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Diffstat (limited to 'docs/api-guide/serializers.md')
| -rw-r--r-- | docs/api-guide/serializers.md | 44 |
1 files changed, 27 insertions, 17 deletions
diff --git a/docs/api-guide/serializers.md b/docs/api-guide/serializers.md index a3694510..2d0ff79a 100644 --- a/docs/api-guide/serializers.md +++ b/docs/api-guide/serializers.md @@ -1,4 +1,4 @@ -<a class="github" href="serializers.py"></a> +source: serializers.py # Serializers @@ -21,7 +21,7 @@ Let's start by creating a simple object we can use for example purposes: self.email = email self.content = content self.created = created or datetime.datetime.now() - + comment = Comment(email='leila@example.com', content='foo bar') We'll declare a serializer that we can use to serialize and deserialize `Comment` objects. @@ -45,7 +45,7 @@ Declaring a serializer looks very similar to declaring a form: instance.content = attrs.get('content', instance.content) instance.created = attrs.get('created', instance.created) return instance - return Comment(**attrs) + return Comment(**attrs) The first part of serializer class defines the fields that get serialized/deserialized. The `restore_object` method defines how fully fledged instances get created when deserializing data. @@ -83,8 +83,8 @@ If you need to customize the serialized value of a particular field, you can do These methods are essentially the reverse of `validate_<fieldname>` (see *Validation* below.) ## Deserializing objects - -Deserialization is similar. First we parse a stream into Python native datatypes... + +Deserialization is similar. First we parse a stream into Python native datatypes... from StringIO import StringIO from rest_framework.parsers import JSONParser @@ -174,7 +174,7 @@ To save the deserialized objects created by a serializer, call the `.save()` met The default behavior of the method is to simply call `.save()` on the deserialized object instance. You can override the default save behaviour by overriding the `.save_object(obj)` method on the serializer class. -The generic views provided by REST framework call the `.save()` method when updating or creating entities. +The generic views provided by REST framework call the `.save()` method when updating or creating entities. ## Dealing with nested objects @@ -288,12 +288,12 @@ By default the serializer class will use the `id` key on the incoming data to de slug = serializers.CharField(max_length=100) created = serializers.DateTimeField() ... # Various other fields - + def get_identity(self, data): """ This hook is required for bulk update. We need to override the default, to use the slug as the identity. - + Note that the data has not yet been validated at this point, so we need to deal gracefully with incorrect datatypes. """ @@ -361,7 +361,7 @@ The `depth` option should be set to an integer value that indicates the depth of If you want to customize the way the serialization is done (e.g. using `allow_add_remove`) you'll need to define the field yourself. -## Specifying which fields should be read-only +## Specifying which fields should be read-only You may wish to specify multiple fields as read-only. Instead of adding each field explicitly with the `read_only=True` attribute, you may use the `read_only_fields` Meta option, like so: @@ -371,9 +371,9 @@ You may wish to specify multiple fields as read-only. Instead of adding each fi fields = ('id', 'account_name', 'users', 'created') read_only_fields = ('account_name',) -Model fields which have `editable=False` set, and `AutoField` fields will be set to read-only by default, and do not need to be added to the `read_only_fields` option. +Model fields which have `editable=False` set, and `AutoField` fields will be set to read-only by default, and do not need to be added to the `read_only_fields` option. -## Specifying which fields should be write-only +## Specifying which fields should be write-only You may wish to specify multiple fields as write-only. Instead of adding each field explicitly with the `write_only=True` attribute, you may use the `write_only_fields` Meta option, like so: @@ -387,12 +387,12 @@ You may wish to specify multiple fields as write-only. Instead of adding each f """ Instantiate a new User instance. """ - assert instance is None, 'Cannot update users with CreateUserSerializer' + assert instance is None, 'Cannot update users with CreateUserSerializer' user = User(email=attrs['email'], username=attrs['username']) user.set_password(attrs['password']) return user - -## Specifying fields explicitly + +## Specifying fields explicitly You can add extra fields to a `ModelSerializer` or override the default fields by declaring fields on the class, just as you would for a `Serializer` class. @@ -413,6 +413,16 @@ Alternative representations include serializing using hyperlinks, serializing co For full details see the [serializer relations][relations] documentation. +## Inheritance of the 'Meta' class + +The inner `Meta` class on serializers is not inherited from parent classes by default. This is the same behaviour as with Django's `Model` and `ModelForm` classes. If you want the `Meta` class to inherit from a parent class you must do so explicitly. For example: + + class AccountSerializer(MyBaseSerializer): + class Meta(MyBaseSerializer.Meta): + model = Account + +Typically we would recommend *not* using inheritance on inner Meta classes, but instead declaring all options explicitly. + --- # HyperlinkedModelSerializer @@ -514,10 +524,10 @@ For example, if you wanted to be able to set which fields should be used by a se def __init__(self, *args, **kwargs): # Don't pass the 'fields' arg up to the superclass fields = kwargs.pop('fields', None) - + # Instantiate the superclass normally super(DynamicFieldsModelSerializer, self).__init__(*args, **kwargs) - + if fields: # Drop any fields that are not specified in the `fields` argument. allowed = set(fields) @@ -540,7 +550,7 @@ This would then allow you to do the following: ## Customising the default fields -The `field_mapping` attribute is a dictionary that maps model classes to serializer classes. Overriding the attribute will let you set a different set of default serializer classes. +The `field_mapping` attribute is a dictionary that maps model classes to serializer classes. Overriding the attribute will let you set a different set of default serializer classes. For more advanced customization than simply changing the default serializer class you can override various `get_<field_type>_field` methods. Doing so will allow you to customize the arguments that each serializer field is initialized with. Each of these methods may either return a field or serializer instance, or `None`. |