem.objects.get_by_model(queryset, tags) |
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43 |
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44 def with_any(self, tags, queryset=None): |
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45 if queryset is None: |
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46 return TaggedItem.objects.get_union_by_model(self.model, tags) |
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47 else: |
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48 return TaggedItem.objects.get_union_by_model(queryset, tags) |
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49 |
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50 class TagDescriptor(object): |
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51 """ |
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52 A descriptor which provides access to a ``ModelTagManager`` for |
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53 model classes and simple retrieval, updating and deletion of tags |
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54 for model instances. |
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55 """ |
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56 def __get__(self, instance, owner): |
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57 if not instance: |
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58 tag_manager = ModelTagManager() |
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59 tag_manager.model = owner |
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60 return tag_manager |
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61 else: |
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62 return Tag.objects.get_for_object(instance) |
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63 |
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64 def __set__(self, instance, value): |
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65 Tag.objects.update_tags(instance, value) |
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66 |
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67 def __delete__(self, instance): |
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68 Tag.objects.update_tags(instance, None) |