Merge pull request #744 from tomchristie/basic-bulk-edit

Basic bulk create and bulk update

docs/api-guide/fields.md

@@ -273,6 +273,49 @@ Django's regular [FILE_UPLOAD_HANDLERS] are used for handling uploaded files.
 
 ---
 
+# Custom fields
+
+If you want to create a custom field, you'll probably want to override either one or both of the `.to_native()` and `.from_native()` methods.  These two methods are used to convert between the intial datatype, and a primative, serializable datatype.  Primative datatypes may be any of a number, string, date/time/datetime or None.  They may also be any list or dictionary like object that only contains other primative objects.
+
+The `.to_native()` method is called to convert the initial datatype into a primative, serializable datatype.  The `from_native()` method is called to restore a primative datatype into it's initial representation.
+
+## Examples
+
+Let's look at an example of serializing a class that represents an RGB color value:
+
+    class Color(object):
+        """
+        A color represented in the RGB colorspace.
+        """
+        def __init__(self, red, green, blue):
+            assert(red >= 0 and green >= 0 and blue >= 0)
+            assert(red < 256 and green < 256 and blue < 256)
+            self.red, self.green, self.blue = red, green, blue
+
+    class ColourField(serializers.WritableField):
+        """
+        Color objects are serialized into "rgb(#, #, #)" notation.
+        """
+        def to_native(self, obj):
+            return "rgb(%d, %d, %d)" % (obj.red, obj.green, obj.blue)
+      
+        def from_native(self, data):
+            data = data.strip('rgb(').rstrip(')')
+            red, green, blue = [int(col) for col in data.split(',')]
+            return Color(red, green, blue)
+            
+
+By default field values are treated as mapping to an attribute on the object.  If you need to customize how the field value is accessed and set you need to override `.field_to_native()` and/or `.field_from_native()`.
+
+As an example, let's create a field that can be used represent the class name of the object being serialized:
+
+    class ClassNameField(serializers.Field):
+        def field_to_native(self, obj, field_name):
+            """
+            Serialize the object's class name.
+            """
+            return obj.__class__
+
 [cite]: https://docs.djangoproject.com/en/dev/ref/forms/api/#django.forms.Form.cleaned_data
 [FILE_UPLOAD_HANDLERS]: https://docs.djangoproject.com/en/dev/ref/settings/#std:setting-FILE_UPLOAD_HANDLERS
 [strftime]: http://docs.python.org/2/library/datetime.html#strftime-and-strptime-behavior

rest_framework/serializers.py

@@ -110,13 +110,15 @@ class BaseSerializer(Field):
     _dict_class = SortedDictWithMetadata
 
     def __init__(self, instance=None, data=None, files=None,
-                 context=None, partial=False, many=None, source=None):
+                 context=None, partial=False, many=None, source=None,
+                 allow_delete=False):
         super(BaseSerializer, self).__init__(source=source)
         self.opts = self._options_class(self.Meta)
         self.parent = None
         self.root = None
         self.partial = partial
         self.many = many
+        self.allow_delete = allow_delete
 
         self.context = context or {}
 
@@ -128,6 +130,13 @@ class BaseSerializer(Field):
         self._data = None
         self._files = None
         self._errors = None
+        self._deleted = None
+
+        if many and instance is not None and not hasattr(instance, '__iter__'):
+            raise ValueError('instance should be a queryset or other iterable with many=True')
+
+        if allow_delete and not many:
+            raise ValueError('allow_delete should only be used for bulk updates, but you have not set many=True')
 
     #####
     # Methods to determine which fields to use when (de)serializing objects.
@@ -331,6 +340,20 @@ class BaseSerializer(Field):
             return [self.to_native(item) for item in obj]
         return self.to_native(obj)
 
+    def get_identity(self, data):
+        """
+        This hook is required for bulk update.
+        It is used to determine the canonical identity of a given object.
+
+        Note that the data has not been validated at this point, so we need
+        to make sure that we catch any cases of incorrect datatypes being
+        passed to this method.
+        """
+        try:
+            return data.get('id', None)
+        except AttributeError:
+            return None
+
     @property
     def errors(self):
         """
@@ -352,10 +375,33 @@ class BaseSerializer(Field):
             if many:
                 ret = []
                 errors = []
-                for item in data:
-                    ret.append(self.from_native(item, None))
-                    errors.append(self._errors)
-                self._errors = any(errors) and errors or []
+                update = self.object is not None
+
+                if update:
+                    # If this is a bulk update we need to map all the objects
+                    # to a canonical identity so we can determine which
+                    # individual object is being updated for each item in the
+                    # incoming data
+                    objects = self.object
+                    identities = [self.get_identity(self.to_native(obj)) for obj in objects]
+                    identity_to_objects = dict(zip(identities, objects))
+
+                if hasattr(data, '__iter__') and not isinstance(data, (dict, six.text_type)):
+                    for item in data:
+                        if update:
+                            # Determine which object we're updating
+                            identity = self.get_identity(item)
+                            self.object = identity_to_objects.pop(identity, None)
+
+                        ret.append(self.from_native(item, None))
+                        errors.append(self._errors)
+
+                    if update:
+                        self._deleted = identity_to_objects.values()
+
+                    self._errors = any(errors) and errors or []
+                else:
+                    self._errors = {'non_field_errors': ['Expected a list of items']}
             else:
                 ret = self.from_native(data, files)
 
