Ticket #13252: 13252.3.diff

File 13252.3.diff, 8.8 KB (added by Chris Beaven, 9 years ago)

now with tests/docs

  • django/core/serializers/base.py

    diff --git a/django/core/serializers/base.py b/django/core/serializers/base.py
    index 190636e..9f535e3 100644
    a b class DeserializedObject(object): 
    170170        # prevent a second (possibly accidental) call to save() from saving
    171171        # the m2m data twice.
    172172        self.m2m_data = None
     173
     174def build_instance(Model, data, db):
     175    """
     176    Build a model instance.
     177
     178    If the model instance doesn't have a primary key and the model supports
     179    natural keys, try to retrieve it from the database.
     180    """
     181    obj = Model(**data)
     182    if obj.pk is None and hasattr(Model, 'natural_key') and\
     183            hasattr(Model._default_manager, 'get_by_natural_key'):
     184        pk = obj.natural_key()
     185        try:
     186            obj.pk = Model._default_manager.db_manager(db)\
     187                                           .get_by_natural_key(*pk).pk
     188        except Model.DoesNotExist:
     189            pass
     190    return obj
  • django/core/serializers/python.py

    diff --git a/django/core/serializers/python.py b/django/core/serializers/python.py
    index a68ea21..839fee1 100644
    a b class Serializer(base.Serializer): 
    2727        self._current = {}
    2828
    2929    def end_object(self, obj):
    30         self.objects.append({
    31             "model"  : smart_unicode(obj._meta),
    32             "pk"     : smart_unicode(obj._get_pk_val(), strings_only=True),
    33             "fields" : self._current
    34         })
     30        data = {
     31            "model": smart_unicode(obj._meta),
     32            "fields": self._current
     33        }
     34        if not self.use_natural_keys or not hasattr(obj, 'natural_key'):
     35            data['pk'] = smart_unicode(obj._get_pk_val(), strings_only=True)
     36        self.objects.append(data)
    3537        self._current = None
    3638
    3739    def handle_field(self, obj, field):
    def Deserializer(object_list, **options): 
    8284    for d in object_list:
    8385        # Look up the model and starting build a dict of data for it.
    8486        Model = _get_model(d["model"])
    85         data = {Model._meta.pk.attname : Model._meta.pk.to_python(d["pk"])}
     87        data = {}
     88        if 'pk' in d:
     89            data[Model._meta.pk.attname] = Model._meta.pk.to_python(d['pk'])
    8690        m2m_data = {}
    8791
    8892        # Handle each field
    def Deserializer(object_list, **options): 
    127131            else:
    128132                data[field.name] = field.to_python(field_value)
    129133
    130         yield base.DeserializedObject(Model(**data), m2m_data)
     134        obj = base.build_instance(Model, data, db)
     135
     136        yield base.DeserializedObject(obj, m2m_data)
    131137
    132138def _get_model(model_identifier):
    133139    """
  • django/core/serializers/xml_serializer.py

    diff --git a/django/core/serializers/xml_serializer.py b/django/core/serializers/xml_serializer.py
    index 5fef3b6..4fcb400 100644
    a b class Serializer(base.Serializer): 
    4242            raise base.SerializationError("Non-model object (%s) encountered during serialization" % type(obj))
    4343
    4444        self.indent(1)
    45         self.xml.startElement("object", {
    46             "pk"    : smart_unicode(obj._get_pk_val()),
    47             "model" : smart_unicode(obj._meta),
    48         })
     45        object_data = {"model": smart_unicode(obj._meta)}
     46        if not self.use_natural_keys or not hasattr(obj, 'natural_key'):
     47            object_data['pk'] = smart_unicode(obj._get_pk_val())
     48        self.xml.startElement("object", object_data)
    4949
    5050    def end_object(self, obj):
    5151        """
    class Deserializer(base.Deserializer): 
    166166        # bail.
    167167        Model = self._get_model_from_node(node, "model")
    168168
    169         # Start building a data dictionary from the object.  If the node is
    170         # missing the pk attribute, bail.
    171         pk = node.getAttribute("pk")
    172         if not pk:
    173             raise base.DeserializationError("<object> node is missing the 'pk' attribute")
    174 
    175         data = {Model._meta.pk.attname : Model._meta.pk.to_python(pk)}
     169        # Start building a data dictionary from the object.
     170        data = {}
     171        if node.hasAttribute('pk'):
     172            data[Model._meta.pk.attname] = Model._meta.pk.to_python(
     173                                                    node.getAttribute('pk'))
    176174
    177175        # Also start building a dict of m2m data (this is saved as
    178176        # {m2m_accessor_attribute : [list_of_related_objects]})
    class Deserializer(base.Deserializer): 
    203201                    value = field.to_python(getInnerText(field_node).strip())
    204202                data[field.name] = value
    205203
     204        obj = base.build_instance(Model, data, self.db)
     205
    206206        # Return a DeserializedObject so that the m2m data has a place to live.
    207         return base.DeserializedObject(Model(**data), m2m_data)
     207        return base.DeserializedObject(obj, m2m_data)
    208208
    209209    def _handle_fk_field_node(self, node, field):
    210210        """
  • docs/topics/serialization.txt

