1 files changed, 90 insertions, 0 deletions
diff --git a/coip/apps/resource/models.py b/coip/apps/resource/models.py
new file mode 100644
index 0000000..7282ae6
--- /dev/null
+++ b/coip/apps/resource/models.py
@@ -0,0 +1,90 @@
+'''
+Created on Apr 10, 2012
+
+@author: leifj
+'''
+
+from django.db import models
+from django.db.models.fields import DateTimeField
+from django.contrib.contenttypes.models import ContentType
+from django.contrib.contenttypes import generic
+from django_extensions.db.fields import UUIDField
+from django.dispatch.dispatcher import receiver
+from django.db.models.signals import post_save, pre_delete
+from django.core.exceptions import ObjectDoesNotExist
+from django.db.models.base import ModelBase
+
+class NotAModel(Exception):
+    pass
+
+class RecursiveRegistration(Exception):
+    pass
+
+class UninitializedObject(Exception):
+    pass
+
+class Resource(models.Model):
+    uuid = UUIDField(unique=True)
+    content_type = models.ForeignKey(ContentType)
+    object_id = models.PositiveIntegerField()
+    content_object = generic.GenericForeignKey('content_type', 'object_id')
+    lastupdated = DateTimeField(auto_now=True)
+    timecreated = DateTimeField(auto_now_add=True)
+    
+    def __unicode__(self):
+        return self.uuid
+        
+def object_for_uuid(uuid):
+    try:
+        r = Resource.objects.get(uuid=uuid)
+        return r.content_object
+    except ObjectDoesNotExist:
+        return None
+
+def uuid_for_object(o):
+    if not o.id:
+        raise UninitializedObject("Can't obtain uuid for non-persisted objects")
+    
+    typ = ContentType.objects.get_for_model(o)
+    r,cr = Resource.objects.get_or_create(object_id=o.id,content_type=typ)
+    return r.uuid
+
+def add_resource(o):
+    typ = ContentType.objects.get_for_model(o)
+    r,cr = Resource.objects.get_or_create(object_id=o.id,content_type=typ)
+    return r.uuid
+
+def delete_resource(o):
+    typ = ContentType.objects.get_for_model(o)
+    try:
+        r = Resource.objects.get(object_id=o.id,content_type=typ)
+        r.delete()
+    except ObjectDoesNotExist:
+        pass
+
+class ResourceClassRegistry():
+    def __init__(self):
+        self._registry = []
+
+    def register(self,model,addField=True):
+        if not isinstance(model,ModelBase):
+            raise NotAModel('%s does not appear to be a model!' % model)
+        if not model in self._registry:
+            if addField:
+                setattr(model,'uuid',property(lambda x: uuid_for_object(x)))
+            self._registry.append(model)
+            
+resources = ResourceClassRegistry()
+
+def register(model):
+    resources.register(model)
+
+@receiver(post_save)
+def auto_create_resource(sender,**kwargs):
+    if sender in resources._registry and kwargs['created']:
+        add_resource(kwargs['instance'])
+
+@receiver(pre_delete)
+def auto_delete_resource(sender,**kwargs):
+    if sender in resources._registry:
+        delete_resource(kwargs['instance'])