@@ -394,6 +440,9 @@ class BaseSerializer(Field):
     def save_object(self, obj, **kwargs):
         obj.save(**kwargs)
 
+    def delete_object(self, obj):
+        obj.delete()
+
     def save(self, **kwargs):
         """
         Save the deserialized object and return it.
@@ -402,6 +451,10 @@ class BaseSerializer(Field):
             [self.save_object(item, **kwargs) for item in self.object]
         else:
             self.save_object(self.object, **kwargs)
+
+        if self.allow_delete and self._deleted:
+            [self.delete_object(item) for item in self._deleted]
+
         return self.object
 
 
@@ -690,3 +743,13 @@ class HyperlinkedModelSerializer(ModelSerializer):
             'many': to_many
         }
         return HyperlinkedRelatedField(**kwargs)
+
+    def get_identity(self, data):
+        """
+        This hook is required for bulk update.
+        We need to override the default, to use the url as the identity.
+        """
+        try:
+            return data.get('url', None)
+        except AttributeError:
+            return None

rest_framework/tests/serializer.py

@@ -261,34 +261,6 @@ class ValidationTests(TestCase):
         self.assertEqual(serializer.is_valid(), True)
         self.assertEqual(serializer.errors, {})
 
-    def test_bad_type_data_is_false(self):
-        """
-        Data of the wrong type is not valid.
-        """
-        data = ['i am', 'a', 'list']
-        serializer = CommentSerializer(self.comment, data=data, many=True)
-        self.assertEqual(serializer.is_valid(), False)
-        self.assertTrue(isinstance(serializer.errors, list))
-
-        self.assertEqual(
-            serializer.errors,
-            [
-                {'non_field_errors': ['Invalid data']},
-                {'non_field_errors': ['Invalid data']},
-                {'non_field_errors': ['Invalid data']}
-            ]
-        )
-
-        data = 'and i am a string'
-        serializer = CommentSerializer(self.comment, data=data)
-        self.assertEqual(serializer.is_valid(), False)
-        self.assertEqual(serializer.errors, {'non_field_errors': ['Invalid data']})
-
-        data = 42
-        serializer = CommentSerializer(self.comment, data=data)
-        self.assertEqual(serializer.is_valid(), False)
-        self.assertEqual(serializer.errors, {'non_field_errors': ['Invalid data']})
-
     def test_cross_field_validation(self):
 
         class CommentSerializerWithCrossFieldValidator(CommentSerializer):