    diff --git a/docs/topics/serialization.txt b/docs/topics/serialization.txt
    index 1cf8e86..475035c 100644
    a b into the primary key of an actual ``Person`` object. 
    313313    fields will be effectively unique, you can still use those fields
    314314    as a natural key.
    315315
     316.. versionadded:: 1.3
     317
     318Deserialization of objects with no primary key will always check whether the
     319model's manager has a ``get_by_natural_key()`` method and if so, use it to
     320populate the deserialized object's primary key.
     321
    316322Serialization of natural keys
    317323~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    318324
    use the `--natural` command line flag to generate natural keys. 
    359365    natural keys during serialization, but *not* be able to load those
    360366    key values, just don't define the ``get_by_natural_key()`` method.
    361367
     368.. versionadded:: 1.3
     369
     370When ``use_natural_keys=True`` is specified, the primary key is no longer
     371provided in the serialized data of this object since it can be calculated
     372during deserialization::
     373
     374    ...
     375    {
     376        "model": "store.person",
     377        "fields": {
     378            "first_name": "Douglas",
     379            "last_name": "Adams",
     380            "birth_date": "1952-03-11",
     381        }
     382    }
     383    ...
     384
    362385Dependencies during serialization
    363386~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    364387
  • tests/regressiontests/serializers_regress/models.py

    diff --git a/tests/regressiontests/serializers_regress/models.py b/tests/regressiontests/serializers_regress/models.py
    index bec0a98..32c55c0 100644
    a b class LengthModel(models.Model): 
    264264
    265265    def __len__(self):
    266266        return self.data
     267
     268#Tests for natural keys.
     269class BookManager(models.Manager):
     270    def get_by_natural_key(self, isbn13):
     271        return self.get(isbn13=isbn13)
     272
     273class Book(models.Model):
     274    isbn13 = models.CharField(max_length=14)
     275    title = models.CharField(max_length=100)
     276
     277    objects = BookManager()
     278
     279    def natural_key(self):
     280        return (self.isbn13,)
  • tests/regressiontests/serializers_regress/tests.py

    diff --git a/tests/regressiontests/serializers_regress/tests.py b/tests/regressiontests/serializers_regress/tests.py
    index be920c6..a67f429 100644
    a b def streamTest(format, self): 
    414414    self.assertEqual(string_data, stream.getvalue())
    415415    stream.close()
    416416
     417def naturalKeyTest(format, self):
     418    book1 = {'isbn13': '978-1590597255', 'title': 'The Definitive Guide to '
     419             'Django: Web Development Done Right'}
     420    book2 = {'isbn13':'978-1590599969', 'title': 'Practical Django Projects'}
     421
     422    # Create the books.
     423    adrian = Book.objects.create(**book1)
     424    james = Book.objects.create(**book2)
     425
     426    # Serialize the books.
     427    string_data = serializers.serialize(format, Book.objects.all(), indent=2,
     428                                        use_natural_keys=True)
     429
     430    # Delete one book (to prove that the natural key generation will only
     431    # restore the primary keys of books found in the database via the
     432    # get_natural_key manager method).
     433    james.delete()
     434
     435    # Deserialize and test.
     436    books = list(serializers.deserialize(format, string_data))
     437    self.assertEqual(len(books), 2)
     438    self.assertEqual(books[0].object.title, book1['title'])
     439    self.assertEqual(books[0].object.pk, adrian.pk)
     440    self.assertEqual(books[1].object.title, book2['title'])
     441    self.assertEqual(books[1].object.pk, None)
     442
    417443for format in serializers.get_serializer_formats():
    418444    setattr(SerializerTests, 'test_' + format + '_serializer', curry(serializerTest, format))
    419445    setattr(SerializerTests, 'test_' + format + '_serializer_fields', curry(fieldsTest, format))
     446    setattr(SerializerTests, 'test_' + format + '_serializer_natural_key',
     447            curry(naturalKeyTest, format))
    420448    if format != 'python':
    421449        setattr(SerializerTests, 'test_' + format + '_serializer_stream', curry(streamTest, format))
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