Fixed #280 -- Added _pre_delete() and _post_delete() hooks. Also updated the docs and added a unit testdjango/core/meta/__init__.py

git-svn-id: http://code.djangoproject.com/svn/django/trunk@432 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/model-api.txt

@@ -728,6 +728,12 @@ There are a few object methods that have special meaning:
     This method is called just after the object is saved to the database. This
     could be used to update other tables, update cached information, etc.
 
+``_pre_delete``
+    Like ``_pre_save``, but for deletion.
+
+``_post_delete``
+    Like ``_post_save``, but for deletion.
+
 Module-level methods
 --------------------
 

tests/testapp/models/save_delete_hooks.py

@@ -0,0 +1,51 @@
+"""
+13. Adding hooks before/after saving and deleting.
+
+Django provides hooks for executing arbitrary code around ``save()`` and
+``delete()``. Just add any of the following methods to your model:
+
+    * ``_pre_save()`` is called before an object is saved.
+    * ``_post_save()`` is called after an object is saved.
+    * ``_pre_delete()`` is called before an object is deleted.
+    * ``_post_delete()`` is called after an object is deleted.
+"""
+
+from django.core import meta
+
+class Person(meta.Model):
+    fields = (
+        meta.CharField('first_name', maxlength=20),
+        meta.CharField('last_name', maxlength=20),
+    )
+
+    def __repr__(self):
+        return "%s %s" % (self.first_name, self.last_name)
+
+    def _pre_save(self):
+        print "Before save"
+
+    def _post_save(self):
+        print "After save"
+
+    def _pre_delete(self):
+        print "Before deletion"
+
+    def _post_delete(self):
+        print "After deletion"
+
+API_TESTS = """
+>>> p1 = persons.Person(first_name='John', last_name='Smith')
+>>> p1.save()
+Before save
+After save
+
+>>> persons.get_list()
+[John Smith]
+
+>>> p1.delete()
+Before deletion
+After deletion
+
+>>> persons.get_list()
+[]
+"""