rest_framework/tests/serializer_bulk_update.py

+"""
+Tests to cover bulk create and update using serializers.
+"""
+from __future__ import unicode_literals
+from django.test import TestCase
+from rest_framework import serializers
+
+
+class BulkCreateSerializerTests(TestCase):
+    """
+    Creating multiple instances using serializers.
+    """
+
+    def setUp(self):
+        class BookSerializer(serializers.Serializer):
+            id = serializers.IntegerField()
+            title = serializers.CharField(max_length=100)
+            author = serializers.CharField(max_length=100)
+
+        self.BookSerializer = BookSerializer
+
+    def test_bulk_create_success(self):
+        """
+        Correct bulk update serialization should return the input data.
+        """
+
+        data = [
+            {
+                'id': 0,
+                'title': 'The electric kool-aid acid test',
+                'author': 'Tom Wolfe'
+            }, {
+                'id': 1,
+                'title': 'If this is a man',
+                'author': 'Primo Levi'
+            }, {
+                'id': 2,
+                'title': 'The wind-up bird chronicle',
+                'author': 'Haruki Murakami'
+            }
+        ]
+
+        serializer = self.BookSerializer(data=data, many=True)
+        self.assertEqual(serializer.is_valid(), True)
+        self.assertEqual(serializer.object, data)
+
+    def test_bulk_create_errors(self):
+        """
+        Correct bulk update serialization should return the input data.
+        """
+
+        data = [
+            {
+                'id': 0,
+                'title': 'The electric kool-aid acid test',
+                'author': 'Tom Wolfe'
+            }, {
+                'id': 1,
+                'title': 'If this is a man',
+                'author': 'Primo Levi'
+            }, {
+                'id': 'foo',
+                'title': 'The wind-up bird chronicle',
+                'author': 'Haruki Murakami'
+            }
+        ]
+        expected_errors = [
+            {},
+            {},
+            {'id': ['Enter a whole number.']}
+        ]
+
+        serializer = self.BookSerializer(data=data, many=True)
+        self.assertEqual(serializer.is_valid(), False)
+        self.assertEqual(serializer.errors, expected_errors)
+
+    def test_invalid_list_datatype(self):
+        """
+        Data containing list of incorrect data type should return errors.
+        """
+        data = ['foo', 'bar', 'baz']
+        serializer = self.BookSerializer(data=data, many=True)
+        self.assertEqual(serializer.is_valid(), False)
+
+        expected_errors = [
+                {'non_field_errors': ['Invalid data']},
+                {'non_field_errors': ['Invalid data']},
+                {'non_field_errors': ['Invalid data']}
+        ]
+
+        self.assertEqual(serializer.errors, expected_errors)
+
+    def test_invalid_single_datatype(self):
+        """
+        Data containing a single incorrect data type should return errors.
+        """
+        data = 123
+        serializer = self.BookSerializer(data=data, many=True)
+        self.assertEqual(serializer.is_valid(), False)
+
+        expected_errors = {'non_field_errors': ['Expected a list of items']}
+
+        self.assertEqual(serializer.errors, expected_errors)
+
+    def test_invalid_single_object(self):
+        """
+        Data containing only a single object, instead of a list of objects
+        should return errors.
+        """
+        data = {
+            'id': 0,
+            'title': 'The electric kool-aid acid test',
+            'author': 'Tom Wolfe'
+        }
+        serializer = self.BookSerializer(data=data, many=True)
+        self.assertEqual(serializer.is_valid(), False)
+
+        expected_errors = {'non_field_errors': ['Expected a list of items']}
+
+        self.assertEqual(serializer.errors, expected_errors)
+
+
+class BulkUpdateSerializerTests(TestCase):
+    """
+    Updating multiple instances using serializers.
+    """
+
+    def setUp(self):
+        class Book(object):
+            """
+            A data type that can be persisted to a mock storage backend
+            with `.save()` and `.delete()`.
+            """
+            object_map = {}
+
+            def __init__(self, id, title, author):
+                self.id = id
+                self.title = title
+                self.author = author
+
+            def save(self):
+                Book.object_map[self.id] = self
+
+            def delete(self):
+                del Book.object_map[self.id]
+
+        class BookSerializer(serializers.Serializer):
+            id = serializers.IntegerField()
+            title = serializers.CharField(max_length=100)
+            author = serializers.CharField(max_length=100)
+
+            def restore_object(self, attrs, instance=None):
+                if instance:
+                    instance.id = attrs['id']
+                    instance.title = attrs['title']
+                    instance.author = attrs['author']
+                    return instance
+                return Book(**attrs)
+
+        self.Book = Book
+        self.BookSerializer = BookSerializer
+
+        data = [
+            {
+                'id': 0,
+                'title': 'The electric kool-aid acid test',
+                'author': 'Tom Wolfe'
+            }, {
+                'id': 1,
+                'title': 'If this is a man',
+                'author': 'Primo Levi'
+            }, {
+                'id': 2,
+                'title': 'The wind-up bird chronicle',
+                'author': 'Haruki Murakami'
+            }
+        ]
+
+        for item in data:
+            book = Book(item['id'], item['title'], item['author'])
+            book.save()
+
+    def books(self):
+        """
+        Return all the objects in the mock storage backend.
+        """
+        return self.Book.object_map.values()
+
+    def test_bulk_update_success(self):
+        """
+        Correct bulk update serialization should return the input data.
+        """
+        data = [
+            {
+                'id': 0,
+                'title': 'The electric kool-aid acid test',
+                'author': 'Tom Wolfe'
+            }, {
+                'id': 2,
+                'title': 'Kafka on the shore',
+                'author': 'Haruki Murakami'
+            }
+        ]
+        serializer = self.BookSerializer(self.books(), data=data, many=True, allow_delete=True)
+        self.assertEqual(serializer.is_valid(), True)
+        self.assertEqual(serializer.data, data)
+        serializer.save()
+        new_data = self.BookSerializer(self.books(), many=True).data
+        self.assertEqual(data, new_data)
+
+    def test_bulk_update_and_create(self):
+        """
+        Bulk update serialization may also include created items.
+        """
+        data = [
+            {
+                'id': 0,
+                'title': 'The electric kool-aid acid test',
+                'author': 'Tom Wolfe'
+            }, {
+                'id': 3,
+                'title': 'Kafka on the shore',
+                'author': 'Haruki Murakami'
+            }
+        ]
+        serializer = self.BookSerializer(self.books(), data=data, many=True, allow_delete=True)
+        self.assertEqual(serializer.is_valid(), True)
+        self.assertEqual(serializer.data, data)
+        serializer.save()
+        new_data = self.BookSerializer(self.books(), many=True).data
+        self.assertEqual(data, new_data)
+
+    def test_bulk_update_error(self):
+        """
+        Incorrect bulk update serialization should return error data.
+        """
+        data = [
+            {
+                'id': 0,
+                'title': 'The electric kool-aid acid test',
+                'author': 'Tom Wolfe'
+            }, {
+                'id': 'foo',
+                'title': 'Kafka on the shore',
+                'author': 'Haruki Murakami'
+            }
+        ]
+        expected_errors = [
+            {},
+            {'id': ['Enter a whole number.']}
+        ]
+        serializer = self.BookSerializer(self.books(), data=data, many=True, allow_delete=True)
+        self.assertEqual(serializer.is_valid(), False)
+        self.assertEqual(serializer.errors, expected_errors)