Ticket #9522: 9522.patch

django/db/models/fields/__init__.py

@@ -52 +52 @@
     # Designates whether empty strings fundamentally are allowed at the
     # database level.
     empty_strings_allowed = True
+    
+    # Designates whether this field's value must be converted to string
+    # by `value_to_string` method while serialization
+    serialize_to_string = False
 
     # These track each time a Field instance is created. Used to retain order.
     # The auto_creation_counter is used for fields that Django implicitly

django/core/serializers/python.py

@@ -35 +35 @@
         self._current = None
 
     def handle_field(self, obj, field):
-        self._current[field.name] = smart_unicode(getattr(obj, field.name), strings_only=True)
+        if field.serialize_to_string:
+            value = self.get_string_value(obj, field)
+        else:
+            value = smart_unicode(getattr(obj, field.name), strings_only=True)
+        self._current[field.name] = value
 
     def handle_fk_field(self, obj, field):
         related = getattr(obj, field.name)

tests/modeltests/serializers/models.py

@@ -67 +67 @@
 class Score(models.Model):
     score = models.FloatField()
 
+
+class Team(object):
+    def __init__(self, title):
+        self.title = title
+        
+    def __unicode__(self):
+        raise NotImplementedError("Not so simple")
+    
+    def __str__(self):
+        raise NotImplementedError("Not so simple")
+    
+    def to_string(self):
+        return "%s" % self.title
+    
+class TeamField(models.CharField):
+    __metaclass__ = models.SubfieldBase
+    
+    serialize_to_string = True
+    
+    def __init__(self):
+        super(TeamField, self).__init__(max_length=100)
+    
+    def get_db_prep_save(self, value):
+        return unicode(value.title)
+    
+    def to_python(self, value):
+        if isinstance(value, Team):
+            return value
+        return Team(value)
+    
+    def value_to_string(self, obj):
+        return self._get_val_from_obj(obj).to_string()
+    
+class Player(models.Model):
+    rank = models.IntegerField()
+    team = TeamField()
+    
+    def __unicode__(self):
+        return self.team.to_string()
+
 __test__ = {'API_TESTS':"""
 # Create some data:
 >>> from datetime import datetime
@@ -217 +257 @@
 >>> print list(serializers.deserialize('json', serializers.serialize('json', [sc])))[0].object.score
 3.4
 
+
+# Custom field with non trivial to string convertion value
+>>> player = Player()
+>>> player.rank = 1
+>>> player.team = Team("Spartak Moskva")
+>>> player.save()
+
+>>> serialized =  serializers.serialize("json", Player.objects.all())
+>>> print serialized
+[{"pk": 1, "model": "serializers.player", "fields": {"rank": 1, "team": "Spartak Moskva"}}]
+
+>>> obj = list(serializers.deserialize("yaml", serialized))[0]
+>>> print obj
+<DeserializedObject: Spartak Moskva>
 """}
 
 try:
@@ -253 +307 @@
 <DeserializedObject: Just kidding; I love TV poker>
 <DeserializedObject: Time to reform copyright>
 
+# Custom field with non trivial to string convertion value with YAML serializer
+
+>>> print serializers.serialize("yaml", Player.objects.all())
+- fields: {rank: 1, team: Spartak Moskva}
+  model: serializers.player
+  pk: 1
+<BLANKLINE>
+
 """
 except ImportError:
     pass