--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/thirdparty/google_appengine/lib/django/tests/modeltests/serializers/models.py	Tue Aug 26 21:49:54 2008 +0000
@@ -0,0 +1,162 @@
+"""
+41. Serialization
+
+``django.core.serializers`` provides interfaces to converting Django querysets
+to and from "flat" data (i.e. strings).
+"""
+
+from django.db import models
+
+class Category(models.Model):
+    name = models.CharField(maxlength=20)
+
+    class Meta:
+       ordering = ('name',)
+
+    def __str__(self):
+        return self.name
+
+class Author(models.Model):
+    name = models.CharField(maxlength=20)
+
+    class Meta:
+        ordering = ('name',)
+    
+    def __str__(self):
+        return self.name
+
+class Article(models.Model):
+    author = models.ForeignKey(Author)
+    headline = models.CharField(maxlength=50)
+    pub_date = models.DateTimeField()
+    categories = models.ManyToManyField(Category)
+
+    class Meta:
+       ordering = ('pub_date',)
+
+    def __str__(self):
+        return self.headline
+
+class AuthorProfile(models.Model):
+    author = models.OneToOneField(Author)
+    date_of_birth = models.DateField()
+    
+    def __str__(self):
+        return "Profile of %s" % self.author
+
+__test__ = {'API_TESTS':"""
+# Create some data:
+>>> from datetime import datetime
+>>> sports = Category(name="Sports")
+>>> music = Category(name="Music")
+>>> op_ed = Category(name="Op-Ed")
+>>> sports.save(); music.save(); op_ed.save()
+
+>>> joe = Author(name="Joe")
+>>> jane = Author(name="Jane")
+>>> joe.save(); jane.save()
+
+>>> a1 = Article(
+...     author = jane,
+...     headline = "Poker has no place on ESPN",
+...     pub_date = datetime(2006, 6, 16, 11, 00))
+>>> a2 = Article(
+...     author = joe,
+...     headline = "Time to reform copyright",
+...     pub_date = datetime(2006, 6, 16, 13, 00))
+>>> a1.save(); a2.save()
+>>> a1.categories = [sports, op_ed]
+>>> a2.categories = [music, op_ed]
+
+# Serialize a queryset to XML
+>>> from django.core import serializers
+>>> xml = serializers.serialize("xml", Article.objects.all())
+
+# The output is valid XML
+>>> from xml.dom import minidom
+>>> dom = minidom.parseString(xml)
+
+# Deserializing has a similar interface, except that special DeserializedObject
+# instances are returned.  This is because data might have changed in the 
+# database since the data was serialized (we'll simulate that below).
+>>> for obj in serializers.deserialize("xml", xml):
+...     print obj
+<DeserializedObject: Poker has no place on ESPN>
+<DeserializedObject: Time to reform copyright>
+
+# Deserializing data with different field values doesn't change anything in the
+# database until we call save():
+>>> xml = xml.replace("Poker has no place on ESPN", "Poker has no place on television")
+>>> objs = list(serializers.deserialize("xml", xml))
+
+# Even those I deserialized, the database hasn't been touched
+>>> Article.objects.all()
+[<Article: Poker has no place on ESPN>, <Article: Time to reform copyright>]
+
+# But when I save, the data changes as you might except.
+>>> objs[0].save()
+>>> Article.objects.all()
+[<Article: Poker has no place on television>, <Article: Time to reform copyright>]
+
+# Django also ships with a built-in JSON serializers
+>>> json = serializers.serialize("json", Category.objects.filter(pk=2))
+>>> json
+'[{"pk": "2", "model": "serializers.category", "fields": {"name": "Music"}}]'
+
+# You can easily create new objects by deserializing data with an empty PK
+# (It's easier to demo this with JSON...)
+>>> new_author_json = '[{"pk": null, "model": "serializers.author", "fields": {"name": "Bill"}}]'
+>>> for obj in serializers.deserialize("json", new_author_json):
+...     obj.save()
+>>> Author.objects.all()
+[<Author: Bill>, <Author: Jane>, <Author: Joe>]
+
+# All the serializers work the same
+>>> json = serializers.serialize("json", Article.objects.all())
+>>> for obj in serializers.deserialize("json", json):
+...     print obj
+<DeserializedObject: Poker has no place on television>
+<DeserializedObject: Time to reform copyright>
+
+>>> json = json.replace("Poker has no place on television", "Just kidding; I love TV poker")
+>>> for obj in serializers.deserialize("json", json):
+...     obj.save()
+
+>>> Article.objects.all()
+[<Article: Just kidding; I love TV poker>, <Article: Time to reform copyright>]
+
+# If you use your own primary key field (such as a OneToOneField), 
+# it doesn't appear in the serialized field list - it replaces the
+# pk identifier.
+>>> profile = AuthorProfile(author=joe, date_of_birth=datetime(1970,1,1))
+>>> profile.save()
+
+>>> json = serializers.serialize("json", AuthorProfile.objects.all())
+>>> json
+'[{"pk": "1", "model": "serializers.authorprofile", "fields": {"date_of_birth": "1970-01-01"}}]'
+
+>>> for obj in serializers.deserialize("json", json):
+...     print obj
+<DeserializedObject: Profile of Joe>
+
+# Objects ids can be referenced before they are defined in the serialization data
+# However, the deserialization process will need to be contained within a transaction
+>>> json = '[{"pk": "3", "model": "serializers.article", "fields": {"headline": "Forward references pose no problem", "pub_date": "2006-06-16 15:00:00", "categories": [4, 1], "author": 4}}, {"pk": "4", "model": "serializers.category", "fields": {"name": "Reference"}}, {"pk": "4", "model": "serializers.author", "fields": {"name": "Agnes"}}]'
+>>> from django.db import transaction
+>>> transaction.enter_transaction_management()
+>>> transaction.managed(True)
+>>> for obj in serializers.deserialize("json", json):
+...     obj.save()
+
+>>> transaction.commit()
+>>> transaction.leave_transaction_management()
+
+>>> article = Article.objects.get(pk=3)
+>>> article
+<Article: Forward references pose no problem>
+>>> article.categories.all()
+[<Category: Reference>, <Category: Sports>]
+>>> article.author
+<Author: Agnes>
+
+"""}